doc/src/sgml/ref/create_subscription.sgml - master - githubmirror/postgres

doc/src/sgml/ref/create_subscription.sgml
811 строк35 KB
Peter Eisentraut
doc: Make synopsis placeholders consistent
04 авг 2026, 15:56
04 авг 2026, 15:560e9a31b
<!--
doc/src/sgml/ref/create_subscription.sgml
PostgreSQL documentation
-->

<refentry id="sql-createsubscription">
 <indexterm zone="sql-createsubscription">
  <primary>CREATE SUBSCRIPTION</primary>
 </indexterm>

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

 <refnamediv>
  <refname>CREATE SUBSCRIPTION</refname>
  <refpurpose>define a new subscription</refpurpose>
 </refnamediv>

 <refsynopsisdiv>
<synopsis>
CREATE SUBSCRIPTION <replaceable class="parameter">subscription_name</replaceable>
    { SERVER <replaceable class="parameter">server_name</replaceable> | CONNECTION '<replaceable class="parameter">conninfo</replaceable>' }
    PUBLICATION <replaceable class="parameter">publication_name</replaceable> [, ...]
    [ WITH ( <replaceable class="parameter">subscription_parameter</replaceable> [= <replaceable class="parameter">value</replaceable>] [, ... ] ) ]
</synopsis>
 </refsynopsisdiv>

 <refsect1>
  <title>Description</title>

  <para>
   <command>CREATE SUBSCRIPTION</command> adds a new logical-replication
   subscription.  The user that creates a subscription becomes the owner
   of the subscription. The subscription name must be distinct from the name of
   any existing subscription in the current database.
  </para>

  <para>
   A subscription represents a replication connection to the publisher.
   Hence, in addition to adding definitions in the local catalogs, this
   command normally creates a replication slot on the publisher.
  </para>

  <para>
   A logical replication worker will be started to replicate data for the new
   subscription at the commit of the transaction where this command is run,
   unless the subscription is initially disabled.
  </para>

  <para>
   To be able to create a subscription, you must have the privileges of
   the <literal>pg_create_subscription</literal> role, as well as
   <literal>CREATE</literal> privileges on the current database.
  </para>

  <para>
   Additional information about subscriptions and logical replication as a
   whole is available at <xref linkend="logical-replication-subscription"/> and
   <xref linkend="logical-replication"/>.
  </para>

 </refsect1>

 <refsect1>
  <title>Parameters</title>

  <variablelist>
   <varlistentry id="sql-createsubscription-params-name">
    <term><replaceable class="parameter">subscription_name</replaceable></term>
    <listitem>
     <para>
      The name of the new subscription.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry id="sql-createsubscription-params-server">
    <term><literal>SERVER <replaceable class="parameter">server_name</replaceable></literal></term>
    <listitem>
     <para>
      A foreign server to use for the connection.  The server's foreign data
      wrapper must have a <replaceable>connection_function</replaceable>
      registered, and a user mapping for the subscription owner on the server
      must exist.  Additionally, the subscription owner must have
      <literal>USAGE</literal> privileges on
      <replaceable>server_name</replaceable>.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry id="sql-createsubscription-params-connection">
    <term><literal>CONNECTION '<replaceable class="parameter">conninfo</replaceable>'</literal></term>
    <listitem>
     <para>
      The <application>libpq</application> connection string defining how
      to connect to the publisher database.  For details see
      <xref linkend="libpq-connstring"/>.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry id="sql-createsubscription-params-publication">
    <term><literal>PUBLICATION <replaceable class="parameter">publication_name</replaceable> [, ...]</literal></term>
    <listitem>
     <para>
      Names of the publications on the publisher to subscribe to.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry id="sql-createsubscription-params-with">
    <term><literal>WITH ( <replaceable class="parameter">subscription_parameter</replaceable> [= <replaceable class="parameter">value</replaceable>] [, ... ] )</literal></term>
    <listitem>
     <para>
      This clause specifies optional parameters for a subscription.
     </para>

     <para>
      The following parameters control what happens during subscription creation:

      <variablelist>

       <varlistentry id="sql-createsubscription-params-with-connect">
        <term><literal>connect</literal> (<type>boolean</type>)</term>
        <listitem>
         <para>
          Specifies whether the <command>CREATE SUBSCRIPTION</command>
          command should connect to the publisher at all.  The default
          is <literal>true</literal>.  Setting this to
          <literal>false</literal> will force the values of
          <literal>create_slot</literal>, <literal>enabled</literal> and
          <literal>copy_data</literal> to <literal>false</literal>.
          (You cannot combine setting <literal>connect</literal>
          to <literal>false</literal> with
          setting <literal>create_slot</literal>, <literal>enabled</literal>,
          or <literal>copy_data</literal> to <literal>true</literal>.)
         </para>

         <para>
          Since no connection is made when this option is
          <literal>false</literal>, no tables and sequences are subscribed. To
          initiate replication, you must manually create the replication slot,
          enable the failover if required, enable the subscription, and refresh
          the subscription. See
          <xref linkend="logical-replication-subscription-examples-deferred-slot"/>
          for examples.
         </para>
        </listitem>
       </varlistentry>

       <varlistentry id="sql-createsubscription-params-with-create-slot">
        <term><literal>create_slot</literal> (<type>boolean</type>)</term>
        <listitem>
         <para>
          Specifies whether the command should create the replication slot on
          the publisher.  The default is <literal>true</literal>.
         </para>
         <para>
          If set to <literal>false</literal>, you are responsible for
          creating the publisher's slot in some other way. See
          <xref linkend="logical-replication-subscription-examples-deferred-slot"/>
          for examples.
         </para>
        </listitem>
       </varlistentry>

       <varlistentry id="sql-createsubscription-params-with-enabled">
        <term><literal>enabled</literal> (<type>boolean</type>)</term>
        <listitem>
         <para>
          Specifies whether the subscription should be actively replicating
          or whether it should just be set up but not started yet.  The default
          is <literal>true</literal>.
         </para>
        </listitem>
       </varlistentry>

       <varlistentry id="sql-createsubscription-params-with-slot-name">
        <term><literal>slot_name</literal> (<type>string</type>)</term>
        <listitem>
         <para>
          Name of the publisher's replication slot to use.  The default is
          to use the name of the subscription for the slot name. The name cannot
          be <literal>pg_conflict_detection</literal> as it is reserved for the
          conflict detection.
         </para>

         <para>
          Setting <literal>slot_name</literal> to <literal>NONE</literal>
          means there will be no replication slot associated with the
          subscription. Such subscriptions must also have both
          <literal>enabled</literal> and <literal>create_slot</literal> set to
          <literal>false</literal>.  Use this when you will be creating the
          replication slot later manually. See
          <xref linkend="logical-replication-subscription-examples-deferred-slot"/>
          for examples.
         </para>

         <para>
          When setting <literal>slot_name</literal> to a valid name and
          <literal>create_slot</literal> to <literal>false</literal>, the
          <literal>failover</literal> property value of the named slot may
          differ from the counterpart <literal>failover</literal> parameter
          specified in the subscription. Always ensure the slot property
          <literal>failover</literal> matches the counterpart parameter of the
          subscription and vice versa. Otherwise, the slot on the publisher may
          behave differently from what these subscription options say: for
          example, the slot on the publisher could either be synced to the
          standbys even when the subscription's <literal>failover</literal>
          option is disabled or could be disabled for sync even when the
          subscription's <literal>failover</literal> option is enabled.
         </para>
        </listitem>
       </varlistentry>
      </variablelist>
     </para>

     <para>
      The following parameters control the subscription's replication
      behavior after it has been created:

      <variablelist>

       <varlistentry id="sql-createsubscription-params-with-binary">
        <term><literal>binary</literal> (<type>boolean</type>)</term>
        <listitem>
         <para>
          Specifies whether the subscription will request the publisher to send
          the data in binary format (as opposed to text). The default is
          <literal>false</literal>. Any initial table synchronization copy
          (see <literal>copy_data</literal>) also uses the same format. Binary
          format can be faster than the text format, but it is less portable
          across machine architectures and <productname>PostgreSQL</productname>
          versions. Binary format is very data type specific; for example, it
          will not allow copying from a <type>smallint</type> column to an
          <type>integer</type> column, even though that would work fine in text
          format. Even when this option is enabled, only data types having binary
          send and receive functions will be transferred in binary. Note that
          the initial synchronization requires all data types to have binary
          send and receive functions, otherwise the synchronization will fail
          (see <xref linkend="sql-createtype"/> for more about send/receive
          functions). This parameter has no effect for sequences.
         </para>

         <para>
          When doing cross-version replication, it could be that the
          publisher has a binary send function for some data type, but the
          subscriber lacks a binary receive function for that type.  In
          such a case, data transfer will fail, and
          the <literal>binary</literal> option cannot be used.
         </para>

         <para>
          If the publisher is a <productname>PostgreSQL</productname> version
          before 16, then any initial table synchronization will use text format
          even if <literal>binary = true</literal>.
         </para>
        </listitem>
       </varlistentry>

       <varlistentry id="sql-createsubscription-params-with-conflict-log-destination">
        <term><literal>conflict_log_destination</literal> (<type>enum</type>)</term>
        <listitem>
         <para>
          Specifies the destination for recording logical replication conflicts.
          The available values are:
          <variablelist>
           <varlistentry>
            <term><literal>log</literal></term>
            <listitem>
             <para>
              Conflict details are recorded in the server log.
              This is the default behavior.
             </para>
            </listitem>
           </varlistentry>
           <varlistentry>
            <term><literal>table</literal></term>
            <listitem>
             <para>
              The system automatically creates a structured table named
              <literal>pg_conflict_log_&lt;subid&gt;</literal> in the
              <literal>pg_conflict</literal> schema. This allows for easy
              querying and analysis of conflicts.
             </para>
             <caution>
              <para>
               The conflict log table is strictly tied to the lifecycle of the
               subscription or the <literal>conflict_log_destination</literal> setting. If
               the subscription is dropped, or if the destination is changed to
               <literal>log</literal>, the table is <emphasis>dropped</emphasis>.
              </para>
             </caution>
            </listitem>
           </varlistentry>
           <varlistentry>
            <term><literal>all</literal></term>
            <listitem>
             <para>
              This is equivalent to configuring both destinations <literal>log</literal>
              and <literal>table</literal> together.
             </para>
            </listitem>
           </varlistentry>
          </variablelist>
         </para>
        </listitem>
       </varlistentry>

       <varlistentry id="sql-createsubscription-params-with-copy-data">
        <term><literal>copy_data</literal> (<type>boolean</type>)</term>
        <listitem>
         <para>
          Specifies whether to copy pre-existing data in the publications
          that are being subscribed to when the replication starts.
          The default is <literal>true</literal>.
         </para>
         <para>
          If the publications contain <literal>WHERE</literal> clauses, it
          will affect what data is copied. Refer to the
          <xref linkend="sql-createsubscription-notes" /> for details.
         </para>
         <para>
          See <xref linkend="sql-createsubscription-notes"/> for details of how
          <literal>copy_data = true</literal> can interact with the
          <literal>origin</literal> parameter.
         </para>
         <para>
          See <xref linkend="sequence-definition-mismatches"/>
          for recommendations on how to handle any warnings about sequence
          definition differences between the publisher and the subscriber,
          which might occur when <literal>copy_data = true</literal>.
         </para>
        </listitem>
       </varlistentry>

       <varlistentry id="sql-createsubscription-params-with-streaming">
        <term><literal>streaming</literal> (<type>enum</type>)</term>
        <listitem>
         <para>
          Specifies whether to enable streaming of in-progress transactions
          for this subscription.  The default value is <literal>parallel</literal>,
          meaning incoming changes are directly applied via one of the parallel
          apply workers, if available. If no parallel apply worker is free to
          handle streaming transactions then the changes are written to
          temporary files and applied after the transaction is committed. Note
          that if an error happens in a parallel apply worker, the finish LSN
          of the remote transaction might not be reported in the server log.
          This parameter has no effect for sequences.
         </para>

