path: root/doc/src/sgml/ref/create_publication.sgml

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doc/src/sgml/ref/create_publication.sgml
PostgreSQL documentation
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<refentry id="sql-createpublication">
 <indexterm zone="sql-createpublication">
  <primary>CREATE PUBLICATION</primary>
 </indexterm>

 <refmeta>
  <refentrytitle>CREATE PUBLICATION</refentrytitle>
  <manvolnum>7</manvolnum>
  <refmiscinfo>SQL - Language Statements</refmiscinfo>
 </refmeta>

 <refnamediv>
  <refname>CREATE PUBLICATION</refname>
  <refpurpose>define a new publication</refpurpose>
 </refnamediv>

 <refsynopsisdiv>
<synopsis>
CREATE PUBLICATION <replaceable class="parameter">name</replaceable>
    [ FOR ALL TABLES
      | FOR <replaceable class="parameter">publication_object</replaceable> [, ... ] ]
    [ WITH ( <replaceable class="parameter">publication_parameter</replaceable> [= <replaceable class="parameter">value</replaceable>] [, ... ] ) ]

<phrase>where <replaceable class="parameter">publication_object</replaceable> is one of:</phrase>

    TABLE [ ONLY ] <replaceable class="parameter">table_name</replaceable> [ * ] [ ( <replaceable class="parameter">column_name</replaceable> [, ... ] ) ] [ WHERE ( <replaceable class="parameter">expression</replaceable> ) ] [, ... ]
    TABLES IN SCHEMA { <replaceable class="parameter">schema_name</replaceable> | CURRENT_SCHEMA } [, ... ]
</synopsis>
 </refsynopsisdiv>

 <refsect1>
  <title>Description</title>

  <para>
   <command>CREATE PUBLICATION</command> adds a new publication
   into the current database.  The publication name must be distinct from
   the name of any existing publication in the current database.
  </para>

  <para>
   A publication is essentially a group of tables whose data changes are
   intended to be replicated through logical replication.  See
   <xref linkend="logical-replication-publication"/> for details about how
   publications fit into the logical replication setup.
   </para>
 </refsect1>

 <refsect1>
  <title>Parameters</title>

  <variablelist>
   <varlistentry>
    <term><replaceable class="parameter">name</replaceable></term>
    <listitem>
     <para>
      The name of the new publication.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><literal>FOR TABLE</literal></term>
    <listitem>
     <para>
      Specifies a list of tables to add to the publication.  If
      <literal>ONLY</literal> is specified before the table name, only
      that table is added to the publication.  If <literal>ONLY</literal> is not
      specified, the table and all its descendant tables (if any) are added.
      Optionally, <literal>*</literal> can be specified after the table name to
      explicitly indicate that descendant tables are included.
      This does not apply to a partitioned table, however.  The partitions of
      a partitioned table are always implicitly considered part of the
      publication, so they are never explicitly added to the publication.
     </para>

     <para>
      If the optional <literal>WHERE</literal> clause is specified, it defines a
      <firstterm>row filter</firstterm> expression. Rows for
      which the <replaceable class="parameter">expression</replaceable>
      evaluates to false or null will not be published. Note that parentheses
      are required around the expression. It has no effect on
      <literal>TRUNCATE</literal> commands.
     </para>

     <para>
      When a column list is specified, only the named columns are replicated.
      If no column list is specified, all columns of the table are replicated
      through this publication, including any columns added later. It has no
      effect on <literal>TRUNCATE</literal> commands. See
      <xref linkend="logical-replication-col-lists"/> for details about column
      lists.
     </para>

     <para>
      Only persistent base tables and partitioned tables can be part of a
      publication.  Temporary tables, unlogged tables, foreign tables,
      materialized views, and regular views cannot be part of a publication.
     </para>

     <para>
      Specifying a column list when the publication also publishes
      <literal>FOR TABLES IN SCHEMA</literal> is not supported.
     </para>

     <para>
      When a partitioned table is added to a publication, all of its existing
      and future partitions are implicitly considered to be part of the
      publication.  So, even operations that are performed directly on a
      partition are also published via publications that its ancestors are
      part of.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><literal>FOR ALL TABLES</literal></term>
    <listitem>
     <para>
      Marks the publication as one that replicates changes for all tables in
      the database, including tables created in the future.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><literal>FOR TABLES IN SCHEMA</literal></term>
    <listitem>
     <para>
      Marks the publication as one that replicates changes for all tables in
      the specified list of schemas, including tables created in the future.
     </para>

