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diff --git a/doc/src/sgml/html/upgrading.html b/doc/src/sgml/html/upgrading.html new file mode 100644 index 0000000..7cb184b --- /dev/null +++ b/doc/src/sgml/html/upgrading.html @@ -0,0 +1,195 @@ +<?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>19.6. Upgrading a PostgreSQL Cluster</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="server-shutdown.html" title="19.5. Shutting Down the Server" /><link rel="next" href="preventing-server-spoofing.html" title="19.7. Preventing Server Spoofing" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">19.6. Upgrading a <span class="productname">PostgreSQL</span> Cluster</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="server-shutdown.html" title="19.5. Shutting Down the Server">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="runtime.html" title="Chapter 19. Server Setup and Operation">Up</a></td><th width="60%" align="center">Chapter 19. Server Setup and Operation</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 15.5 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="preventing-server-spoofing.html" title="19.7. Preventing Server Spoofing">Next</a></td></tr></table><hr /></div><div class="sect1" id="UPGRADING"><div class="titlepage"><div><div><h2 class="title" style="clear: both">19.6. Upgrading a <span class="productname">PostgreSQL</span> Cluster</h2></div></div></div><div class="toc"><dl class="toc"><dt><span class="sect2"><a href="upgrading.html#UPGRADING-VIA-PGDUMPALL">19.6.1. Upgrading Data via <span class="application">pg_dumpall</span></a></span></dt><dt><span class="sect2"><a href="upgrading.html#UPGRADING-VIA-PG-UPGRADE">19.6.2. Upgrading Data via <span class="application">pg_upgrade</span></a></span></dt><dt><span class="sect2"><a href="upgrading.html#UPGRADING-VIA-REPLICATION">19.6.3. Upgrading Data via Replication</a></span></dt></dl></div><a id="id-1.6.6.9.2" class="indexterm"></a><a id="id-1.6.6.9.3" class="indexterm"></a><p> + This section discusses how to upgrade your database data from one + <span class="productname">PostgreSQL</span> release to a newer one. + </p><p> + Current <span class="productname">PostgreSQL</span> version numbers consist of a + major and a minor version number. For example, in the version number 10.1, + the 10 is the major version number and the 1 is the minor version number, + meaning this would be the first minor release of the major release 10. For + releases before <span class="productname">PostgreSQL</span> version 10.0, version + numbers consist of three numbers, for example, 9.5.3. In those cases, the + major version consists of the first two digit groups of the version number, + e.g., 9.5, and the minor version is the third number, e.g., 3, meaning this + would be the third minor release of the major release 9.5. + </p><p> + Minor releases never change the internal storage format and are always + compatible with earlier and later minor releases of the same major version + number. For example, version 10.1 is compatible with version 10.0 and + version 10.6. Similarly, for example, 9.5.3 is compatible with 9.5.0, + 9.5.1, and 9.5.6. To update between compatible versions, you simply + replace the executables while the server is down and restart the server. + The data directory remains unchanged — minor upgrades are that + simple. + </p><p> + For <span class="emphasis"><em>major</em></span> releases of <span class="productname">PostgreSQL</span>, the + internal data storage format is subject to change, thus complicating + upgrades. The traditional method for moving data to a new major version + is to dump and restore the database, though this can be slow. A + faster method is <a class="xref" href="pgupgrade.html" title="pg_upgrade"><span class="refentrytitle"><span class="application">pg_upgrade</span></span></a>. Replication methods are + also available, as discussed below. + (If you are using a pre-packaged version + of <span class="productname">PostgreSQL</span>, it may provide scripts to + assist with major version upgrades. Consult the package-level + documentation for details.) + </p><p> + New major versions also typically introduce some user-visible + incompatibilities, so application programming changes might be required. + All user-visible changes are listed in the release notes (<a class="xref" href="release.html" title="Appendix E. Release Notes">Appendix E</a>); pay particular attention to the section + labeled "Migration". Though you can upgrade from one major version + to another without upgrading to intervening versions, you should read + the major release notes of all intervening versions. + </p><p> + Cautious users will want to test their client applications on the new + version before switching over fully; therefore, it's often a good idea to + set up concurrent installations of old and new versions. When + testing a <span class="productname">PostgreSQL</span> major upgrade, consider