         <caution>
          <para>
           There is a risk of deadlock when the schemas of the publisher and
           subscriber differ, although such cases are rare. The apply worker
           is equipped to retry these transactions automatically.
          </para>
         </caution>

         <para>
          If set to <literal>on</literal>, the incoming changes are written to
          temporary files and then applied only after the transaction is
          committed on the publisher and received by the subscriber.
         </para>

         <para>
          If set to <literal>off</literal>, all transactions are fully decoded
          on the publisher and only then sent to the subscriber as a whole.
         </para>
        </listitem>
       </varlistentry>

       <varlistentry id="sql-createsubscription-params-with-synchronous-commit">
        <term><literal>synchronous_commit</literal> (<type>enum</type>)</term>
        <listitem>
         <para>
          The value of this parameter overrides the
          <xref linkend="guc-synchronous-commit"/> setting within this
          subscription's apply worker processes.  The default value
          is <literal>off</literal>. This parameter has no effect for
          sequences.
         </para>

         <para>
          It is safe to use <literal>off</literal> for logical replication:
          If the subscriber loses transactions because of missing
          synchronization, the data will be sent again from the publisher.
         </para>

         <para>
          A different setting might be appropriate when doing synchronous
          logical replication.  The logical replication workers report the
          positions of writes and flushes to the publisher, and when using
          synchronous replication, the publisher will wait for the actual
          flush.  This means that setting
          <literal>synchronous_commit</literal> for the subscriber to
          <literal>off</literal> when the subscription is used for
          synchronous replication might increase the latency for
          <command>COMMIT</command> on the publisher.  In this scenario, it
          can be advantageous to set <literal>synchronous_commit</literal>
          to <literal>local</literal> or higher.
         </para>
        </listitem>
       </varlistentry>

       <varlistentry id="sql-createsubscription-params-with-two-phase">
        <term><literal>two_phase</literal> (<type>boolean</type>)</term>
        <listitem>
         <para>
          Specifies whether two-phase commit is enabled for this subscription.
          The default is <literal>false</literal>. This parameter has no effect
          for sequences.
         </para>

         <para>
          When two-phase commit is enabled, prepared transactions are sent
          to the subscriber at the time of <command>PREPARE
          TRANSACTION</command>, and are processed as two-phase
          transactions on the subscriber too.  Otherwise, prepared
          transactions are sent to the subscriber only when committed, and
          are then processed immediately by the subscriber.
         </para>

         <para>
          The implementation of two-phase commit requires that replication
          has successfully finished the initial table synchronization
          phase. So even when <literal>two_phase</literal> is enabled for a
          subscription, the internal two-phase state remains
          temporarily <quote>pending</quote> until the initialization phase
          completes. See column <structfield>subtwophasestate</structfield>
          of <link linkend="catalog-pg-subscription"><structname>pg_subscription</structname></link>
          to know the actual two-phase state.
         </para>

        </listitem>
       </varlistentry>

       <varlistentry id="sql-createsubscription-params-with-disable-on-error">
        <term><literal>disable_on_error</literal> (<type>boolean</type>)</term>
        <listitem>
         <para>
          Specifies whether the subscription should be automatically disabled
          if any errors are detected by subscription workers during data
          replication from the publisher. The default is
          <literal>false</literal>.
         </para>
        </listitem>
       </varlistentry>

       <varlistentry id="sql-createsubscription-params-with-password-required">
        <term><literal>password_required</literal> (<type>boolean</type>)</term>
        <listitem>
         <para>
          If set to <literal>true</literal>, connections to the publisher made
          as a result of this subscription must use password authentication
          and the password must be specified as a part of the connection
          string. This setting is ignored when the subscription is owned by a
          superuser.  The default is <literal>true</literal>. Only superusers
          can set this value to <literal>false</literal>.
         </para>
        </listitem>
       </varlistentry>