     <para>
      Specifying a schema when the publication also publishes a table with a
      column list is not supported.
     </para>

     <para>
      Only persistent base tables and partitioned tables present in the schema
      will be included as part of the publication.  Temporary tables, unlogged
      tables, foreign tables, materialized views, and regular views from the
      schema will not be part of the publication.
     </para>

     <para>
      When a partitioned table is published via schema level publication, all
      of its existing and future partitions are implicitly considered to be part of the
      publication, regardless of whether they are from the publication schema or not.
      So, even operations that are performed directly on a
      partition are also published via publications that its ancestors are
      part of.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><literal>WITH ( <replaceable class="parameter">publication_parameter</replaceable> [= <replaceable class="parameter">value</replaceable>] [, ... ] )</literal></term>
    <listitem>
     <para>
      This clause specifies optional parameters for a publication.  The
      following parameters are supported:

      <variablelist>
       <varlistentry>
        <term><literal>publish</literal> (<type>string</type>)</term>
        <listitem>
         <para>
          This parameter determines which DML operations will be published by
          the new publication to the subscribers.  The value is
          comma-separated list of operations.  The allowed operations are
          <literal>insert</literal>, <literal>update</literal>,
          <literal>delete</literal>, and <literal>truncate</literal>.
          The default is to publish all actions,
          and so the default value for this option is
          <literal>'insert, update, delete, truncate'</literal>.
         </para>
         <para>
          This parameter only affects DML operations. In particular, the initial
          data synchronization (see <xref linkend="logical-replication-snapshot"/>)
          for logical replication does not take this parameter into account when
          copying existing table data.
         </para>
        </listitem>
       </varlistentry>

       <varlistentry>
        <term><literal>publish_via_partition_root</literal> (<type>boolean</type>)</term>
        <listitem>
         <para>
          This parameter determines whether changes in a partitioned table (or
          on its partitions) contained in the publication will be published
          using the identity and schema of the partitioned table rather than
          that of the individual partitions that are actually changed; the
          latter is the default.  Enabling this allows the changes to be
          replicated into a non-partitioned table or a partitioned table
          consisting of a different set of partitions.
         </para>

         <para>
          This parameter also affects how row filters and column lists are
          chosen for partitions; see below for details.
         </para>

         <para>
          If this is enabled, <literal>TRUNCATE</literal> operations performed
          directly on partitions are not replicated.
         </para>
        </listitem>
       </varlistentry>
      </variablelist></para>
    </listitem>
   </varlistentry>

  </variablelist>
 </refsect1>

 <refsect1>
  <title>Notes</title>

  <para>
   If <literal>FOR TABLE</literal>, <literal>FOR ALL TABLES</literal> or
   <literal>FOR TABLES IN SCHEMA</literal> are not specified, then the
   publication starts out with an empty set of tables.  That is useful if
   tables or schemas are to be added later.
  </para>

  <para>
   The creation of a publication does not start replication.  It only defines
   a grouping and filtering logic for future subscribers.
  </para>

  <para>
   To create a publication, the invoking user must have the
   <literal>CREATE</literal> privilege for the current database.
   (Of course, superusers bypass this check.)
  </para>

  <para>
   To add a table to a publication, the invoking user must have ownership
   rights on the table.  The <command>FOR ALL TABLES</command> and
   <command>FOR TABLES IN SCHEMA</command> clauses require the invoking
   user to be a superuser.
  </para>

  <para>
   The tables added to a publication that publishes <command>UPDATE</command>
   and/or <command>DELETE</command> operations must have
   <literal>REPLICA IDENTITY</literal> defined.  Otherwise those operations will be
   disallowed on those tables.
  </para>

  <para>
   Any column list must include the <literal>REPLICA IDENTITY</literal> columns
   in order for <command>UPDATE</command> or <command>DELETE</command>
   operations to be published. There are no column list restrictions if the
   publication publishes only <command>INSERT</command> operations.
  </para>