the + following categories of possible changes: + </p><div class="variablelist"><dl class="variablelist"><dt><span class="term">Administration</span></dt><dd><p> + The capabilities available for administrators to monitor and control + the server often change and improve in each major release. + </p></dd><dt><span class="term">SQL</span></dt><dd><p> + Typically this includes new SQL command capabilities and not changes + in behavior, unless specifically mentioned in the release notes. + </p></dd><dt><span class="term">Library API</span></dt><dd><p> + Typically libraries like <span class="application">libpq</span> only add new + functionality, again unless mentioned in the release notes. + </p></dd><dt><span class="term">System Catalogs</span></dt><dd><p> + System catalog changes usually only affect database management tools. + </p></dd><dt><span class="term">Server C-language API</span></dt><dd><p> + This involves changes in the backend function API, which is written + in the C programming language. Such changes affect code that + references backend functions deep inside the server. + </p></dd></dl></div><div class="sect2" id="UPGRADING-VIA-PGDUMPALL"><div class="titlepage"><div><div><h3 class="title">19.6.1. Upgrading Data via <span class="application">pg_dumpall</span></h3></div></div></div><p> + One upgrade method is to dump data from one major version of + <span class="productname">PostgreSQL</span> and restore it in another — to do + this, you must use a <span class="emphasis"><em>logical</em></span> backup tool like + <span class="application">pg_dumpall</span>; file system + level backup methods will not work. (There are checks in place that prevent + you from using a data directory with an incompatible version of + <span class="productname">PostgreSQL</span>, so no great harm can be done by + trying to start the wrong server version on a data directory.) + </p><p> + It is recommended that you use the <span class="application">pg_dump</span> and + <span class="application">pg_dumpall</span> programs from the <span class="emphasis"><em>newer</em></span> + version of + <span class="productname">PostgreSQL</span>, to take advantage of enhancements + that might have been made in these programs. Current releases of the + dump programs can read data from any server version back to 9.2. + </p><p> + These instructions assume that your existing installation is under the + <code class="filename">/usr/local/pgsql</code> directory, and that the data area is in + <code class="filename">/usr/local/pgsql/data</code>. Substitute your paths + appropriately. + </p><div class="procedure"><ol class="procedure" type="1"><li class="step"><p> + If making a backup, make sure that your database is not being updated. + This does not affect the integrity of the backup, but the changed + data would of course not be included. If necessary, edit the + permissions in the file <code class="filename">/usr/local/pgsql/data/pg_hba.conf</code> + (or equivalent) to disallow access from everyone except you. + See <a class="xref" href="client-authentication.html" title="Chapter 21. Client Authentication">Chapter 21</a> for additional information on + access control. + </p><p> + <a id="id-1.6.6.9.11.5.1.2.1" class="indexterm"></a> + + To back up your database installation, type: +</p><pre class="screen"> +<strong class="userinput"><code>pg_dumpall > <em class="replaceable"><code>outputfile</code></em></code></strong> +</pre><p> + </p><p> + To make the backup, you can use the <span class="application">pg_dumpall</span> + command from the version you are currently running; see <a class="xref" href="backup-dump.html#BACKUP-DUMP-ALL" title="26.1.2. Using pg_dumpall">Section 26.1.2</a> for more details. For best + results, however, try to use the <span class="application">pg_dumpall</span> + command from <span class="productname">PostgreSQL</span> 15.5, + since this version contains bug fixes and improvements over older + versions. While this advice might seem idiosyncratic since you + haven't installed the new version yet, it is advisable to follow + it if you plan to install the new version in parallel with the + old version. In that case you can complete the installation + normally and transfer the data later. This will also decrease + the downtime. + </p></li><li class="step"><p> + Shut down the old server: +</p><pre class="screen"> +<strong class="userinput"><code>pg_ctl stop</code></strong> +</pre><p> + On systems that have <span class="productname">PostgreSQL</span> started at boot time, + there is probably a start-up file that will accomplish the same thing. For + example, on a <span class="systemitem">Red Hat Linux</span> system one + might find that this works: +</p><pre class="screen"> +<strong class="userinput"><code>/etc/rc.d/init.d/postgresql stop</code></strong> +</pre><p> + See <a class="xref" href="runtime.html" title="Chapter 19. Server Setup and Operation">Chapter 19</a> for details about starting