       <varlistentry id="sql-createsubscription-params-with-run-as-owner">
        <term><literal>run_as_owner</literal> (<type>boolean</type>)</term>
        <listitem>
         <para>
          If true, all replication actions are performed as the subscription
          owner. If false, replication workers will perform actions on each
          table or sequence as the owner of that relation. The latter
          configuration is generally much more secure; for details, see
          <xref linkend="logical-replication-security" />.
          The default is <literal>false</literal>.
         </para>
        </listitem>
       </varlistentry>

       <varlistentry id="sql-createsubscription-params-with-origin">
        <term><literal>origin</literal> (<type>string</type>)</term>
        <listitem>
         <para>
          Specifies whether the subscription will request the publisher to only
          send changes that don't have an origin or send changes regardless of
          origin. Setting <literal>origin</literal> to <literal>none</literal>
          means that the subscription will request the publisher to only send
          changes that don't have an origin. Setting <literal>origin</literal>
          to <literal>any</literal> means that the publisher sends changes
          regardless of their origin. The default is <literal>any</literal>.
          This parameter has no effect for sequences.
         </para>
         <para>
          See <xref linkend="sql-createsubscription-notes"/> for details of how
          <literal>copy_data = true</literal> can interact with the
          <literal>origin</literal> parameter.
         </para>
        </listitem>
       </varlistentry>

       <varlistentry id="sql-createsubscription-params-with-failover">
        <term><literal>failover</literal> (<type>boolean</type>)</term>
        <listitem>
         <para>
          Specifies whether the replication slots associated with the subscription
          are enabled to be synced to the standbys so that logical
          replication can be resumed from the new primary after failover.
          The default is <literal>false</literal>.
         </para>
        </listitem>
       </varlistentry>

      <varlistentry id="sql-createsubscription-params-with-retain-dead-tuples">
        <term><literal>retain_dead_tuples</literal> (<type>boolean</type>)</term>
        <listitem>
         <para>
          Specifies whether the information (e.g., dead tuples, commit
          timestamps, and origins) required for conflict detection on the
          subscriber is retained. The default is <literal>false</literal>.
          If set to <literal>true</literal>, the detection of
          <xref linkend="conflict-update-deleted"/> is enabled, and a physical
          replication slot named <quote><literal>pg_conflict_detection</literal></quote>
          is created on the subscriber to prevent the information for detecting
          conflicts from being removed. This parameter has no effect for
          sequences.
         </para>

         <para>
          Note that the information useful for conflict detection is retained
          only after the creation of the slot. You can verify the existence of
          this slot by querying <link linkend="view-pg-replication-slots">pg_replication_slots</link>.
          And even if multiple subscriptions on one node enable this option,
          only one replication slot will be created. Also,
          <varname>wal_level</varname> must be set to <literal>replica</literal>
          or higher to allow the replication slot to be used.
         </para>

         <caution>
          <para>
           Note that the information for conflict detection cannot be purged if
           the subscription is disabled; thus, the information will accumulate
           until the subscription is enabled. To prevent excessive accumulation,
           it is recommended to disable <literal>retain_dead_tuples</literal>
           if the subscription will be inactive for an extended period.
          </para>

          <para>
           Additionally when enabling <literal>retain_dead_tuples</literal> for
           conflict detection in logical replication, it is important to design the
           replication topology to balance data retention requirements with
           overall system performance. This option provides minimal performance
           overhead when applied appropriately. The following scenarios illustrate
           effective usage patterns when enabling this option.
          </para>

          <para>
           a. Large Tables with Bidirectional Writes:
           For large tables subject to concurrent writes on both publisher and
           subscriber nodes, publishers can define row filters when creating
           publications to segment data. This allows multiple subscriptions
           to replicate exclusive subsets of the table in parallel, optimizing
           the throughput.
          </para>

          <para>
           b. Write-Enabled Subscribers:
           If a subscriber node is expected to perform write operations, replication
           can be structured using multiple publications and subscriptions. By
           distributing tables across these publications, the workload is spread among
           several apply workers, improving concurrency and reducing contention.
          </para>

          <para>
           c. Read-Only Subscribers:
           In configurations involving single or multiple publisher nodes
           performing concurrent write operations, read-only subscriber nodes may
           replicate changes without seeing a performance impact if it does index
           scan. However, if the subscriber is impacted due to replication lag or
           scan performance (say due to sequential scans), it needs to follow one
           of the two previous strategies to distribute the workload on the
           subscriber.
          </para>
         </caution>

