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diff --git a/doc/src/sgml/html/functions-info.html b/doc/src/sgml/html/functions-info.html new file mode 100644 index 0000000..21ba058 --- /dev/null +++ b/doc/src/sgml/html/functions-info.html @@ -0,0 +1,1774 @@ +<?xml version="1.0" encoding="UTF-8" standalone="no"?> +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>9.26. System Information Functions and Operators</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="functions-srf.html" title="9.25. Set Returning Functions" /><link rel="next" href="functions-admin.html" title="9.27. System Administration Functions" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">9.26. System Information Functions and Operators</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="functions-srf.html" title="9.25. Set Returning Functions">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="functions.html" title="Chapter 9. Functions and Operators">Up</a></td><th width="60%" align="center">Chapter 9. Functions and Operators</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 15.4 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="functions-admin.html" title="9.27. System Administration Functions">Next</a></td></tr></table><hr /></div><div class="sect1" id="FUNCTIONS-INFO"><div class="titlepage"><div><div><h2 class="title" style="clear: both">9.26. System Information Functions and Operators</h2></div></div></div><p> + <a class="xref" href="functions-info.html#FUNCTIONS-INFO-SESSION-TABLE" title="Table 9.66. Session Information Functions">Table 9.66</a> shows several + functions that extract session and system information. + </p><p> + In addition to the functions listed in this section, there are a number of + functions related to the statistics system that also provide system + information. See <a class="xref" href="monitoring-stats.html#MONITORING-STATS-VIEWS" title="28.2.2. Viewing Statistics">Section 28.2.2</a> for more + information. + </p><div class="table" id="FUNCTIONS-INFO-SESSION-TABLE"><p class="title"><strong>Table 9.66. Session Information Functions</strong></p><div class="table-contents"><table class="table" summary="Session Information Functions" border="1"><colgroup><col /></colgroup><thead><tr><th class="func_table_entry"><p class="func_signature"> + Function + </p> + <p> + Description + </p></th></tr></thead><tbody><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.4.2.2.1.1.1.1" class="indexterm"></a> + <code class="function">current_catalog</code> + → <code class="returnvalue">name</code> + </p> + <p class="func_signature"> + <a id="id-1.5.8.32.4.2.2.1.1.2.1" class="indexterm"></a> + <code class="function">current_database</code> () + → <code class="returnvalue">name</code> + </p> + <p> + Returns the name of the current database. (Databases are + called <span class="quote">“<span class="quote">catalogs</span>”</span> in the SQL standard, + so <code class="function">current_catalog</code> is the standard's + spelling.) + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.4.2.2.2.1.1.1" class="indexterm"></a> + <code class="function">current_query</code> () + → <code class="returnvalue">text</code> + </p> + <p> + Returns the text of the currently executing query, as submitted + by the client (which might contain more than one statement). + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.4.2.2.3.1.1.1" class="indexterm"></a> + <code class="function">current_role</code> + → <code class="returnvalue">name</code> + </p> + <p> + This is equivalent to <code class="function">current_user</code>. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.4.2.2.4.1.1.1" class="indexterm"></a> + <a id="id-1.5.8.32.4.2.2.4.1.1.2" class="indexterm"></a> + <code class="function">current_schema</code> + → <code class="returnvalue">name</code> + </p> + <p class="func_signature"> + <code class="function">current_schema</code> () + → <code class="returnvalue">name</code> + </p> + <p> + Returns the name of the schema that is first in the search path (or a + null value if the search path is empty). This is the schema that will + be used for any tables or other named objects that are created without + specifying a target schema. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.4.2.2.5.1.1.1" class="indexterm"></a> + <a id="id-1.5.8.32.4.2.2.5.1.1.2" class="indexterm"></a> + <code class="function">current_schemas</code> ( <em class="parameter"><code>include_implicit</code></em> <code class="type">boolean</code> ) + → <code class="returnvalue">name[]</code> + </p> + <p> + Returns an array of the names of all schemas presently in the + effective search path, in their priority order. (Items in the current + <a class="xref" href="runtime-config-client.html#GUC-SEARCH-PATH">search_path</a> setting that do not correspond to + existing, searchable schemas are omitted.) If the Boolean argument + is <code class="literal">true</code>, then implicitly-searched system schemas + such as <code class="literal">pg_catalog</code> are included in the result. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.4.2.2.6.1.1.1" class="indexterm"></a> + <a id="id-1.5.8.32.4.2.2.6.1.1.2" class="indexterm"></a> + <code class="function">current_user</code> + → <code class="returnvalue">name</code> + </p> + <p> + Returns the user name of the current execution context. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.4.2.2.7.1.1.1" class="indexterm"></a> + <code class="function">inet_client_addr</code> () + → <code class="returnvalue">inet</code> + </p> + <p> + Returns the IP address of the current client, + or <code class="literal">NULL</code> if the current connection is via a + Unix-domain socket. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.4.2.2.8.1.1.1" class="indexterm"></a> + <code class="function">inet_client_port</code> () + → <code class="returnvalue">integer</code> + </p> + <p> + Returns the IP port number of the current client, + or <code class="literal">NULL</code> if the current connection is via a + Unix-domain socket. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.4.2.2.9.1.1.1" class="indexterm"></a> + <code class="function">inet_server_addr</code> () + → <code class="returnvalue">inet</code> + </p> + <p> + Returns the IP address on which the server accepted the current + connection, + or <code class="literal">NULL</code> if the current connection is via a + Unix-domain socket. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.4.2.2.10.1.1.1" class="indexterm"></a> + <code class="function">inet_server_port</code> () + → <code class="returnvalue">integer</code> + </p> + <p> + Returns the IP port number on which the server accepted the current + connection, + or <code class="literal">NULL</code> if the current connection is via a + Unix-domain socket. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.4.2.2.11.1.1.1" class="indexterm"></a> + <code class="function">pg_backend_pid</code> () + → <code class="returnvalue">integer</code> + </p> + <p> + Returns the process ID of the server process attached to the current + session. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.4.2.2.12.1.1.1" class="indexterm"></a> + <code class="function">pg_blocking_pids</code> ( <code class="type">integer</code> ) + → <code class="returnvalue">integer[]</code> + </p> + <p> + Returns an array of the process ID(s) of the sessions that are + blocking the server process with the specified process ID from + acquiring a lock, or an empty array if there is no such server process + or it is not blocked. + </p> + <p> + One server process blocks another if it either holds a lock that + conflicts with the blocked process's lock request (hard block), or is + waiting for a lock that would conflict with the blocked process's lock + request and is ahead of it in the wait queue (soft block). When using + parallel queries the result always lists client-visible process IDs + (that is, <code class="function">pg_backend_pid</code> results) even if the + actual lock is held or awaited by a child worker process. As a result + of that, there may be duplicated PIDs in the result. Also note that + when a prepared transaction holds a conflicting lock, it will be + represented by a zero process ID. + </p> + <p> + Frequent calls to this function could have some impact on database + performance, because it needs exclusive access to the lock manager's + shared state for a short time. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.4.2.2.13.1.1.1" class="indexterm"></a> + <code class="function">pg_conf_load_time</code> () + → <code class="returnvalue">timestamp with time zone</code> + </p> + <p> + Returns the time when the server configuration files were last loaded. + If the current session was alive at the time, this will be the time + when the session itself re-read the configuration files (so the + reading will vary a little in different sessions). Otherwise it is + the time when the postmaster process re-read the configuration files. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.4.2.2.14.1.1.1" class="indexterm"></a> + <a id="id-1.5.8.32.4.2.2.14.1.1.2" class="indexterm"></a> + <a id="id-1.5.8.32.4.2.2.14.1.1.3" class="indexterm"></a> + <a id="id-1.5.8.32.4.2.2.14.1.1.4" class="indexterm"></a> + <code class="function">pg_current_logfile</code> ( [<span class="optional"> <code class="type">text</code> </span>] ) + → <code class="returnvalue">text</code> + </p> + <p> + Returns the path name of the log file currently in use by the logging + collector. The path includes the <a class="xref" href="runtime-config-logging.html#GUC-LOG-DIRECTORY">log_directory</a> + directory and the individual log file name. The result + is <code class="literal">NULL</code> if the logging collector is disabled. + When multiple log files exist, each in a different + format, <code class="function">pg_current_logfile</code> without an argument + returns the path of the file having the first format found in the + ordered list: <code class="literal">stderr</code>, + <code class="literal">csvlog</code>, <code class="literal">jsonlog</code>. + <code class="literal">NULL</code> is returned if no log file has any of these + formats. + To request information about a specific log file format, supply + either <code class="literal">csvlog</code>, <code class="literal">jsonlog</code> or + <code class="literal">stderr</code> as the + value of the optional parameter. The result is <code class="literal">NULL</code> + if the log format requested is not configured in + <a class="xref" href="runtime-config-logging.html#GUC-LOG-DESTINATION">log_destination</a>. + The result reflects the contents of + the <code class="filename">current_logfiles</code> file. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.4.2.2.15.1.1.1" class="indexterm"></a> + <code class="function">pg_my_temp_schema</code> () + → <code class="returnvalue">oid</code> + </p> + <p> + Returns the OID of the current session's temporary schema, or zero if + it has none (because it has not created any temporary tables). + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.4.2.2.16.1.1.1" class="indexterm"></a> + <code class="function">pg_is_other_temp_schema</code> ( <code class="type">oid</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Returns true if the given OID is the OID of another session's + temporary schema. (This can be useful, for example, to exclude other + sessions' temporary tables from a catalog display.) + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.4.2.2.17.1.1.1" class="indexterm"></a> + <code class="function">pg_jit_available</code> () + → <code class="returnvalue">boolean</code> + </p> + <p> + Returns true if a <acronym class="acronym">JIT</acronym> compiler extension is + available (see <a class="xref" href="jit.html" title="Chapter 32. Just-in-Time Compilation (JIT)">Chapter 32</a>) and the + <a class="xref" href="runtime-config-query.html#GUC-JIT">jit</a> configuration parameter is set to + <code class="literal">on</code>. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.4.2.2.18.1.1.1" class="indexterm"></a> + <code class="function">pg_listening_channels</code> () + → <code class="returnvalue">setof text</code> + </p> + <p> + Returns the set of names of asynchronous notification channels that + the current session is listening to. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.4.2.2.19.1.1.1" class="indexterm"></a> + <code class="function">pg_notification_queue_usage</code> () + → <code class="returnvalue">double precision</code> + </p> + <p> + Returns the fraction (0–1) of the asynchronous notification + queue's maximum size that is currently occupied by notifications that + are waiting to be processed. + See <a class="xref" href="sql-listen.html" title="LISTEN"><span class="refentrytitle">LISTEN</span></a> and <a class="xref" href="sql-notify.html" title="NOTIFY"><span class="refentrytitle">NOTIFY</span></a> + for more information. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.4.2.2.20.1.1.1" class="indexterm"></a> + <code class="function">pg_postmaster_start_time</code> () + → <code class="returnvalue">timestamp with time zone</code> + </p> + <p> + Returns the time when the server started. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.4.2.2.21.1.1.1" class="indexterm"></a> + <code class="function">pg_safe_snapshot_blocking_pids</code> ( <code class="type">integer</code> ) + → <code class="returnvalue">integer[]</code> + </p> + <p> + Returns an array of the process ID(s) of the sessions that are blocking + the server process with the specified process ID from acquiring a safe + snapshot, or an empty array if there is no such server process or it + is not blocked. + </p> + <p> + A session running a <code class="literal">SERIALIZABLE</code> transaction blocks + a <code class="literal">SERIALIZABLE READ ONLY DEFERRABLE</code> transaction + from acquiring a snapshot until the latter determines that it is safe + to avoid taking any predicate locks. See + <a class="xref" href="transaction-iso.html#XACT-SERIALIZABLE" title="13.2.3. Serializable Isolation Level">Section 13.2.3</a> for more information about + serializable and deferrable transactions. + </p> + <p> + Frequent calls to this function could have some impact on database + performance, because it needs access to the predicate lock manager's + shared state for a short time. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.4.2.2.22.1.1.1" class="indexterm"></a> + <code class="function">pg_trigger_depth</code> () + → <code class="returnvalue">integer</code> + </p> + <p> + Returns the current nesting level + of <span class="productname">PostgreSQL</span> triggers (0 if not called, + directly or indirectly, from inside a trigger). + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.4.2.2.23.1.1.1" class="indexterm"></a> + <code class="function">session_user</code> + → <code class="returnvalue">name</code> + </p> + <p> + Returns the session user's name. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.4.2.2.24.1.1.1" class="indexterm"></a> + <code class="function">user</code> + → <code class="returnvalue">name</code> + </p> + <p> + This is equivalent to <code class="function">current_user</code>. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.4.2.2.25.1.1.1" class="indexterm"></a> + <code class="function">version</code> () + → <code class="returnvalue">text</code> + </p> + <p> + Returns a string describing the <span class="productname">PostgreSQL</span> + server's version. You can also get this information from + <a class="xref" href="runtime-config-preset.html#GUC-SERVER-VERSION">server_version</a>, or for a machine-readable + version use <a class="xref" href="runtime-config-preset.html#GUC-SERVER-VERSION-NUM">server_version_num</a>. Software + developers should use <code class="varname">server_version_num</code> (available + since 8.2) or <a class="xref" href="libpq-status.html#LIBPQ-PQSERVERVERSION"><code class="function">PQserverVersion</code></a> instead of + parsing the text version. + </p></td></tr></tbody></table></div></div><br class="table-break" /><div class="note"><h3 class="title">Note</h3><p> + <code class="function">current_catalog</code>, + <code class="function">current_role</code>, + <code class="function">current_schema</code>, + <code class="function">current_user</code>, + <code class="function">session_user</code>, + and <code class="function">user</code> have special syntactic status + in <acronym class="acronym">SQL</acronym>: they must be called without trailing + parentheses. In PostgreSQL, parentheses can optionally be used with + <code class="function">current_schema</code>, but not with the others. + </p></div><p> + The <code class="function">session_user</code> is normally the user who initiated + the current database connection; but superusers can change this setting + with <a class="xref" href="sql-set-session-authorization.html" title="SET SESSION AUTHORIZATION"><span class="refentrytitle">SET SESSION AUTHORIZATION</span></a>. + The <code class="function">current_user</code> is the user identifier + that is applicable for permission checking. Normally it is equal + to the session user, but it can be changed with + <a class="xref" href="sql-set-role.html" title="SET ROLE"><span class="refentrytitle">SET ROLE</span></a>. + It also changes during the execution of + functions with the attribute <code class="literal">SECURITY DEFINER</code>. + In Unix parlance, the session user is the <span class="quote">“<span class="quote">real user</span>”</span> and + the current user is the <span class="quote">“<span class="quote">effective user</span>”</span>. + <code class="function">current_role</code> and <code class="function">user</code> are + synonyms for <code class="function">current_user</code>. (The SQL standard draws + a distinction between <code class="function">current_role</code> + and <code class="function">current_user</code>, but <span class="productname">PostgreSQL</span> + does not, since it unifies users and roles into a single kind of entity.) + </p><a id="id-1.5.8.32.7" class="indexterm"></a><p> + <a class="xref" href="functions-info.html#FUNCTIONS-INFO-ACCESS-TABLE" title="Table 9.67. Access Privilege Inquiry Functions">Table 9.67</a> lists functions that + allow querying object access privileges programmatically. + (See <a class="xref" href="ddl-priv.html" title="5.7. Privileges">Section 5.7</a> for more information about + privileges.) + In these functions, the user whose privileges are being inquired about + can be specified by name or by OID + (<code class="structname">pg_authid</code>.<code class="structfield">oid</code>), or if + the name is given as <code class="literal">public</code> then the privileges of the + PUBLIC pseudo-role are checked. Also, the <em class="parameter"><code>user</code></em> + argument can be omitted entirely, in which case + the <code class="function">current_user</code> is assumed. + The object that is being inquired about can be specified either by name or + by OID, too. When specifying by name, a schema name can be included if + relevant. + The access privilege of interest is specified by a text string, which must + evaluate to one of the appropriate privilege keywords for the object's type + (e.g., <code class="literal">SELECT</code>). Optionally, <code class="literal">WITH GRANT + OPTION</code> can be added to a privilege type to test whether the + privilege is held with grant option. Also, multiple privilege types can be + listed separated by commas, in which case the result will be true if any of + the listed privileges is held. (Case of the privilege string is not + significant, and extra whitespace is allowed between but not within + privilege names.) + Some examples: +</p><pre class="programlisting"> +SELECT has_table_privilege('myschema.mytable', 'select'); +SELECT has_table_privilege('joe', 'mytable', 'INSERT, SELECT WITH GRANT OPTION'); +</pre><p> + </p><div class="table" id="FUNCTIONS-INFO-ACCESS-TABLE"><p class="title"><strong>Table 9.67. Access Privilege Inquiry Functions</strong></p><div class="table-contents"><table class="table" summary="Access Privilege Inquiry Functions" border="1"><colgroup><col /></colgroup><thead><tr><th class="func_table_entry"><p class="func_signature"> + Function + </p> + <p> + Description + </p></th></tr></thead><tbody><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.9.2.2.1.1.1.1" class="indexterm"></a> + <code class="function">has_any_column_privilege</code> ( + [<span class="optional"> <em class="parameter"><code>user</code></em> <code class="type">name</code> or <code class="type">oid</code>, </span>] + <em class="parameter"><code>table</code></em> <code class="type">text</code> or <code class="type">oid</code>, + <em class="parameter"><code>privilege</code></em> <code class="type">text</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Does user have privilege for any column of table? + This succeeds either if the privilege is held for the whole table, or + if there is a column-level grant of the privilege for at least one + column. + Allowable privilege types are + <code class="literal">SELECT</code>, <code class="literal">INSERT</code>, + <code class="literal">UPDATE</code>, and <code class="literal">REFERENCES</code>. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.9.2.2.2.1.1.1" class="indexterm"></a> + <code class="function">has_column_privilege</code> ( + [<span class="optional"> <em class="parameter"><code>user</code></em> <code class="type">name</code> or <code class="type">oid</code>, </span>] + <em class="parameter"><code>table</code></em> <code class="type">text</code> or <code class="type">oid</code>, + <em class="parameter"><code>column</code></em> <code class="type">text</code> or <code class="type">smallint</code>, + <em class="parameter"><code>privilege</code></em> <code class="type">text</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Does user have privilege for the specified table column? + This succeeds either if the privilege is held for the whole table, or + if there is a column-level grant of the privilege for the column. + The column can be specified by name or by attribute number + (<code class="structname">pg_attribute</code>.<code class="structfield">attnum</code>). + Allowable privilege types are + <code class="literal">SELECT</code>, <code class="literal">INSERT</code>, + <code class="literal">UPDATE</code>, and <code class="literal">REFERENCES</code>. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.9.2.2.3.1.1.1" class="indexterm"></a> + <code class="function">has_database_privilege</code> ( + [<span class="optional"> <em class="parameter"><code>user</code></em> <code class="type">name</code> or <code class="type">oid</code>, </span>] + <em class="parameter"><code>database</code></em> <code class="type">text</code> or <code class="type">oid</code>, + <em class="parameter"><code>privilege</code></em> <code class="type">text</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Does user have privilege for database? + Allowable privilege types are + <code class="literal">CREATE</code>, + <code class="literal">CONNECT</code>, + <code class="literal">TEMPORARY</code>, and + <code class="literal">TEMP</code> (which is equivalent to + <code class="literal">TEMPORARY</code>). + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.9.2.2.4.1.1.1" class="indexterm"></a> + <code class="function">has_foreign_data_wrapper_privilege</code> ( + [<span class="optional"> <em class="parameter"><code>user</code></em> <code class="type">name</code> or <code class="type">oid</code>, </span>] + <em class="parameter"><code>fdw</code></em> <code class="type">text</code> or <code class="type">oid</code>, + <em class="parameter"><code>privilege</code></em> <code class="type">text</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Does user have privilege for foreign-data wrapper? + The only allowable privilege type is <code class="literal">USAGE</code>. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.9.2.2.5.1.1.1" class="indexterm"></a> + <code class="function">has_function_privilege</code> ( + [<span class="optional"> <em class="parameter"><code>user</code></em> <code class="type">name</code> or <code class="type">oid</code>, </span>] + <em class="parameter"><code>function</code></em> <code class="type">text</code> or <code class="type">oid</code>, + <em class="parameter"><code>privilege</code></em> <code class="type">text</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Does user have privilege for function? + The only allowable privilege type is <code class="literal">EXECUTE</code>. + </p> + <p> + When specifying a function by name rather than by OID, the allowed + input is the same as for the <code class="type">regprocedure</code> data type (see + <a class="xref" href="datatype-oid.html" title="8.19. Object Identifier Types">Section 8.19</a>). + An example is: +</p><pre class="programlisting"> +SELECT has_function_privilege('joeuser', 'myfunc(int, text)', 'execute'); +</pre><p> + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.9.2.2.6.1.1.1" class="indexterm"></a> + <code class="function">has_language_privilege</code> ( + [<span class="optional"> <em class="parameter"><code>user</code></em> <code class="type">name</code> or <code class="type">oid</code>, </span>] + <em class="parameter"><code>language</code></em> <code class="type">text</code> or <code class="type">oid</code>, + <em class="parameter"><code>privilege</code></em> <code class="type">text</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Does user have privilege for language? + The only allowable privilege type is <code class="literal">USAGE</code>. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.9.2.2.7.1.1.1" class="indexterm"></a> + <code class="function">has_parameter_privilege</code> ( + [<span class="optional"> <em class="parameter"><code>user</code></em> <code class="type">name</code> or <code class="type">oid</code>, </span>] + <em class="parameter"><code>parameter</code></em> <code class="type">text</code>, + <em class="parameter"><code>privilege</code></em> <code class="type">text</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Does user have privilege for configuration parameter? + The parameter name is case-insensitive. + Allowable privilege types are <code class="literal">SET</code> + and <code class="literal">ALTER SYSTEM</code>. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.9.2.2.8.1.1.1" class="indexterm"></a> + <code class="function">has_schema_privilege</code> ( + [<span class="optional"> <em class="parameter"><code>user</code></em> <code class="type">name</code> or <code class="type">oid</code>, </span>] + <em class="parameter"><code>schema</code></em> <code class="type">text</code> or <code class="type">oid</code>, + <em class="parameter"><code>privilege</code></em> <code class="type">text</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Does user have privilege for schema? + Allowable privilege types are + <code class="literal">CREATE</code> and + <code class="literal">USAGE</code>. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.9.2.2.9.1.1.1" class="indexterm"></a> + <code class="function">has_sequence_privilege</code> ( + [<span class="optional"> <em class="parameter"><code>user</code></em> <code class="type">name</code> or <code class="type">oid</code>, </span>] + <em class="parameter"><code>sequence</code></em> <code class="type">text</code> or <code class="type">oid</code>, + <em class="parameter"><code>privilege</code></em> <code class="type">text</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Does user have privilege for sequence? + Allowable privilege types are + <code class="literal">USAGE</code>, + <code class="literal">SELECT</code>, and + <code class="literal">UPDATE</code>. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.9.2.2.10.1.1.1" class="indexterm"></a> + <code class="function">has_server_privilege</code> ( + [<span class="optional"> <em class="parameter"><code>user</code></em> <code class="type">name</code> or <code class="type">oid</code>, </span>] + <em class="parameter"><code>server</code></em> <code class="type">text</code> or <code class="type">oid</code>, + <em class="parameter"><code>privilege</code></em> <code class="type">text</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Does user have privilege for foreign server? + The only allowable privilege type is <code class="literal">USAGE</code>. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.9.2.2.11.1.1.1" class="indexterm"></a> + <code class="function">has_table_privilege</code> ( + [<span class="optional"> <em class="parameter"><code>user</code></em> <code class="type">name</code> or <code class="type">oid</code>, </span>] + <em class="parameter"><code>table</code></em> <code class="type">text</code> or <code class="type">oid</code>, + <em class="parameter"><code>privilege</code></em> <code class="type">text</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Does user have privilege for table? + Allowable privilege types + are <code class="literal">SELECT</code>, <code class="literal">INSERT</code>, + <code class="literal">UPDATE</code>, <code class="literal">DELETE</code>, + <code class="literal">TRUNCATE</code>, <code class="literal">REFERENCES</code>, + and <code class="literal">TRIGGER</code>. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.9.2.2.12.1.1.1" class="indexterm"></a> + <code class="function">has_tablespace_privilege</code> ( + [<span class="optional"> <em class="parameter"><code>user</code></em> <code class="type">name</code> or <code class="type">oid</code>, </span>] + <em class="parameter"><code>tablespace</code></em> <code class="type">text</code> or <code class="type">oid</code>, + <em class="parameter"><code>privilege</code></em> <code class="type">text</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Does user have privilege for tablespace? + The only allowable privilege type is <code class="literal">CREATE</code>. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.9.2.2.13.1.1.1" class="indexterm"></a> + <code class="function">has_type_privilege</code> ( + [<span class="optional"> <em class="parameter"><code>user</code></em> <code class="type">name</code> or <code class="type">oid</code>, </span>] + <em class="parameter"><code>type</code></em> <code class="type">text</code> or <code class="type">oid</code>, + <em class="parameter"><code>privilege</code></em> <code class="type">text</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Does user have privilege for data type? + The only allowable privilege type is <code class="literal">USAGE</code>. + When specifying a type by name rather than by OID, the allowed input + is the same as for the <code class="type">regtype</code> data type (see + <a class="xref" href="datatype-oid.html" title="8.19. Object Identifier Types">Section 8.19</a>). + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.9.2.2.14.1.1.1" class="indexterm"></a> + <code class="function">pg_has_role</code> ( + [<span class="optional"> <em class="parameter"><code>user</code></em> <code class="type">name</code> or <code class="type">oid</code>, </span>] + <em class="parameter"><code>role</code></em> <code class="type">text</code> or <code class="type">oid</code>, + <em class="parameter"><code>privilege</code></em> <code class="type">text</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Does user have privilege for role? + Allowable privilege types are + <code class="literal">MEMBER</code> and <code class="literal">USAGE</code>. + <code class="literal">MEMBER</code> denotes direct or indirect membership in + the role (that is, the right to do <code class="command">SET ROLE</code>), while + <code class="literal">USAGE</code> denotes whether the privileges of the role + are immediately available without doing <code class="command">SET ROLE</code>. + This function does not allow the special case of + setting <em class="parameter"><code>user</code></em> to <code class="literal">public</code>, + because the PUBLIC pseudo-role can never be a member of real roles. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.9.2.2.15.1.1.1" class="indexterm"></a> + <code class="function">row_security_active</code> ( + <em class="parameter"><code>table</code></em> <code class="type">text</code> or <code class="type">oid</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Is row-level security active for the specified table in the context of + the current user and current environment? + </p></td></tr></tbody></table></div></div><br class="table-break" /><p> + <a class="xref" href="functions-info.html#FUNCTIONS-ACLITEM-OP-TABLE" title="Table 9.68. aclitem Operators">Table 9.68</a> shows the operators + available for the <code class="type">aclitem</code> type, which is the catalog + representation of access privileges. See <a class="xref" href="ddl-priv.html" title="5.7. Privileges">Section 5.7</a> + for information about how to read access privilege values. + </p><div class="table" id="FUNCTIONS-ACLITEM-OP-TABLE"><p class="title"><strong>Table 9.68. <code class="type">aclitem</code> Operators</strong></p><div class="table-contents"><table class="table" summary="aclitem Operators" border="1"><colgroup><col /></colgroup><thead><tr><th class="func_table_entry"><p class="func_signature"> + Operator + </p> + <p> + Description + </p> + <p> + Example(s) + </p></th></tr></thead><tbody><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.11.2.2.1.1.1.1" class="indexterm"></a> + <code class="type">aclitem</code> <code class="literal">=</code> <code class="type">aclitem</code> + → <code class="returnvalue">boolean</code> + </p> + <p> + Are <code class="type">aclitem</code>s equal? (Notice that + type <code class="type">aclitem</code> lacks the usual set of comparison + operators; it has only equality. In turn, <code class="type">aclitem</code> + arrays can only be compared for equality.) + </p> + <p> + <code class="literal">'calvin=r*w/hobbes'::aclitem = 'calvin=r*w*/hobbes'::aclitem</code> + → <code class="returnvalue">f</code> + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.11.2.2.2.1.1.1" class="indexterm"></a> + <code class="type">aclitem[]</code> <code class="literal">@></code> <code class="type">aclitem</code> + → <code class="returnvalue">boolean</code> + </p> + <p> + Does array contain the specified privileges? (This is true if there + is an array entry that matches the <code class="type">aclitem</code>'s grantee and + grantor, and has at least the specified set of privileges.) + </p> + <p> + <code class="literal">'{calvin=r*w/hobbes,hobbes=r*w*/postgres}'::aclitem[] @> 'calvin=r*/hobbes'::aclitem</code> + → <code class="returnvalue">t</code> + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <code class="type">aclitem[]</code> <code class="literal">~</code> <code class="type">aclitem</code> + → <code class="returnvalue">boolean</code> + </p> + <p> + This is a deprecated alias for <code class="literal">@></code>. + </p> + <p> + <code class="literal">'{calvin=r*w/hobbes,hobbes=r*w*/postgres}'::aclitem[] ~ 'calvin=r*/hobbes'::aclitem</code> + → <code class="returnvalue">t</code> + </p></td></tr></tbody></table></div></div><br class="table-break" /><p> + <a class="xref" href="functions-info.html#FUNCTIONS-ACLITEM-FN-TABLE" title="Table 9.69. aclitem Functions">Table 9.69</a> shows some additional + functions to manage the <code class="type">aclitem</code> type. + </p><div class="table" id="FUNCTIONS-ACLITEM-FN-TABLE"><p class="title"><strong>Table 9.69. <code class="type">aclitem</code> Functions</strong></p><div class="table-contents"><table class="table" summary="aclitem Functions" border="1"><colgroup><col /></colgroup><thead><tr><th class="func_table_entry"><p class="func_signature"> + Function + </p> + <p> + Description + </p></th></tr></thead><tbody><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.13.2.2.1.1.1.1" class="indexterm"></a> + <code class="function">acldefault</code> ( + <em class="parameter"><code>type</code></em> <code class="type">"char"</code>, + <em class="parameter"><code>ownerId</code></em> <code class="type">oid</code> ) + → <code class="returnvalue">aclitem[]</code> + </p> + <p> + Constructs an <code class="type">aclitem</code> array holding the default access + privileges for an object of type <em class="parameter"><code>type</code></em> belonging + to the role with OID <em class="parameter"><code>ownerId</code></em>. This represents + the access privileges that will be assumed when an object's ACL entry + is null. (The default access privileges are described in + <a class="xref" href="ddl-priv.html" title="5.7. Privileges">Section 5.7</a>.) + The <em class="parameter"><code>type</code></em> parameter must be one of + 'c' for <code class="literal">COLUMN</code>, + 'r' for <code class="literal">TABLE</code> and table-like objects, + 's' for <code class="literal">SEQUENCE</code>, + 'd' for <code class="literal">DATABASE</code>, + 'f' for <code class="literal">FUNCTION</code> or <code class="literal">PROCEDURE</code>, + 'l' for <code class="literal">LANGUAGE</code>, + 'L' for <code class="literal">LARGE OBJECT</code>, + 'n' for <code class="literal">SCHEMA</code>, + 'p' for <code class="literal">PARAMETER</code>, + 't' for <code class="literal">TABLESPACE</code>, + 'F' for <code class="literal">FOREIGN DATA WRAPPER</code>, + 'S' for <code class="literal">FOREIGN SERVER</code>, + or + 'T' for <code class="literal">TYPE</code> or <code class="literal">DOMAIN</code>. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.13.2.2.2.1.1.1" class="indexterm"></a> + <code class="function">aclexplode</code> ( <code class="type">aclitem[]</code> ) + → <code class="returnvalue">setof record</code> + ( <em class="parameter"><code>grantor</code></em> <code class="type">oid</code>, + <em class="parameter"><code>grantee</code></em> <code class="type">oid</code>, + <em class="parameter"><code>privilege_type</code></em> <code class="type">text</code>, + <em class="parameter"><code>is_grantable</code></em> <code class="type">boolean</code> ) + </p> + <p> + Returns the <code class="type">aclitem</code> array as a set of rows. + If the grantee is the pseudo-role PUBLIC, it is represented by zero in + the <em class="parameter"><code>grantee</code></em> column. Each granted privilege is + represented as <code class="literal">SELECT</code>, <code class="literal">INSERT</code>, + etc. Note that each privilege is broken out as a separate row, so + only one keyword appears in the <em class="parameter"><code>privilege_type</code></em> + column. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.13.2.2.3.1.1.1" class="indexterm"></a> + <code class="function">makeaclitem</code> ( + <em class="parameter"><code>grantee</code></em> <code class="type">oid</code>, + <em class="parameter"><code>grantor</code></em> <code class="type">oid</code>, + <em class="parameter"><code>privileges</code></em> <code class="type">text</code>, + <em class="parameter"><code>is_grantable</code></em> <code class="type">boolean</code> ) + → <code class="returnvalue">aclitem</code> + </p> + <p> + Constructs an <code class="type">aclitem</code> with the given properties. + </p></td></tr></tbody></table></div></div><br class="table-break" /><p> + <a class="xref" href="functions-info.html#FUNCTIONS-INFO-SCHEMA-TABLE" title="Table 9.70. Schema Visibility Inquiry Functions">Table 9.70</a> shows functions that + determine whether a certain object is <em class="firstterm">visible</em> in the + current schema search path. + For example, a table is said to be visible if its + containing schema is in the search path and no table of the same + name appears earlier in the search path. This is equivalent to the + statement that the table can be referenced by name without explicit + schema qualification. Thus, to list the names of all visible tables: +</p><pre class="programlisting"> +SELECT relname FROM pg_class WHERE pg_table_is_visible(oid); +</pre><p> + For functions and operators, an object in the search path is said to be + visible if there is no object of the same name <span class="emphasis"><em>and argument data + type(s)</em></span> earlier in the path. For operator classes and families, + both the name and the associated index access method are considered. + </p><a id="id-1.5.8.32.15" class="indexterm"></a><div class="table" id="FUNCTIONS-INFO-SCHEMA-TABLE"><p class="title"><strong>Table 9.70. Schema Visibility Inquiry Functions</strong></p><div class="table-contents"><table class="table" summary="Schema Visibility Inquiry Functions" border="1"><colgroup><col /></colgroup><thead><tr><th class="func_table_entry"><p class="func_signature"> + Function + </p> + <p> + Description + </p></th></tr></thead><tbody><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.16.2.2.1.1.1.1" class="indexterm"></a> + <code class="function">pg_collation_is_visible</code> ( <em class="parameter"><code>collation</code></em> <code class="type">oid</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Is collation visible in search path? + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.16.2.2.2.1.1.1" class="indexterm"></a> + <code class="function">pg_conversion_is_visible</code> ( <em class="parameter"><code>conversion</code></em> <code class="type">oid</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Is conversion visible in search path? + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.16.2.2.3.1.1.1" class="indexterm"></a> + <code class="function">pg_function_is_visible</code> ( <em class="parameter"><code>function</code></em> <code class="type">oid</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Is function visible in search path? + (This also works for procedures and aggregates.) + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.16.2.2.4.1.1.1" class="indexterm"></a> + <code class="function">pg_opclass_is_visible</code> ( <em class="parameter"><code>opclass</code></em> <code class="type">oid</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Is operator class visible in search path? + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.16.2.2.5.1.1.1" class="indexterm"></a> + <code