  <para>
   A row filter expression (i.e., the <literal>WHERE</literal> clause) must contain only
   columns that are covered by the <literal>REPLICA IDENTITY</literal>, in
   order for <command>UPDATE</command> and <command>DELETE</command> operations
   to be published. For publication of <command>INSERT</command> operations,
   any column may be used in the <literal>WHERE</literal> expression. The
   row filter allows simple expressions that don't have
   user-defined functions, user-defined operators, user-defined types,
   user-defined collations, non-immutable built-in functions, or references to
   system columns.
  </para>

  <para>
   The row filter on a table becomes redundant if
   <literal>FOR TABLES IN SCHEMA</literal> is specified and the table
   belongs to the referred schema.
  </para>

  <para>
   For published partitioned tables, the row filter for each
   partition is taken from the published partitioned table if the
   publication parameter <literal>publish_via_partition_root</literal> is true,
   or from the partition itself if it is false (the default).
   See <xref linkend="logical-replication-row-filter"/> for details about row
   filters.
   Similarly, for published partitioned tables, the column list for each
   partition is taken from the published partitioned table if the
   publication parameter <literal>publish_via_partition_root</literal> is true,
   or from the partition itself if it is false.
  </para>

  <para>
   For an <command>INSERT ... ON CONFLICT</command> command, the publication will
   publish the operation that results from the command.  Depending
   on the outcome, it may be published as either <command>INSERT</command> or
   <command>UPDATE</command>, or it may not be published at all.
  </para>

  <para>
   For a <command>MERGE</command> command, the publication will publish an
   <command>INSERT</command>, <command>UPDATE</command>, or <command>DELETE</command>
   for each row inserted, updated, or deleted.
  </para>

  <para>
   <command>ATTACH</command>ing a table into a partition tree whose root is
   published using a publication with <literal>publish_via_partition_root</literal>
   set to <literal>true</literal> does not result in the table's existing contents
   being replicated.
  </para>

  <para>
   <command>COPY ... FROM</command> commands are published
   as <command>INSERT</command> operations.
  </para>

  <para>
   <acronym>DDL</acronym> operations are not published.
  </para>

  <para>
   The <literal>WHERE</literal> clause expression is executed with the role used
   for the replication connection.
  </para>
 </refsect1>

 <refsect1>
  <title>Examples</title>

  <para>
   Create a publication that publishes all changes in two tables:
<programlisting>
CREATE PUBLICATION mypublication FOR TABLE users, departments;
</programlisting>
  </para>

  <para>
   Create a publication that publishes all changes from active departments:
<programlisting>
CREATE PUBLICATION active_departments FOR TABLE departments WHERE (active IS TRUE);
</programlisting>
  </para>

  <para>
   Create a publication that publishes all changes in all tables:
<programlisting>
CREATE PUBLICATION alltables FOR ALL TABLES;
</programlisting>
  </para>

  <para>
   Create a publication that only publishes <command>INSERT</command>
   operations in one table:
<programlisting>
CREATE PUBLICATION insert_only FOR TABLE mydata
    WITH (publish = 'insert');
</programlisting>
  </para>

  <para>
   Create a publication that publishes all changes for tables
   <structname>users</structname>, <structname>departments</structname> and
   all changes for all the tables present in the schema
   <structname>production</structname>:
<programlisting>
CREATE PUBLICATION production_publication FOR TABLE users, departments, TABLES IN SCHEMA production;
</programlisting>
  </para>

  <para>
   Create a publication that publishes all changes for all the tables present in
   the schemas <structname>marketing</structname> and
   <structname>sales</structname>:
<programlisting>
CREATE PUBLICATION sales_publication FOR TABLES IN SCHEMA marketing, sales;
</programlisting></para>

  <para>
   Create a publication that publishes all changes for table <structname>users</structname>,
   but replicates only columns <structname>user_id</structname> and
   <structname>firstname</structname>:
<programlisting>
CREATE PUBLICATION users_filtered FOR TABLE users (user_id, firstname);
</programlisting></para>
 </refsect1>

 <refsect1>
  <title>Compatibility</title>

  <para>
   <command>CREATE PUBLICATION</command> is a <productname>PostgreSQL</productname>
   extension.
  </para>
 </refsect1>

 <refsect1>
  <title>See Also</title>

  <simplelist type="inline">
   <member><xref linkend="sql-alterpublication"/></member>
   <member><xref linkend="sql-droppublication"/></member>
   <member><xref linkend="sql-createsubscription"/></member>
   <member><xref linkend="sql-altersubscription"/></member>
  </simplelist>
 </refsect1>
</refentry>