         <para>
          This option cannot be enabled if the publisher is a physical standby.
         </para>

         <para>
          Enabling this option ensures retention of information useful for
          conflict detection solely for changes occurring locally on the
          publisher. For the changes originating from different origins,
          reliable conflict detection cannot be guaranteed.
         </para>
        </listitem>
       </varlistentry>

       <varlistentry id="sql-createsubscription-params-with-max-retention-duration">
        <term><literal>max_retention_duration</literal> (<type>integer</type>)</term>
        <listitem>
         <para>
          Maximum duration in milliseconds for which this subscription's apply worker
          is allowed to retain the information useful for conflict detection when
          <literal>retain_dead_tuples</literal> is enabled. The default value
          is <literal>0</literal>, indicating that the information is retained
          until it is no longer needed for detection purposes.
         </para>
         <para>
          The information useful for conflict detection is no longer retained if
          all apply workers associated with the subscriptions, where
          <literal>retain_dead_tuples</literal> is enabled, confirm that the
          retention duration has exceeded the
          <literal>max_retention_duration</literal> set within the corresponding
          subscription. The retention will automatically resume when at least one
          apply worker confirms that the retention duration is within the
          specified limit, or when a new subscription is created with
          <literal>retain_dead_tuples = true</literal>. Alternatively, retention
          can be manually resumed by re-enabling <literal>retain_dead_tuples</literal>.
         </para>
         <para>
          Note that overall retention will not stop if other subscriptions that
          have a value greater than 0 for this parameter have not exceeded it,
          or if they set this option to 0.
         </para>
         <para>
          This option is effective only when
          <literal>retain_dead_tuples</literal> is enabled and the apply
          worker associated with the subscription is active.
         </para>
         <warning>
          <para>
           Note that setting a non-zero value for this option could lead to
           information for conflict detection being removed prematurely,
           potentially resulting in incorrect conflict detection.
          </para>
         </warning>
        </listitem>
       </varlistentry>

      <varlistentry id="sql-createsubscription-params-with-wal-receiver-timeout">
        <term><literal>wal_receiver_timeout</literal> (<type>text</type>)</term>
        <listitem>
         <para>
          The value of this parameter overrides the
          <xref linkend="guc-wal-receiver-timeout"/> setting within this
          subscription's apply worker processes.  The default value is
          <literal>-1</literal>, which means it does not override the global setting,
          i.e., the value from the server configuration, command line, role or
          database settings will be used instead.
         </para>
        </listitem>
       </varlistentry>
      </variablelist></para>
    </listitem>
   </varlistentry>
  </variablelist>

  <para>
   When specifying a parameter of type <type>boolean</type>, the
   <literal>=</literal> <replaceable class="parameter">value</replaceable>
   part can be omitted, which is equivalent to
   specifying <literal>TRUE</literal>.
  </para>
 </refsect1>

 <refsect1 id="sql-createsubscription-notes" xreflabel="Notes">
  <title>Notes</title>

  <para>
   See <xref linkend="logical-replication-security"/> for details on
   how to configure access control between the subscription and the
   publication instance.
  </para>

  <para>
   When creating a replication slot (the default behavior), <command>CREATE
   SUBSCRIPTION</command> cannot be executed inside a transaction block.
  </para>

  <para>
   Creating a subscription that connects to the same database cluster (for
   example, to replicate between databases in the same cluster or to replicate
   within the same database) will only succeed if the replication slot is not
   created as part of the same command.  Otherwise, the <command>CREATE
   SUBSCRIPTION</command> call will hang.  To make this work, create the
   replication slot separately (using the
   function <function>pg_create_logical_replication_slot</function> with the
   plugin name <literal>pgoutput</literal>) and create the subscription using
   the parameter <literal>create_slot = false</literal>.  See
   <xref linkend="logical-replication-subscription-examples-deferred-slot"/>
   for examples. This is an implementation restriction that might be lifted in a
   future release.
  </para>