class="function">pg_operator_is_visible</code> ( <em class="parameter"><code>operator</code></em> <code class="type">oid</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Is operator visible in search path? + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.16.2.2.6.1.1.1" class="indexterm"></a> + <code class="function">pg_opfamily_is_visible</code> ( <em class="parameter"><code>opclass</code></em> <code class="type">oid</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Is operator family visible in search path? + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.16.2.2.7.1.1.1" class="indexterm"></a> + <code class="function">pg_statistics_obj_is_visible</code> ( <em class="parameter"><code>stat</code></em> <code class="type">oid</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Is statistics object visible in search path? + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.16.2.2.8.1.1.1" class="indexterm"></a> + <code class="function">pg_table_is_visible</code> ( <em class="parameter"><code>table</code></em> <code class="type">oid</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Is table visible in search path? + (This works for all types of relations, including views, materialized + views, indexes, sequences and foreign tables.) + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.16.2.2.9.1.1.1" class="indexterm"></a> + <code class="function">pg_ts_config_is_visible</code> ( <em class="parameter"><code>config</code></em> <code class="type">oid</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Is text search configuration visible in search path? + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.16.2.2.10.1.1.1" class="indexterm"></a> + <code class="function">pg_ts_dict_is_visible</code> ( <em class="parameter"><code>dict</code></em> <code class="type">oid</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Is text search dictionary visible in search path? + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.16.2.2.11.1.1.1" class="indexterm"></a> + <code class="function">pg_ts_parser_is_visible</code> ( <em class="parameter"><code>parser</code></em> <code class="type">oid</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Is text search parser visible in search path? + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.16.2.2.12.1.1.1" class="indexterm"></a> + <code class="function">pg_ts_template_is_visible</code> ( <em class="parameter"><code>template</code></em> <code class="type">oid</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Is text search template visible in search path? + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.16.2.2.13.1.1.1" class="indexterm"></a> + <code class="function">pg_type_is_visible</code> ( <em class="parameter"><code>type</code></em> <code class="type">oid</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Is type (or domain) visible in search path? + </p></td></tr></tbody></table></div></div><br class="table-break" /><p> + All these functions require object OIDs to identify the object to be + checked. If you want to test an object by name, it is convenient to use + the OID alias types (<code class="type">regclass</code>, <code class="type">regtype</code>, + <code class="type">regprocedure</code>, <code class="type">regoperator</code>, <code class="type">regconfig</code>, + or <code class="type">regdictionary</code>), + for example: +</p><pre class="programlisting"> +SELECT pg_type_is_visible('myschema.widget'::regtype); +</pre><p> + Note that it would not make much sense to test a non-schema-qualified + type name in this way — if the name can be recognized at all, it must be visible. + </p><p> + <a class="xref" href="functions-info.html#FUNCTIONS-INFO-CATALOG-TABLE" title="Table 9.71. System Catalog Information Functions">Table 9.71</a> lists functions that + extract information from the system catalogs. + </p><div class="table" id="FUNCTIONS-INFO-CATALOG-TABLE"><p class="title"><strong>Table 9.71. System Catalog Information Functions</strong></p><div class="table-contents"><table class="table" summary="System Catalog Information Functions" border="1"><colgroup><col /></colgroup><thead><tr><th class="func_table_entry"><p class="func_signature"> + Function + </p> + <p> + Description + </p></th></tr></thead><tbody><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.1.1.1.1" class="indexterm"></a> + <code class="function">format_type</code> ( <em class="parameter"><code>type</code></em> <code class="type">oid</code>, <em class="parameter"><code>typemod</code></em> <code class="type">integer</code> ) + → <code class="returnvalue">text</code> + </p> + <p> + Returns the SQL name for a data type that is identified by its type + OID and possibly a type modifier. Pass NULL for the type modifier if + no specific modifier is known. + </p></td></tr><tr><td id="PG-CHAR-TO-ENCODING" class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.2.1.1.1" class="indexterm"></a> + <code class="function">pg_char_to_encoding</code> ( <em class="parameter"><code>encoding</code></em> <code class="type">name</code> ) + → <code class="returnvalue">integer</code> + </p> + <p> + Converts the supplied encoding name into an integer representing the + internal identifier used in some system catalog tables. + Returns <code class="literal">-1</code> if an unknown encoding name is provided. + </p></td></tr><tr><td id="PG-ENCODING-TO-CHAR" class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.3.1.1.1" class="indexterm"></a> + <code class="function">pg_encoding_to_char</code> ( <em class="parameter"><code>encoding</code></em> <code class="type">integer</code> ) + → <code class="returnvalue">name</code> + </p> + <p> + Converts the integer used as the internal identifier of an encoding in some + system catalog tables into a human-readable string. + Returns an empty string if an invalid encoding number is provided. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.4.1.1.1" class="indexterm"></a> + <code class="function">pg_get_catalog_foreign_keys</code> () + → <code class="returnvalue">setof record</code> + ( <em class="parameter"><code>fktable</code></em> <code class="type">regclass</code>, + <em class="parameter"><code>fkcols</code></em> <code class="type">text[]</code>, + <em class="parameter"><code>pktable</code></em> <code class="type">regclass</code>, + <em class="parameter"><code>pkcols</code></em> <code class="type">text[]</code>, + <em class="parameter"><code>is_array</code></em> <code class="type">boolean</code>, + <em class="parameter"><code>is_opt</code></em> <code class="type">boolean</code> ) + </p> + <p> + Returns a set of records describing the foreign key relationships + that exist within the <span class="productname">PostgreSQL</span> system + catalogs. + The <em class="parameter"><code>fktable</code></em> column contains the name of the + referencing catalog, and the <em class="parameter"><code>fkcols</code></em> column + contains the name(s) of the referencing column(s). Similarly, + the <em class="parameter"><code>pktable</code></em> column contains the name of the + referenced catalog, and the <em class="parameter"><code>pkcols</code></em> column + contains the name(s) of the referenced column(s). + If <em class="parameter"><code>is_array</code></em> is true, the last referencing + column is an array, each of whose elements should match some entry + in the referenced catalog. + If <em class="parameter"><code>is_opt</code></em> is true, the referencing column(s) + are allowed to contain zeroes instead of a valid reference. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.5.1.1.1" class="indexterm"></a> + <code class="function">pg_get_constraintdef</code> ( <em class="parameter"><code>constraint</code></em> <code class="type">oid</code> [<span class="optional">, <em class="parameter"><code>pretty</code></em> <code class="type">boolean</code> </span>] ) + → <code class="returnvalue">text</code> + </p> + <p> + Reconstructs the creating command for a constraint. + (This is a decompiled reconstruction, not the original text + of the command.) + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.6.1.1.1" class="indexterm"></a> + <code class="function">pg_get_expr</code> ( <em class="parameter"><code>expr</code></em> <code class="type">pg_node_tree</code>, <em class="parameter"><code>relation</code></em> <code class="type">oid</code> [<span class="optional">, <em class="parameter"><code>pretty</code></em> <code class="type">boolean</code> </span>] ) + → <code class="returnvalue">text</code> + </p> + <p> + Decompiles the internal form of an expression stored in the system + catalogs, such as the default value for a column. If the expression + might contain Vars, specify the OID of the relation they refer to as + the second parameter; if no Vars are expected, passing zero is + sufficient. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.7.1.1.1" class="indexterm"></a> + <code class="function">pg_get_functiondef</code> ( <em class="parameter"><code>func</code></em> <code class="type">oid</code> ) + → <code class="returnvalue">text</code> + </p> + <p> + Reconstructs the creating command for a function or procedure. + (This is a decompiled reconstruction, not the original text + of the command.) + The result is a complete <code class="command">CREATE OR REPLACE FUNCTION</code> + or <code class="command">CREATE OR REPLACE PROCEDURE</code> statement. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.8.1.1.1" class="indexterm"></a> + <code class="function">pg_get_function_arguments</code> ( <em class="parameter"><code>func</code></em> <code class="type">oid</code> ) + → <code class="returnvalue">text</code> + </p> + <p> + Reconstructs the argument list of a function or procedure, in the form + it would need to appear in within <code class="command">CREATE FUNCTION</code> + (including default values). + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.9.1.1.1" class="indexterm"></a> + <code class="function">pg_get_function_identity_arguments</code> ( <em class="parameter"><code>func</code></em> <code class="type">oid</code> ) + → <code class="returnvalue">text</code> + </p> + <p> + Reconstructs the argument list necessary to identify a function or + procedure, in the form it would need to appear in within commands such + as <code class="command">ALTER FUNCTION</code>. This form omits default values. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.10.1.1.1" class="indexterm"></a> + <code class="function">pg_get_function_result</code> ( <em class="parameter"><code>func</code></em> <code class="type">oid</code> ) + → <code class="returnvalue">text</code> + </p> + <p> + Reconstructs the <code class="literal">RETURNS</code> clause of a function, in + the form it would need to appear in within <code class="command">CREATE + FUNCTION</code>. Returns <code class="literal">NULL</code> for a procedure. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.11.1.1.1" class="indexterm"></a> + <code class="function">pg_get_indexdef</code> ( <em class="parameter"><code>index</code></em> <code class="type">oid</code> [<span class="optional">, <em class="parameter"><code>column</code></em> <code class="type">integer</code>, <em class="parameter"><code>pretty</code></em> <code class="type">boolean</code> </span>] ) + → <code class="returnvalue">text</code> + </p> + <p> + Reconstructs the creating command for an index. + (This is a decompiled reconstruction, not the original text + of the command.) If <em class="parameter"><code>column</code></em> is supplied and is + not zero, only the definition of that column is reconstructed. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.12.1.1.1" class="indexterm"></a> + <code class="function">pg_get_keywords</code> () + → <code class="returnvalue">setof record</code> + ( <em class="parameter"><code>word</code></em> <code class="type">text</code>, + <em class="parameter"><code>catcode</code></em> <code class="type">"char"</code>, + <em class="parameter"><code>barelabel</code></em> <code class="type">boolean</code>, + <em class="parameter"><code>catdesc</code></em> <code class="type">text</code>, + <em class="parameter"><code>baredesc</code></em> <code class="type">text</code> ) + </p> + <p> + Returns a set of records describing the SQL keywords recognized by the + server. The <em class="parameter"><code>word</code></em> column contains the + keyword. The <em class="parameter"><code>catcode</code></em> column contains a + category code: <code class="literal">U</code> for an unreserved + keyword, <code class="literal">C</code> for a keyword that can be a column + name, <code class="literal">T</code> for a keyword that can be a type or + function name, or <code class="literal">R</code> for a fully reserved keyword. + The <em class="parameter"><code>barelabel</code></em> column + contains <code class="literal">true</code> if the keyword can be used as + a <span class="quote">“<span class="quote">bare</span>”</span> column label in <code class="command">SELECT</code> lists, + or <code class="literal">false</code> if it can only be used + after <code class="literal">AS</code>. + The <em class="parameter"><code>catdesc</code></em> column contains a + possibly-localized string describing the keyword's category. + The <em class="parameter"><code>baredesc</code></em> column contains a + possibly-localized string describing the keyword's column label status. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.13.1.1.1" class="indexterm"></a> + <code class="function">pg_get_ruledef</code> ( <em class="parameter"><code>rule</code></em> <code class="type">oid</code> [<span class="optional">, <em class="parameter"><code>pretty</code></em> <code class="type">boolean</code> </span>] ) + → <code class="returnvalue">text</code> + </p> + <p> + Reconstructs the creating command for a rule. + (This is a decompiled reconstruction, not the original text + of the command.) + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.14.1.1.1" class="indexterm"></a> + <code class="function">pg_get_serial_sequence</code> ( <em class="parameter"><code>table</code></em> <code class="type">text</code>, <em class="parameter"><code>column</code></em> <code class="type">text</code> ) + → <code class="returnvalue">text</code> + </p> + <p> + Returns the name of the sequence associated with a column, + or NULL if no sequence is associated with the column. + If the column is an identity column, the associated sequence is the + sequence internally created for that column. + For columns created using one of the serial types + (<code class="type">serial</code>, <code class="type">smallserial</code>, <code class="type">bigserial</code>), + it is the sequence created for that serial column definition. + In the latter case, the association can be modified or removed + with <code class="command">ALTER SEQUENCE OWNED BY</code>. + (This function probably should have been + called <code class="function">pg_get_owned_sequence</code>; its current name + reflects the fact that it has historically been used with serial-type + columns.) The first parameter is a table name with optional + schema, and the second parameter is a column name. Because the first + parameter potentially contains both schema and table names, it is + parsed per usual SQL rules, meaning it is lower-cased by default. + The second parameter, being just a column name, is treated literally + and so has its case preserved. The result is suitably formatted + for passing to the sequence functions (see + <a class="xref" href="functions-sequence.html" title="9.17. Sequence Manipulation Functions">Section 9.17</a>). + </p> + <p> + A typical use is in reading the current value of the sequence for an + identity or serial column, for example: +</p><pre class="programlisting"> +SELECT currval(pg_get_serial_sequence('sometable', 'id')); +</pre><p> + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.15.1.1.1" class="indexterm"></a> + <code class="function">pg_get_statisticsobjdef</code> ( <em class="parameter"><code>statobj</code></em> <code class="type">oid</code> ) + → <code class="returnvalue">text</code> + </p> + <p> + Reconstructs the creating command for an extended statistics object. + (This is a decompiled reconstruction, not the original text + of the command.) + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.16.1.1.1" class="indexterm"></a> +<code class="function">pg_get_triggerdef</code> ( <em class="parameter"><code>trigger</code></em> <code class="type">oid</code> [<span class="optional">, <em class="parameter"><code>pretty</code></em> <code class="type">boolean</code> </span>] ) + → <code class="returnvalue">text</code> + </p> + <p> + Reconstructs the creating command for a trigger. + (This is a decompiled reconstruction, not the original text + of the command.) + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.17.1.1.1" class="indexterm"></a> + <code class="function">pg_get_userbyid</code> ( <em class="parameter"><code>role</code></em> <code class="type">oid</code> ) + → <code class="returnvalue">name</code> + </p> + <p> + Returns a role's name given its OID. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.18.1.1.1" class="indexterm"></a> + <code class="function">pg_get_viewdef</code> ( <em class="parameter"><code>view</code></em> <code class="type">oid</code> [<span class="optional">, <em class="parameter"><code>pretty</code></em> <code class="type">boolean</code> </span>] ) + → <code class="returnvalue">text</code> + </p> + <p> + Reconstructs the underlying <code class="command">SELECT</code> command for a + view or materialized view. (This is a decompiled reconstruction, not + the original text of the command.) + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <code class="function">pg_get_viewdef</code> ( <em class="parameter"><code>view</code></em> <code class="type">oid</code>, <em class="parameter"><code>wrap_column</code></em> <code class="type">integer</code> ) + → <code class="returnvalue">text</code> + </p> + <p> + Reconstructs the underlying <code class="command">SELECT</code> command for a + view or materialized view. (This is a decompiled reconstruction, not + the original text of the command.) In this form of the function, + pretty-printing is always enabled, and long lines are wrapped to try + to keep them shorter than the specified number of columns. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <code class="function">pg_get_viewdef</code> ( <em class="parameter"><code>view</code></em> <code class="type">text</code> [<span class="optional">, <em class="parameter"><code>pretty</code></em> <code class="type">boolean</code> </span>] ) + → <code class="returnvalue">text</code> + </p> + <p> + Reconstructs the underlying <code class="command">SELECT</code> command for a + view or materialized view, working from a textual name for the view + rather than its OID. (This is deprecated; use the OID variant + instead.) + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.21.1.1.1" class="indexterm"></a> + <code class="function">pg_index_column_has_property</code> ( <em class="parameter"><code>index</code></em> <code class="type">regclass</code>, <em class="parameter"><code>column</code></em> <code class="type">integer</code>, <em class="parameter"><code>property</code></em> <code class="type">text</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Tests whether an index column has the named property. + Common index column properties are listed in + <a class="xref" href="functions-info.html#FUNCTIONS-INFO-INDEX-COLUMN-PROPS" title="Table 9.72. Index Column Properties">Table 9.72</a>. + (Note that extension access methods can define additional property + names for their indexes.) + <code class="literal">NULL</code> is returned if the property name is not known + or does not apply to the particular object, or if the OID or column + number does not identify a valid object. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.22.1.1.1" class="indexterm"></a> + <code class="function">pg_index_has_property</code> ( <em class="parameter"><code>index</code></em> <code class="type">regclass</code>, <em class="parameter"><code>property</code></em> <code class="type">text</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Tests whether an index has the named property. + Common index properties are listed in + <a class="xref" href="functions-info.html#FUNCTIONS-INFO-INDEX-PROPS" title="Table 9.73. Index Properties">Table 9.73</a>. + (Note that extension access methods can define additional property + names for their indexes.) + <code class="literal">NULL</code> is returned if the property name is not known + or does not apply to the particular object, or if the OID does not + identify a valid object. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.23.1.1.1" class="indexterm"></a> + <code class="function">pg_indexam_has_property</code> ( <em class="parameter"><code>am</code></em> <code class="type">oid</code>, <em class="parameter"><code>property</code></em> <code class="type">text</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Tests whether an index access method has the named property. + Access method properties are listed in + <a class="xref" href="functions-info.html#FUNCTIONS-INFO-INDEXAM-PROPS" title="Table 9.74. Index Access Method Properties">Table 9.74</a>. + <code class="literal">NULL</code> is returned if the property name is not known + or does not apply to the particular object, or if the OID does not + identify a valid object. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.24.1.1.1" class="indexterm"></a> + <code class="function">pg_options_to_table</code> ( <em class="parameter"><code>options_array</code></em> <code class="type">text[]</code> ) + → <code class="returnvalue">setof record</code> + ( <em class="parameter"><code>option_name</code></em> <code class="type">text</code>, + <em class="parameter"><code>option_value</code></em> <code class="type">text</code> ) + </p> + <p> + Returns the set of storage options represented by a value from + <code class="structname">pg_class</code>.<code class="structfield">reloptions</code> or + <code class="structname">pg_attribute</code>.<code class="structfield">attoptions</code>. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.25.1.1.1" class="indexterm"></a> + <code class="function">pg_settings_get_flags</code> ( <em class="parameter"><code>guc</code></em> <code class="type">text</code> ) + → <code class="returnvalue">text[]</code> + </p> + <p> + Returns an array of the flags associated with the given GUC, or + <code class="literal">NULL</code> if it does not exist. The result is + an empty array if the GUC exists but there are no flags to show. + Only the most useful flags listed in + <a class="xref" href="functions-info.html#FUNCTIONS-PG-SETTINGS-FLAGS" title="Table 9.75. GUC Flags">Table 9.75</a> are exposed. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.26.1.1.1" class="indexterm"></a> + <code class="function">pg_tablespace_databases</code> ( <em class="parameter"><code>tablespace</code></em> <code class="type">oid</code> ) + → <code class="returnvalue">setof oid</code> + </p> + <p> + Returns the set of OIDs of databases that have objects stored in the + specified tablespace. If this function returns any rows, the + tablespace is not empty and cannot be dropped. To identify the specific + objects populating the tablespace, you will need to connect to the + database(s) identified by <code class="function">pg_tablespace_databases</code> + and query their <code class="structname">pg_class</code> catalogs. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.27.1.1.1" class="indexterm"></a> + <code class="function">pg_tablespace_location</code> ( <em class="parameter"><code>tablespace</code></em> <code class="type">oid</code> ) + → <code class="returnvalue">text</code> + </p> + <p> + Returns the file system path that this tablespace is located in. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.28.1.1.1" class="indexterm"></a> + <code class="function">pg_typeof</code> ( <code class="type">"any"</code> ) + → <code class="returnvalue">regtype</code> + </p> + <p> + Returns the OID of the data type of the value that is passed to it. + This can be helpful for troubleshooting or dynamically constructing + SQL queries. The function is declared as + returning <code class="type">regtype</code>, which is an OID alias type (see + <a class="xref" href="datatype-oid.html" title="8.19. Object Identifier Types">Section 8.19</a>); this means that it is the same as an + OID for comparison purposes but displays as a type name. + </p> + <p> + For example: +</p><pre class="programlisting"> +SELECT pg_typeof(33); + pg_typeof +----------- + integer + +SELECT typlen FROM pg_type WHERE oid = pg_typeof(33); + typlen +-------- + 4 +</pre><p> + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.29.1.1.1" class="indexterm"></a> + <code class="function">COLLATION FOR</code> ( <code class="type">"any"</code> ) + → <code class="returnvalue">text</code> + </p> + <p> + Returns the name of the collation of the value that is passed to it. + The value is quoted and schema-qualified if necessary. If no + collation was derived for the argument expression, + then <code class="literal">NULL</code> is returned. If the argument is not of a + collatable data type, then an error is raised. + </p> + <p> + For example: +</p><pre class="programlisting"> +SELECT collation for (description) FROM pg_description LIMIT 1; + pg_collation_for +------------------ + "default" + +SELECT collation for ('foo' COLLATE "de_DE"); + pg_collation_for +------------------ + "de_DE" +</pre><p> + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.30.1.1.1" class="indexterm"></a> + <code class="function">to_regclass</code> ( <code class="type">text</code> ) + → <code class="returnvalue">regclass</code> + </p> + <p> + Translates a textual relation name to its OID. A similar result is + obtained by casting the string to type <code class="type">regclass</code> (see + <a class="xref" href="datatype-oid.html" title="8.19. Object Identifier Types">Section 8.19</a>); however, this function will return + <code class="literal">NULL</code> rather than throwing an error if the name is + not found. Also unlike the cast, this does not accept + a numeric OID as input. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.31.1.1.1" class="indexterm"></a> + <code class="function">to_regcollation</code> ( <code class="type">text</code> ) + → <code class="returnvalue">regcollation</code> + </p> + <p> + Translates a textual collation name to its OID. A similar result is + obtained by casting the string to type <code class="type">regcollation</code> (see + <a class="xref" href="datatype-oid.html" title="8.19. Object Identifier Types">Section 8.19</a>); however, this function will return + <code class="literal">NULL</code> rather than throwing an error if the name is + not found. Also unlike the cast, this does not accept + a numeric OID as input. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.32.1.1.1" class="indexterm"></a> + <code class="function">to_regnamespace</code> ( <code class="type">text</code> ) + → <code class="returnvalue">regnamespace</code> + </p> + <p> + Translates a textual schema name to its OID. A similar result is + obtained by casting the string to type <code class="type">regnamespace</code> (see + <a class="xref" href="datatype-oid.html" title="8.19. Object Identifier Types">Section 8.19</a>); however, this function will return + <code class="literal">NULL</code> rather than throwing an error if the name is + not found. Also unlike the cast, this does not accept + a numeric OID as input. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.33.1.1.1" class="indexterm"></a> + <code class="function">to_regoper</code> ( <code class="type">text</code> ) + → <code class="returnvalue">regoper</code> + </p> + <p> + Translates a textual operator name to its OID. A similar result is + obtained by casting the string to type <code class="type">regoper</code> (see + <a class="xref" href="datatype-oid.html" title="8.19. Object Identifier Types">Section 8.19</a>); however, this function will return + <code class="literal">NULL</code> rather than throwing an error if the name is + not found or is ambiguous. Also unlike the cast, this does not accept + a numeric OID as input. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.34.1.1.1" class="indexterm"></a> + <code class="function">to_regoperator</code> ( <code class="type">text</code> ) + → <code class="returnvalue">regoperator</code> + </p> + <p> + Translates a textual operator name (with parameter types) to its OID. A similar result is + obtained by casting the string to type <code class="type">regoperator</code> (see + <a class="xref" href="datatype-oid.html" title="8.19. Object Identifier Types">Section 8.19</a>); however, this function will return + <code class="literal">NULL</code> rather than throwing an error if the name is + not found. Also unlike the cast, this does not accept + a numeric OID as input. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.35.1.1.1" class="indexterm"></a> + <code class="function">to_regproc</code> ( <code class="type">text</code> ) + → <code class="returnvalue">regproc</code> + </p> + <p> + Translates a textual function or procedure name to its OID. A similar result is + obtained by casting the string to type <code class="type">regproc</code> (see + <a class="xref" href="datatype-oid.html" title="8.19. Object Identifier Types">Section 8.19</a>); however, this function will return + <code class="literal">NULL</code> rather than throwing an error if the name is + not found or is ambiguous. Also unlike the cast, this does not accept + a numeric OID as input. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.36.1.1.1" class="indexterm"></a> + <code class="function">to_regprocedure</code> ( <code class="type">text</code> ) + → <code class="returnvalue">regprocedure</code> + </p> + <p> + Translates a textual function or procedure name (with argument types) to its OID. A similar result is + obtained by casting the string to type <code class="type">regprocedure</code> (see + <a class="xref" href="datatype-oid.html" title="8.19. Object Identifier Types">Section 8.19</a>); however, this function will return + <code class="literal">NULL</code> rather than throwing an error if the name is + not found. Also unlike the cast, this does not accept + a numeric OID as input. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.37.1.1.1" class="indexterm"></a> + <code class="function">to_regrole</code> ( <code class="type">text</code> ) + → <code class="returnvalue">regrole</code> + </p> + <p> + Translates a textual role name to its OID. A similar result is + obtained by casting the string to type <code class="type">regrole</code> (see + <a class="xref" href="datatype-oid.html" title="8.19. Object Identifier Types">Section 8.19</a>); however, this function will return + <code class="literal">NULL</code> rather than throwing an error if the name is + not found. Also unlike the cast, this does not accept + a numeric OID as input. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.19.2.2.38.1.1.1" class="indexterm"></a> + <code class="function">to_regtype</code> ( <code class="type">text</code> ) + → <code class="returnvalue">regtype</code> + </p> + <p> + Translates a textual type name to its OID. A similar result is + obtained by casting the string to type <code class="type">regtype</code> (see + <a class="xref" href="datatype-oid.html" title="8.19. Object Identifier Types">Section 8.19</a>); however, this function will return + <code class="literal">NULL</code> rather than throwing an error if the name is + not found. Also unlike the cast, this does not accept + a numeric OID as input. + </p></td></tr></tbody></table></div></div><br class="table-break" /><p> + Most of the functions that reconstruct (decompile) database objects + have an optional <em class="parameter"><code>pretty</code></em> flag, which + if <code class="literal">true</code> causes the result to + be <span class="quote">“<span class="quote">pretty-printed</span>”</span>. Pretty-printing suppresses unnecessary + parentheses and adds whitespace for legibility. + The pretty-printed format is more readable, but the default format + is more likely to be interpreted the same way by future versions of + <span class="productname">PostgreSQL</span>; so avoid using pretty-printed output + for dump purposes. Passing <code class="literal">false</code> for + the <em class="parameter"><code>pretty</code></em> parameter yields the same result as + omitting the parameter. + </p><div class="table" id="FUNCTIONS-INFO-INDEX-COLUMN-PROPS"><p class="title"><strong>Table 9.72. Index Column Properties</strong></p><div class="table-contents"><table class="table" summary="Index Column Properties" border="1"><colgroup><col /><col /></colgroup><thead><tr><th>Name</th><th>Description</th></tr></thead><tbody><tr><td><code class="literal">asc</code></td><td>Does the column sort in ascending order on a forward scan? + </td></tr><tr><td><code class="literal">desc</code></td><td>Does the column sort in descending order on a forward scan? + </td></tr><tr><td><code class="literal">nulls_first</code></td><td>Does the column sort with nulls first on a forward scan? + </td></tr><tr><td><code class="literal">nulls_last</code></td><td>Does the column sort with nulls last on a forward scan? + </td></tr><tr><td><code class="literal">orderable</code></td><td>Does the column possess any defined sort ordering? + </td></tr><tr><td><code class="literal">distance_orderable</code></td><td>Can the column be scanned in order by a <span class="quote">“<span class="quote">distance</span>”</span> + operator, for example <code class="literal">ORDER BY col <-> constant</code> ? + </td></tr><tr><td><code class="literal">returnable</code></td><td>Can the column value be returned by an index-only scan? + </td></tr><tr><td><code class="literal">search_array</code></td><td>Does the column natively support <code class="literal">col = ANY(array)</code> + searches? + </td></tr><tr><td><code class="literal">search_nulls</code></td><td>Does the column support <code class="literal">IS NULL</code> and + <code class="literal">IS NOT NULL</code> searches? + </td></tr></tbody></table></div></div><br class="table-break" /><div class="table" id="FUNCTIONS-INFO-INDEX-PROPS"><p class="title"><strong>Table 9.73. Index Properties</strong></p><div class="table-contents"><table class="table" summary="Index Properties" border="1"><colgroup><col /><col /></colgroup><thead><tr><th>Name</th><th>Description</th></tr></thead><tbody><tr><td><code class="literal">clusterable</code></td><td>Can the index be used in a <code class="literal">CLUSTER</code> command? + </td></tr><tr><td><code class="literal">index_scan</code></td><td>Does the index support plain (non-bitmap) scans? + </td></tr><tr><td><code class="literal">bitmap_scan</code></td><td>Does the index support bitmap scans? + </td></tr><tr><td><code class="literal">backward_scan</code></td><td>Can the scan direction be changed in mid-scan (to + support <code class="literal">FETCH BACKWARD</code> on a cursor without + needing materialization)? + </td></tr></tbody></table></div></div><br class="table-break" /><div class="table" id="FUNCTIONS-INFO-INDEXAM-PROPS"><p class="title"><strong>Table 9.74. Index Access Method Properties</strong></p><div class="table-contents"><table class="table" summary="Index Access Method Properties" border="1"><colgroup><col /><col /></colgroup><thead><tr><th>Name</th><th>Description</th></tr></thead><tbody><tr><td><code class="literal">can_order</code></td><td>Does the access method support <code class="literal">ASC</code>, + <code class="literal">DESC</code> and related keywords in + <code class="literal">CREATE INDEX</code>? + </td></tr><tr><td><code class="literal">can_unique</code></td><td>Does the access method support unique indexes? + </td></tr><tr><td><code class="literal">can_multi_col</code></td><td>Does the access method support indexes with multiple columns? + </td></tr><tr><td><code class="literal">can_exclude</code></td><td>Does the access method support exclusion constraints? + </td></tr><tr><td><code class="literal">can_include</code></td><td>Does the access method support the <code class="literal">INCLUDE</code> + clause of <code class="literal">CREATE INDEX</code>? + </td></tr></tbody></table></div></div><br class="table-break" /><div class="table" id="FUNCTIONS-PG-SETTINGS-FLAGS"><p class="title"><strong>Table 9.75. GUC Flags</strong></p><div class="table-contents"><table class="table" summary="GUC Flags" border="1"><colgroup><col /><col /></colgroup><thead><tr><th>Flag</th><th>Description</th></tr></thead><tbody><tr><td><code class="literal">EXPLAIN</code></td><td>Parameters with this flag are included in + <code class="command">EXPLAIN (SETTINGS)</code> commands. + </td></tr><tr><td><code class="literal">NO_SHOW_ALL</code></td><td>Parameters with this flag are excluded from + <code class="command">SHOW ALL</code> commands. + </td></tr><tr><td><code class="literal">NO_RESET_ALL</code></td><td>Parameters with this flag are excluded from + <code class="command">RESET ALL</code> commands. + </td></tr><tr><td><code class="literal">NOT_IN_SAMPLE</code></td><td>Parameters with this flag are not included in + <code class="filename">postgresql.conf</code> by default. + </td></tr><tr><td><code class="literal">RUNTIME_COMPUTED</code></td><td>Parameters with this flag are runtime-computed ones. + </td></tr></tbody></table></div></div><br class="table-break" /><p> + <a class="xref" href="functions-info.html#FUNCTIONS-INFO-OBJECT-TABLE" title="Table 9.76. Object Information and Addressing Functions">Table 9.76</a> lists functions related to + database object identification and addressing. + </p><div class="table" id="FUNCTIONS-INFO-OBJECT-TABLE"><p class="title"><strong>Table 9.76. Object Information and Addressing Functions</strong></p><div class="table-contents"><table class="table" summary="Object Information and Addressing Functions" border="1"><colgroup><col /></colgroup><thead><tr><th class="func_table_entry"><p class="func_signature"> + Function + </p> + <p> + Description + </p></th></tr></thead><tbody><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.26.2.2.1.1.1.1" class="indexterm"></a> + <code class="function">pg_describe_object</code> ( <em class="parameter"><code>classid</code></em> <code class="type">oid</code>, <em class="parameter"><code>objid</code></em> <code class="type">oid</code>, <em class="parameter"><code>objsubid</code></em> <code class="type">integer</code> ) + → <code class="returnvalue">text</code> + </p> + <p> + Returns a textual description of a database object identified by + catalog OID, object OID, and sub-object ID (such as a column number + within a table; the sub-object ID is zero when referring to a whole + object). This description is intended to be human-readable, and might + be translated, depending on server configuration. This is especially + useful to determine the identity of an object referenced in the + <code class="structname">pg_depend</code> catalog. This function returns + <code class="literal">NULL</code> values for undefined objects. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.26.2.2.2.1.1.1" class="indexterm"></a> + <code class="function">pg_identify_object</code> ( <em class="parameter"><code>classid</code></em> <code class="type">oid</code>, <em class="parameter"><code>objid</code></em> <code class="type">oid</code>, <em class="parameter"><code>objsubid</code></em> <code class="type">integer</code> ) + → <code class="returnvalue">record</code> + ( <em class="parameter"><code>type</code></em> <code class="type">text</code>, + <em class="parameter"><code>schema</code></em> <code class="type">text</code>, + <em class="parameter"><code>name</code></em> <code class="type">text</code>, + <em class="parameter"><code>identity</code></em> <code class="type">text</code> ) + </p> + <p> + Returns a row containing enough information to uniquely identify the + database object specified by catalog OID, object OID and sub-object + ID. + This information is intended to be machine-readable, and is never + translated. + <em class="parameter"><code>type</code></em> identifies the type of database object; + <em class="parameter"><code>schema</code></em> is the schema name that the object + belongs in, or <code class="literal">NULL</code> for object types that do not + belong to schemas; + <em class="parameter"><code>name</code></em> is the name of the object, quoted if + necessary, if the name (along with schema name, if pertinent) is + sufficient to uniquely identify the object, + otherwise <code class="literal">NULL</code>; + <em class="parameter"><code>identity</code></em> is the complete object identity, with + the precise format depending on object type, and each name within the + format being schema-qualified and quoted as necessary. Undefined + objects are identified with <code class="literal">NULL</code> values. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.26.2.2.3.1.1.1" class="indexterm"></a> + <code class="function">pg_identify_object_as_address</code> ( <em class="parameter"><code>classid</code></em> <code class="type">oid</code>, <em class="parameter"><code>objid</code></em> <code class="type">oid</code>, <em class="parameter"><code>objsubid</code></em> <code class="type">integer</code> ) + → <code class="returnvalue">record</code> + ( <em class="parameter"><code>type</code></em> <code class="type">text</code>, + <em class="parameter"><code>object_names</code></em> <code class="type">text[]</code>, + <em class="parameter"><code>object_args</code></em> <code class="type">text[]</code> ) + </p> + <p> + Returns a row containing enough information to uniquely identify the + database object specified by catalog OID, object OID and sub-object + ID. + The returned information is independent of the current server, that + is, it could be used to identify an identically named object in + another server. + <em class="parameter"><code>type</code></em> identifies the type of database object; + <em class="parameter"><code>object_names</code></em> and + <em class="parameter"><code>object_args</code></em> + are text arrays that together form a reference to the object. + These three values can be passed + to <code class="function">pg_get_object_address</code> to obtain the internal + address of the object. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.26.2.2.4.1.1.1" class="indexterm"></a> + <code class="function">pg_get_object_address</code> ( <em class="parameter"><code>type</code></em> <code class="type">text</code>, <em class="parameter"><code>object_names</code></em> <code class="type">text[]</code>, <em class="parameter"><code>object_args</code></em> <code class="type">text[]</code> ) + → <code class="returnvalue">record</code> + ( <em class="parameter"><code>classid</code></em> <code class="type">oid</code>, + <em class="parameter"><code>objid</code></em> <code class="type">oid</code>, + <em class="parameter"><code>objsubid</code></em> <code class="type">integer</code> ) + </p> + <p> + Returns a row containing enough information to uniquely identify the + database object specified by a type code and object name and argument + arrays. + The returned values are the ones that would be used in system catalogs + such as <code class="structname">pg_depend</code>; they can be passed to + other system functions such as <code class="function">pg_describe_object</code> + or <code class="function">pg_identify_object</code>. + <em class="parameter"><code>classid</code></em> is the OID of the system catalog + containing the object; + <em class="parameter"><code>objid</code></em> is the OID of the object itself, and + <em class="parameter"><code>objsubid</code></em> is the sub-object ID, or zero if none. + This function is the inverse + of <code class="function">pg_identify_object_as_address</code>. + Undefined objects are identified with <code class="literal">NULL</code> values. + </p></td></tr></tbody></table></div></div><br class="table-break" /><a id="id-1.5.8.32.27" class="indexterm"></a><p> + The functions shown in <a class="xref" href="functions-info.html#FUNCTIONS-INFO-COMMENT-TABLE" title="Table 9.77. Comment Information Functions">Table 9.77</a> + extract comments previously stored with the <a class="xref" href="sql-comment.html" title="COMMENT"><span class="refentrytitle">COMMENT</span></a> + command. A null value is returned if no + comment could be found for the specified parameters. + </p><div class="table" id="FUNCTIONS-INFO-COMMENT-TABLE"><p class="title"><strong>Table 9.77. Comment Information Functions</strong></p><div class="table-contents"><table class="table" summary="Comment Information Functions" border="1"><colgroup><col /></colgroup><thead><tr><th class="func_table_entry"><p class="func_signature"> + Function + </p> + <p> + Description + </p></th></tr></thead><tbody><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.29.2.2.1.1.1.1" class="indexterm"></a> + <code class="function">col_description</code> ( <em class="parameter"><code>table</code></em> <code class="type">oid</code>, <em class="parameter"><code>column</code></em> <code class="type">integer</code> ) + → <code class="returnvalue">text</code> + </p> + <p> + Returns the comment for a table column, which is specified by the OID + of its table and its column number. + (<code class="function">obj_description</code> cannot be used for table + columns, since columns do not have OIDs of their own.) + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.29.2.2.2.1.1.1" class="indexterm"></a> + <code class="function">obj_description</code> ( <em class="parameter"><code>object</code></em> <code class="type">oid</code>, <em class="parameter"><code>catalog</code></em> <code class="type">name</code> ) + → <code class="returnvalue">text</code> + </p> + <p> + Returns the comment for a database object specified by its OID and the + name of the containing system catalog. For + example, <code class="literal">obj_description(123456, 'pg_class')</code> would + retrieve the comment for the table with OID 123456. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <code class="function">obj_description</code> ( <em class="parameter"><code>object</code></em> <code class="type">oid</code> ) + → <code class="returnvalue">text</code> + </p> + <p> + Returns the comment for a database object specified by its OID alone. + This is <span class="emphasis"><em>deprecated</em></span> since there is no guarantee + that OIDs are unique across different system catalogs; therefore, the + wrong comment might be returned. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.29.2.2.4.1.1.1" class="indexterm"></a> + <code class="function">shobj_description</code> ( <em class="parameter"><code>object</code></em> <code class="type">oid</code>, <em class="parameter"><code>catalog</code></em> <code class="type">name</code> ) + → <code class="returnvalue">text</code> + </p> + <p> + Returns the comment for a shared database object specified by its OID + and the name of the containing system catalog. This is just + like <code class="function">obj_description</code> except that it is used for + retrieving comments on shared objects (that is, databases, roles, and + tablespaces). Some system catalogs are global to all databases within + each cluster, and the descriptions for objects in them are stored + globally as well. + </p></td></tr></tbody></table></div></div><br class="table-break" /><p> + The functions shown in <a class="xref" href="functions-info.html#FUNCTIONS-PG-SNAPSHOT" title="Table 9.78. Transaction ID and Snapshot Information Functions">Table 9.78</a> + provide server transaction information in an exportable form. The main + use of these functions is to determine which transactions were committed + between two snapshots. + </p><div class="table" id="FUNCTIONS-PG-SNAPSHOT"><p class="title"><strong>Table 9.78. Transaction ID and Snapshot Information Functions</strong></p><div class="table-contents"><table class="table" summary="Transaction ID and Snapshot Information Functions" border="1"><colgroup><col /></colgroup><thead><tr><th class="func_table_entry"><p class="func_signature"> + Function + </p> + <p> + Description + </p></th></tr></thead><tbody><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.31.2.2.1.1.1.1" class="indexterm"></a> + <code class="function">pg_current_xact_id</code> () + → <code class="returnvalue">xid8</code> + </p> + <p> + Returns the current transaction's ID. It will assign a new one if the + current transaction does not have one already (because it has not + performed any database updates). + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.31.2.2.2.1.1.1" class="indexterm"></a> + <code class="function">pg_current_xact_id_if_assigned</code> () + → <code class="returnvalue">xid8</code> + </p> + <p> + Returns the current transaction's ID, or <code class="literal">NULL</code> if no + ID is assigned yet. (It's best to use this variant if the transaction + might otherwise be read-only, to avoid unnecessary consumption of an + XID.) + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.31.2.2.3.1.1.1" class="indexterm"></a> + <code class="function">pg_xact_status</code> ( <code class="type">xid8</code> ) + → <code class="returnvalue">text</code> + </p> + <p> + Reports the commit status of a recent transaction. + The result is one of <code class="literal">in progress</code>, + <code class="literal">committed</code>, or <code class="literal">aborted</code>, + provided that the transaction is recent enough that the system retains + the commit status of that transaction. + If it is old enough that no references to the transaction survive in + the system and the commit status information has been discarded, the + result is <code class="literal">NULL</code>. + Applications might use this function, for example, to determine + whether their transaction committed or aborted after the application + and database server become disconnected while + a <code class="literal">COMMIT</code> is in progress. + Note that prepared transactions are reported as <code class="literal">in + progress</code>; applications must check <a class="link" href="view-pg-prepared-xacts.html" title="54.16. pg_prepared_xacts"><code class="structname">pg_prepared_xacts</code></a> + if they need to determine whether a transaction ID belongs to a + prepared transaction. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.31.2.2.4.1.1.1" class="indexterm"></a> + <code class="function">pg_current_snapshot</code> () + → <code class="returnvalue">pg_snapshot</code> + </p> + <p> + Returns a current <em class="firstterm">snapshot</em>, a data structure + showing which transaction IDs are now in-progress. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.31.2.2.5.1.1.1" class="indexterm"></a> + <code class="function">pg_snapshot_xip</code> ( <code class="type">pg_snapshot</code> ) + → <code class="returnvalue">setof xid8</code> + </p> + <p> + Returns the set of in-progress transaction IDs contained in a snapshot. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.31.2.2.6.1.1.1" class="indexterm"></a> + <code class="function">pg_snapshot_xmax</code> ( <code class="type">pg_snapshot</code> ) + → <code class="returnvalue">xid8</code> + </p> + <p> + Returns the <code class="structfield">xmax</code> of a snapshot. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.31.2.2.7.1.1.1" class="indexterm"></a> + <code class="function">pg_snapshot_xmin</code> ( <code class="type">pg_snapshot</code> ) + → <code class="returnvalue">xid8</code> + </p> + <p> + Returns the <code class="structfield">xmin</code> of a snapshot. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.31.2.2.8.1.1.1" class="indexterm"></a> + <code class="function">pg_visible_in_snapshot</code> ( <code class="type">xid8</code>, <code class="type">pg_snapshot</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + Is the given transaction ID <em class="firstterm">visible</em> according + to this snapshot (that is, was it completed before the snapshot was + taken)? Note that this function will not give the correct answer for + a subtransaction ID. + </p></td></tr></tbody></table></div></div><br class="table-break" /><p> + The internal transaction ID type <code class="type">xid</code> is 32 bits wide and + wraps around every 4 billion transactions. However, + the functions shown in <a class="xref" href="functions-info.html#FUNCTIONS-PG-SNAPSHOT" title="Table 9.78. Transaction ID and Snapshot Information Functions">Table 9.78</a> use a + 64-bit type <code class="type">xid8</code> that does not wrap around during the life + of an installation, and can be converted to <code class="type">xid</code> by casting if + required. The data type <code class="type">pg_snapshot</code> stores information about + transaction ID visibility at a particular moment in time. Its components + are described in <a class="xref" href="functions-info.html#FUNCTIONS-PG-SNAPSHOT-PARTS" title="Table 9.79. Snapshot Components">Table 9.79</a>. + <code class="type">pg_snapshot</code>'s textual representation is + <code class="literal"><em class="replaceable"><code>xmin</code></em>:<em class="replaceable"><code>xmax</code></em>:<em class="replaceable"><code>xip_list</code></em></code>. + For example <code class="literal">10:20:10,14,15</code> means + <code class="literal">xmin=10, xmax=20, xip_list=10, 14, 15</code>. + </p><div class="table" id="FUNCTIONS-PG-SNAPSHOT-PARTS"><p class="title"><strong>Table 9.79. Snapshot Components</strong></p><div class="table-contents"><table class="table" summary="Snapshot Components" border="1"><colgroup><col /><col /></colgroup><thead><tr><th>Name</th><th>Description</th></tr></thead><tbody><tr><td><code class="structfield">xmin</code></td><td> + Lowest transaction ID that was still active. All transaction IDs + less than <code class="structfield">xmin</code> are either committed and visible, + or rolled back and dead. + </td></tr><tr><td><code class="structfield">xmax</code></td><td> + One past the highest completed transaction ID. All transaction IDs + greater than or equal to <code class="structfield">xmax</code> had not yet + completed as of the time of the snapshot, and thus are invisible. + </td></tr><tr><td><code class="structfield">xip_list</code></td><td> + Transactions in progress at the time of the snapshot. A transaction + ID that is <code class="literal">xmin <= <em class="replaceable"><code>X</code></em> < + xmax</code> and not in this list was already completed at the time + of the snapshot, and thus is either visible or dead according to its + commit status. This list does not include the transaction IDs of + subtransactions. + </td></tr></tbody></table></div></div><br class="table-break" /><p> + In releases of <span class="productname">PostgreSQL</span> before 13 there was + no <code class="type">xid8</code> type, so variants of these functions were provided + that used <code class="type">bigint</code> to represent a 64-bit XID, with a + correspondingly distinct snapshot data type <code class="type">txid_snapshot</code>. + These older functions have <code class="literal">txid</code> in their names. They + are still supported for backward compatibility, but may be removed from a + future release. See <a class="xref" href="functions-info.html#FUNCTIONS-TXID-SNAPSHOT" title="Table 9.80. Deprecated Transaction ID and Snapshot Information Functions">Table 9.80</a>. + </p><div class="table" id="FUNCTIONS-TXID-SNAPSHOT"><p class="title"><strong>Table 9.80. Deprecated Transaction ID and Snapshot Information Functions</strong></p><div class="table-contents"><table class="table" summary="Deprecated Transaction ID and Snapshot Information Functions" border="1"><colgroup><col /></colgroup><thead><tr><th class="func_table_entry"><p class="func_signature"> + Function + </p> + <p> + Description + </p></th></tr></thead><tbody><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.35.2.2.1.1.1.1" class="indexterm"></a> + <code class="function">txid_current</code> () + → <code class="returnvalue">bigint</code> + </p> + <p> + See <code class="function">pg_current_xact_id()</code>. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.35.2.2.2.1.1.1" class="indexterm"></a> + <code class="function">txid_current_if_assigned</code> () + → <code class="returnvalue">bigint</code> + </p> + <p> + See <code class="function">pg_current_xact_id_if_assigned()</code>. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.35.2.2.3.1.1.1" class="indexterm"></a> + <code class="function">txid_current_snapshot</code> () + → <code class="returnvalue">txid_snapshot</code> + </p> + <p> + See <code class="function">pg_current_snapshot()</code>. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.35.2.2.4.1.1.1" class="indexterm"></a> + <code class="function">txid_snapshot_xip</code> ( <code class="type">txid_snapshot</code> ) + → <code class="returnvalue">setof bigint</code> + </p> + <p> + See <code class="function">pg_snapshot_xip()</code>. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.35.2.2.5.1.1.1" class="indexterm"></a> + <code class="function">txid_snapshot_xmax</code> ( <code class="type">txid_snapshot</code> ) + → <code class="returnvalue">bigint</code> + </p> + <p> + See <code class="function">pg_snapshot_xmax()</code>. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.35.2.2.6.1.1.1" class="indexterm"></a> + <code class="function">txid_snapshot_xmin</code> ( <code class="type">txid_snapshot</code> ) + → <code class="returnvalue">bigint</code> + </p> + <p> + See <code class="function">pg_snapshot_xmin()</code>. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.35.2.2.7.1.1.1" class="indexterm"></a> + <code class="function">txid_visible_in_snapshot</code> ( <code class="type">bigint</code>, <code class="type">txid_snapshot</code> ) + → <code class="returnvalue">boolean</code> + </p> + <p> + See <code class="function">pg_visible_in_snapshot()</code>. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.35.2.2.8.1.1.1" class="indexterm"></a> + <code class="function">txid_status</code> ( <code class="type">bigint</code> ) + → <code class="returnvalue">text</code> + </p> + <p> + See <code class="function">pg_xact_status()</code>. + </p></td></tr></tbody></table></div></div><br class="table-break" /><p> + The functions shown in <a class="xref" href="functions-info.html#FUNCTIONS-COMMIT-TIMESTAMP" title="Table 9.81. Committed Transaction Information Functions">Table 9.81</a> + provide information about when past transactions were committed. + They only provide useful data when the + <a class="xref" href="runtime-config-replication.html#GUC-TRACK-COMMIT-TIMESTAMP">track_commit_timestamp</a> configuration option is + enabled, and only for transactions that were committed after it was + enabled. + </p><div class="table" id="FUNCTIONS-COMMIT-TIMESTAMP"><p class="title"><strong>Table 9.81. Committed Transaction Information Functions</strong></p><div class="table-contents"><table class="table" summary="Committed Transaction Information Functions" border="1"><colgroup><col /></colgroup><thead><tr><th class="func_table_entry"><p class="func_signature"> + Function + </p> + <p> + Description + </p></th></tr></thead><tbody><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.37.2.2.1.1.1.1" class="indexterm"></a> + <code class="function">pg_xact_commit_timestamp</code> ( <code class="type">xid</code> ) + → <code class="returnvalue">timestamp with time zone</code> + </p> + <p> + Returns the commit timestamp of a transaction. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.37.2.2.2.1.1.1" class="indexterm"></a> + <code class="function">pg_xact_commit_timestamp_origin</code> ( <code class="type">xid</code> ) + → <code class="returnvalue">record</code> + ( <em class="parameter"><code>timestamp</code></em> <code class="type">timestamp with time zone</code>, + <em class="parameter"><code>roident</code></em> <code class="type">oid</code>) + </p> + <p> + Returns the commit timestamp and replication origin of a transaction. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.37.2.2.3.1.1.1" class="indexterm"></a> + <code class="function">pg_last_committed_xact</code> () + → <code class="returnvalue">record</code> + ( <em class="parameter"><code>xid</code></em> <code class="type">xid</code>, + <em class="parameter"><code>timestamp</code></em> <code class="type">timestamp with time zone</code>, + <em class="parameter"><code>roident</code></em> <code class="type">oid</code> ) + </p> + <p> + Returns the transaction ID, commit timestamp and replication origin + of the latest committed transaction. + </p></td></tr></tbody></table></div></div><br class="table-break" /><p> + The functions shown in <a class="xref" href="functions-info.html#FUNCTIONS-CONTROLDATA" title="Table 9.82. Control Data Functions">Table 9.82</a> + print information initialized during <code class="command">initdb</code>, such + as the catalog version. They also show information about write-ahead + logging and checkpoint processing. This information is cluster-wide, + not specific to any one database. These functions provide most of the same + information, from the same source, as the + <a class="xref" href="app-pgcontroldata.html" title="pg_controldata"><span class="refentrytitle"><span class="application">pg_controldata</span></span></a> application. + </p><div class="table" id="FUNCTIONS-CONTROLDATA"><p class="title"><strong>Table 9.82. Control Data Functions</strong></p><div class="table-contents"><table class="table" summary="Control Data Functions" border="1"><colgroup><col /></colgroup><thead><tr><th class="func_table_entry"><p class="func_signature"> + Function + </p> + <p> + Description + </p></th></tr></thead><tbody><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.39.2.2.1.1.1.1" class="indexterm"></a> + <code class="function">pg_control_checkpoint</code> () + → <code class="returnvalue">record</code> + </p> + <p> + Returns information about current checkpoint state, as shown in + <a class="xref" href="functions-info.html#FUNCTIONS-PG-CONTROL-CHECKPOINT" title="Table 9.83. pg_control_checkpoint Output Columns">Table 9.83</a>. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.39.2.2.2.1.1.1" class="indexterm"></a> + <code class="function">pg_control_system</code> () + → <code class="returnvalue">record</code> + </p> + <p> + Returns information about current control file state, as shown in + <a class="xref" href="functions-info.html#FUNCTIONS-PG-CONTROL-SYSTEM" title="Table 9.84. pg_control_system Output Columns">Table 9.84</a>. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.39.2.2.3.1.1.1" class="indexterm"></a> + <code class="function">pg_control_init</code> () + → <code class="returnvalue">record</code> + </p> + <p> + Returns information about cluster initialization state, as shown in + <a class="xref" href="functions-info.html#FUNCTIONS-PG-CONTROL-INIT" title="Table 9.85. pg_control_init Output Columns">Table 9.85</a>. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.32.39.2.2.4.1.1.1" class="indexterm"></a> + <code class="function">pg_control_recovery</code> () + → <code class="returnvalue">record</code> + </p> + <p> + Returns information about recovery state, as shown in + <a class="xref" href="functions-info.html#FUNCTIONS-PG-CONTROL-RECOVERY" title="Table 9.86. pg_control_recovery Output Columns">Table 9.86</a>. + </p></td></tr></tbody></table></div></div><br class="table-break" /><div class="table" id="FUNCTIONS-PG-CONTROL-CHECKPOINT"><p class="title"><strong>Table 9.83. <code class="function">pg_control_checkpoint</code> Output Columns</strong></p><div class="table-contents"><table class="table" summary="pg_control_checkpoint Output Columns" border="1"><colgroup><col /><col /></colgroup><thead><tr><th>Column Name</th><th>Data Type</th></tr></thead><tbody><tr><td><code class="structfield">checkpoint_lsn</code></td><td><code class="type">pg_lsn</code></td></tr><tr><td><code class="structfield">redo_lsn</code></td><td><code class="type">pg_lsn</code></td></tr><tr><td><code class="structfield">redo_wal_file</code></td><td><code class="type">text</code></td></tr><tr><td><code class="structfield">timeline_id</code></td><td><code class="type">integer</code></td></tr><tr><td><code class="structfield">prev_timeline_id</code></td><td><code class="type">integer</code></td></tr><tr><td><code class="structfield">full_page_writes</code></td><td><code class="type">boolean</code></td></tr><tr><td><code class="structfield">next_xid</code></td><td><code class="type">text</code></td></tr><tr><td><code class="structfield">next_oid</code></td><td><code class="type">oid</code></td></tr><tr><td><code class="structfield">next_multixact_id</code></td><td><code class="type">xid</code></td></tr><tr><td><code class="structfield">next_multi_offset</code></td><td><code class="type">xid</code></td></tr><tr><td><code class="structfield">oldest_xid</code></td><td><code class="type">xid</code></td></tr><tr><td><code class="structfield">oldest_xid_dbid</code></td><td><code class="type">oid</code></td></tr><tr><td><code class="structfield">oldest_active_xid</code></td><td><code class="type">xid</code></td></tr><tr><td><code class="structfield">oldest_multi_xid</code></td><td><code class="type">xid</code></td></tr><tr><td><code class="structfield">oldest_multi_dbid</code></td><td><code class="type">oid</code></td></tr><tr><td><code class="structfield">oldest_commit_ts_xid</code></td><td><code class="type">xid</code></td></tr><tr><td><code class="structfield">newest_commit_ts_xid</code></td><td><code class="type">xid</code></td></tr><tr><td><code class="structfield">checkpoint_time</code></td><td><code class="type">timestamp with time zone</code></td></tr></tbody></table></div></div><br class="table-break" /><div class="table" id="FUNCTIONS-PG-CONTROL-SYSTEM"><p class="title"><strong>Table 9.84. <code class="function">pg_control_system</code> Output Columns</strong></p><div class="table-contents"><table class="table" summary="pg_control_system Output Columns" border="1"><colgroup><col /><col /></colgroup><thead><tr><th>Column Name</th><th>Data Type</th></tr></thead><tbody><tr><td><code class="structfield">pg_control_version</code></td><td><code class="type">integer</code></td></tr><tr><td><code class="structfield">catalog_version_no</code></td><td><code class="type">integer</code></td></tr><tr><td><code class="structfield">system_identifier</code></td><td><code class="type">bigint</code></td></tr><tr><td><code class="structfield">pg_control_last_modified</code></td><td><code class="type">timestamp with time zone</code></td></tr></tbody></table></div></div><br class="table-break" /><div class="table" id="FUNCTIONS-PG-CONTROL-INIT"><p class="title"><strong>Table 9.85. <code class="function">pg_control_init</code> Output Columns</strong></p><div class="table-contents"><table class="table" summary="pg_control_init Output Columns" border="1"><colgroup><col /><col /></colgroup><thead><tr><th>Column Name</th><th>Data Type</th></tr></thead><tbody><tr><td><code class="structfield">max_data_alignment</code></td><td><code class="type">integer</code></td></tr><tr><td><code class="structfield">database_block_size</code></td><td><code class="type">integer</code></td></tr><tr><td><code class="structfield">blocks_per_segment</code></td><td><code class="type">integer</code></td></tr><tr><td><code class="structfield">wal_block_size</code></td><td><code class="type">integer</code></td></tr><tr><td><code class="structfield">bytes_per_wal_segment</code></td><td><code class="type">integer</code></td></tr><tr><td><code class="structfield">max_identifier_length</code></td><td><code class="type">integer</code></td></tr><tr><td><code class="structfield">max_index_columns</code></td><td><code class="type">integer</code></td></tr><tr><td><code class="structfield">max_toast_chunk_size</code></td><td><code class="type">integer</code></td></tr><tr><td><code class="structfield">large_object_chunk_size</code></td><td><code class="type">integer</code></td></tr><tr><td><code class="structfield">float8_pass_by_value</code></td><td><code class="type">boolean</code></td></tr><tr><td><code class="structfield">data_page_checksum_version</code></td><td><code class="type">integer</code></td></tr></tbody></table></div></div><br class="table-break" /><div class="table" id="FUNCTIONS-PG-CONTROL-RECOVERY"><p class="title"><strong>Table 9.86. <code class="function">pg_control_recovery</code> Output Columns</strong></p><div class="table-contents"><table class="table" summary="pg_control_recovery Output Columns" border="1"><colgroup><col /><col /></colgroup><thead><tr><th>Column Name</th><th>Data Type</th></tr></thead><tbody><tr><td><code class="structfield">min_recovery_end_lsn</code></td><td><code class="type">pg_lsn</code></td></tr><tr><td><code class="structfield">min_recovery_end_timeline</code></td><td><code class="type">integer</code></td></tr><tr><td><code class="structfield">backup_start_lsn</code></td><td><code class="type">pg_lsn</code></td></tr><tr><td><code class="structfield">backup_end_lsn</code></td><td><code class="type">pg_lsn</code></td></tr><tr><td><code class="structfield">end_of_backup_record_required</code></td><td><code class="type">boolean</code></td></tr></tbody></table></div></div><br class="table-break" /></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="functions-srf.html" title="9.25. Set Returning Functions">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="functions.html" title="Chapter 9. Functions and Operators">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="functions-admin.html" title="9.27. System Administration Functions">Next</a></td></tr><tr><td width="40%" align="left" valign="top">9.25. Set Returning Functions </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 15.4 Documentation">Home</a></td><td width="40%" align="right" valign="top"> 9.27. System Administration Functions</td></tr></table></div></body></html>
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