and + stopping the server. + </p></li><li class="step"><p> + If restoring from backup, rename or delete the old installation + directory if it is not version-specific. It is a good idea to + rename the directory, rather than + delete it, in case you have trouble and need to revert to it. Keep + in mind the directory might consume significant disk space. To rename + the directory, use a command like this: +</p><pre class="screen"> +<strong class="userinput"><code>mv /usr/local/pgsql /usr/local/pgsql.old</code></strong> +</pre><p> + (Be sure to move the directory as a single unit so relative paths + remain unchanged.) + </p></li><li class="step"><p> + Install the new version of <span class="productname">PostgreSQL</span> as + outlined in <a class="xref" href="install-procedure.html" title="17.4. Installation Procedure">Section 17.4</a>. + </p></li><li class="step"><p> + Create a new database cluster if needed. Remember that you must + execute these commands while logged in to the special database user + account (which you already have if you are upgrading). +</p><pre class="programlisting"> +<strong class="userinput"><code>/usr/local/pgsql/bin/initdb -D /usr/local/pgsql/data</code></strong> +</pre><p> + </p></li><li class="step"><p> + Restore your previous <code class="filename">pg_hba.conf</code> and any + <code class="filename">postgresql.conf</code> modifications. + </p></li><li class="step"><p> + Start the database server, again using the special database user + account: +</p><pre class="programlisting"> +<strong class="userinput"><code>/usr/local/pgsql/bin/postgres -D /usr/local/pgsql/data</code></strong> +</pre><p> + </p></li><li class="step"><p> + Finally, restore your data from backup with: +</p><pre class="screen"> +<strong class="userinput"><code>/usr/local/pgsql/bin/psql -d postgres -f <em class="replaceable"><code>outputfile</code></em></code></strong> +</pre><p> + using the <span class="emphasis"><em>new</em></span> <span class="application">psql</span>. + </p></li></ol></div><p> + The least downtime can be achieved by installing the new server in + a different directory and running both the old and the new servers + in parallel, on different ports. Then you can use something like: + +</p><pre class="programlisting"> +pg_dumpall -p 5432 | psql -d postgres -p 5433 +</pre><p> + to transfer your data. + </p></div><div class="sect2" id="UPGRADING-VIA-PG-UPGRADE"><div class="titlepage"><div><div><h3 class="title">19.6.2. Upgrading Data via <span class="application">pg_upgrade</span></h3></div></div></div><p> + The <a class="xref" href="pgupgrade.html" title="pg_upgrade"><span class="refentrytitle"><span class="application">pg_upgrade</span></span></a> module allows an installation to + be migrated in-place from one major <span class="productname">PostgreSQL</span> + version to another. Upgrades can be performed in minutes, + particularly with <code class="option">--link</code> mode. It requires steps similar to + <span class="application">pg_dumpall</span> above, e.g., starting/stopping the server, + running <span class="application">initdb</span>. The <span class="application">pg_upgrade</span> <a class="link" href="pgupgrade.html" title="pg_upgrade">documentation</a> outlines the necessary steps. + </p></div><div class="sect2" id="UPGRADING-VIA-REPLICATION"><div class="titlepage"><div><div><h3 class="title">19.6.3. Upgrading Data via Replication</h3></div></div></div><p> + It is also possible to use logical replication methods to create a standby + server with the updated version of <span class="productname">PostgreSQL</span>. + This is possible because logical replication supports + replication between different major versions of + <span class="productname">PostgreSQL</span>. The standby can be on the same computer or + a different computer. Once it has synced up with the primary server + (running the older version of <span class="productname">PostgreSQL</span>), you can + switch primaries and make the standby the primary and shut down the older + database instance. Such a switch-over results in only several seconds + of downtime for an upgrade. + </p><p> + This method of upgrading can be performed using the built-in logical + replication facilities as well as using external logical replication + systems such as <span class="productname">pglogical</span>, + <span class="productname">Slony</span>, <span class="productname">Londiste</span>, and + <span class="productname">Bucardo</span>. + </p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="server-shutdown.html" title="19.5. Shutting Down the Server">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="runtime.html" title="Chapter 19. Server Setup and Operation">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="preventing-server-spoofing.html" title="19.7. Preventing Server Spoofing">Next</a></td></tr><tr><td width="40%" align="left" valign="top">19.5. 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