  <para>
   If any table in the publication has a <literal>WHERE</literal> clause, rows
   for which the <replaceable class="parameter">expression</replaceable>
   evaluates to <literal>false</literal> or <literal>NULL</literal> will not be
   published. If the subscription has
   several publications in which the same table has been published with
   different <literal>WHERE</literal> clauses, a row will be published if any
   of the expressions (referring to that publish operation) are satisfied. In
   the case of different <literal>WHERE</literal> clauses, if one of the
   publications has no <literal>WHERE</literal> clause (referring to that
   publish operation) or the publication is declared as
   <link linkend="sql-createpublication-params-for-all-tables"><literal>FOR ALL TABLES</literal></link>
   or <link linkend="sql-createpublication-params-for-tables-in-schema"><literal>FOR TABLES IN SCHEMA</literal></link>,
   rows are always published regardless of the definition of the other
   expressions. If the subscriber is a <productname>PostgreSQL</productname>
   version before 15, then any row filtering is ignored during the initial data
   synchronization phase. For this case, the user might want to consider
   deleting any initially copied data that would be incompatible with
   subsequent filtering. Because initial data synchronization does not take
   into account the publication
   <link linkend="sql-createpublication-params-with-publish"><literal>publish</literal></link>
   parameter when copying existing table data, some rows may be copied that
   would not be replicated using DML. See
   <xref linkend="logical-replication-subscription-examples"/> for examples.
  </para>

  <para>
   Subscriptions having several publications in which the same table has been
   published with different column lists are not supported.
  </para>

  <para>
   We allow non-existent publications to be specified so that users can add
   those later. This means
   <link linkend="catalog-pg-subscription"><structname>pg_subscription</structname></link>
   can have non-existent publications.
  </para>

  <para>
   When using a subscription parameter combination of
   <literal>copy_data = true</literal> and <literal>origin = NONE</literal>,
   the initial sync table data is copied directly from the publisher, meaning
   that knowledge of the true origin of that data is not possible. If the
   publisher also has subscriptions then the copied table data might have
   originated from further upstream. This scenario is detected and a WARNING is
   logged to the user, but the warning is only an indication of a potential
   problem; it is the user's responsibility to make the necessary checks to
   ensure the copied data origins are really as wanted or not.
  </para>

  <para>
   To find which tables might potentially include non-local origins (due to
   other subscriptions created on the publisher) try this SQL query:
<programlisting>
# substitute &lt;pub-names&gt; below with your publication name(s) to be queried
SELECT DISTINCT PT.schemaname, PT.tablename
FROM pg_publication_tables PT
     JOIN pg_class C ON (C.relname = PT.tablename)
     JOIN pg_namespace N ON (N.nspname = PT.schemaname),
     pg_subscription_rel PS
WHERE C.relnamespace = N.oid AND
      (PS.srrelid = C.oid OR
      C.oid IN (SELECT relid FROM pg_partition_ancestors(PS.srrelid) UNION
                SELECT relid FROM pg_partition_tree(PS.srrelid))) AND
      PT.pubname IN (&lt;pub-names&gt;);
</programlisting></para>

 </refsect1>

 <refsect1>
  <title>Examples</title>

  <para>
   Create a subscription to a remote server that replicates tables in
   the publications <literal>mypublication</literal> and
   <literal>insert_only</literal> and starts replicating immediately on
   commit:
<programlisting>
CREATE SUBSCRIPTION mysub
         CONNECTION 'host=192.168.1.50 port=5432 user=foo dbname=foodb'
        PUBLICATION mypublication, insert_only;
</programlisting>
  </para>

  <para>
   Create a subscription to a remote server that replicates tables in
   the <literal>insert_only</literal> publication and does not start replicating
   until enabled at a later time.
<programlisting>
CREATE SUBSCRIPTION mysub
         CONNECTION 'host=192.168.1.50 port=5432 user=foo dbname=foodb'
        PUBLICATION insert_only
               WITH (enabled = false);
</programlisting></para>
 </refsect1>

 <refsect1>
  <title>Compatibility</title>

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

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

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