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<!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>51.80. pg_replication_slots</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 V1.79.1" /><link rel="prev" href="view-pg-replication-origin-status.html" title="51.79. pg_replication_origin_status" /><link rel="next" href="view-pg-roles.html" title="51.81. pg_roles" /></head><body id="docContent" class="container-fluid col-10"><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">51.80. <code xmlns="http://www.w3.org/1999/xhtml" class="structname">pg_replication_slots</code></th></tr><tr><td width="10%" align="left"><a accesskey="p" href="view-pg-replication-origin-status.html" title="51.79. pg_replication_origin_status">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="catalogs.html" title="Chapter 51. System Catalogs">Up</a></td><th width="60%" align="center">Chapter 51. System Catalogs</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 13.1 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="view-pg-roles.html" title="51.81. pg_roles">Next</a></td></tr></table><hr></hr></div><div class="sect1" id="VIEW-PG-REPLICATION-SLOTS"><div class="titlepage"><div><div><h2 class="title" style="clear: both">51.80. <code class="structname">pg_replication_slots</code></h2></div></div></div><a id="id-1.10.4.82.2" class="indexterm"></a><p>
   The <code class="structname">pg_replication_slots</code> view provides a listing
   of all replication slots that currently exist on the database cluster,
   along with their current state.
  </p><p>
   For more on replication slots,
   see <a class="xref" href="warm-standby.html#STREAMING-REPLICATION-SLOTS" title="26.2.6. Replication Slots">Section 26.2.6</a> and <a class="xref" href="logicaldecoding.html" title="Chapter 48. Logical Decoding">Chapter 48</a>.
  </p><div class="table" id="id-1.10.4.82.5"><p class="title"><strong>Table 51.81. <code class="structname">pg_replication_slots</code> Columns</strong></p><div class="table-contents"><table class="table" summary="pg_replication_slots Columns" border="1"><colgroup><col /></colgroup><thead><tr><th class="catalog_table_entry"><p class="column_definition">
       Column Type
      </p>
      <p>
       Description
      </p></th></tr></thead><tbody><tr><td class="catalog_table_entry"><p class="column_definition">
       <code class="structfield">slot_name</code> <code class="type">name</code>
      </p>
      <p>
       A unique, cluster-wide identifier for the replication slot
      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
       <code class="structfield">plugin</code> <code class="type">name</code>
      </p>
      <p>
       The base name of the shared object containing the output plugin this logical slot is using, or null for physical slots.
      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
       <code class="structfield">slot_type</code> <code class="type">text</code>
      </p>
      <p>
       The slot type: <code class="literal">physical</code> or <code class="literal">logical</code>
      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
       <code class="structfield">datoid</code> <code class="type">oid</code>
       (references <a class="link" href="catalog-pg-database.html" title="51.15. pg_database"><code class="structname">pg_database</code></a>.<code class="structfield">oid</code>)
      </p>
      <p>
       The OID of the database this slot is associated with, or
       null. Only logical slots have an associated database.
      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
       <code class="structfield">database</code> <code class="type">name</code>
       (references <a class="link" href="catalog-pg-database.html" title="51.15. pg_database"><code class="structname">pg_database</code></a>.<code class="structfield">datname</code>)
      </p>
      <p>
       The name of the database this slot is associated with, or
       null. Only logical slots have an associated database.
      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
       <code class="structfield">temporary</code> <code class="type">bool</code>
      </p>
      <p>
       True if this is a temporary replication slot. Temporary slots are
       not saved to disk and are automatically dropped on error or when
       the session has finished.
      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
       <code class="structfield">active</code> <code class="type">bool</code>
      </p>
      <p>
       True if this slot is currently actively being used
      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
       <code class="structfield">active_pid</code> <code class="type">int4</code>
      </p>
      <p>
       The process ID of the session using this slot if the slot
       is currently actively being used. <code class="literal">NULL</code> if
       inactive.
      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
       <code class="structfield">xmin</code> <code class="type">xid</code>
      </p>
      <p>
       The oldest transaction that this slot needs the database to
       retain.  <code class="literal">VACUUM</code> cannot remove tuples deleted
       by any later transaction.
      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
       <code class="structfield">catalog_xmin</code> <code class="type">xid</code>
      </p>
      <p>
       The oldest transaction affecting the system catalogs that this
       slot needs the database to retain.  <code class="literal">VACUUM</code> cannot
       remove catalog tuples deleted by any later transaction.
      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
       <code class="structfield">restart_lsn</code> <code class="type">pg_lsn</code>
      </p>
      <p>
       The address (<code class="literal">LSN</code>) of oldest WAL which still
       might be required by the consumer of this slot and thus won't be
       automatically removed during checkpoints unless this LSN
       gets behind more than <a class="xref" href="runtime-config-replication.html#GUC-MAX-SLOT-WAL-KEEP-SIZE">max_slot_wal_keep_size</a>
       from the current LSN.  <code class="literal">NULL</code>
       if the <code class="literal">LSN</code> of this slot has never been reserved.
      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
       <code class="structfield">confirmed_flush_lsn</code> <code class="type">pg_lsn</code>
      </p>
      <p>
       The address (<code class="literal">LSN</code>) up to which the logical
       slot's consumer has confirmed receiving data. Data older than this is
       not available anymore. <code class="literal">NULL</code> for physical slots.
      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
       <code class="structfield">wal_status</code> <code class="type">text</code>
      </p>
      <p>
       Availability of WAL files claimed by this slot.
       Possible values are:
       </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p><code class="literal">reserved</code> means that the claimed files
          are within <code class="varname">max_wal_size</code>.</p></li><li class="listitem"><p><code class="literal">extended</code> means
          that <code class="varname">max_wal_size</code> is exceeded but the files are
          still retained, either by the replication slot or
          by <code class="varname">wal_keep_size</code>.
         </p></li><li class="listitem"><p>
          <code class="literal">unreserved</code> means that the slot no longer
          retains the required WAL files and some of them are to be removed at
          the next checkpoint.  This state can return
          to <code class="literal">reserved</code> or <code class="literal">extended</code>.
         </p></li><li class="listitem"><p>
          <code class="literal">lost</code> means that some required WAL files have
          been removed and this slot is no longer usable.
         </p></li></ul></div><p>
       The last two states are seen only when
       <a class="xref" href="runtime-config-replication.html#GUC-MAX-SLOT-WAL-KEEP-SIZE">max_slot_wal_keep_size</a> is
       non-negative. If <code class="structfield">restart_lsn</code> is NULL, this
       field is null.
      </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
       <code class="structfield">safe_wal_size</code> <code class="type">int8</code>
      </p>
      <p>
       The number of bytes that can be written to WAL such that this slot
       is not in danger of getting in state "lost".  It is NULL for lost
       slots, as well as if <code class="varname">max_slot_wal_keep_size</code>
       is <code class="literal">-1</code>.
      </p></td></tr></tbody></table></div></div><br class="table-break" /></div><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navfooter"><hr></hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="view-pg-replication-origin-status.html" title="51.79. pg_replication_origin_status">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="catalogs.html" title="Chapter 51. System Catalogs">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="view-pg-roles.html" title="51.81. pg_roles">Next</a></td></tr><tr><td width="40%" align="left" valign="top">51.79. <code xmlns="http://www.w3.org/1999/xhtml" class="structname">pg_replication_origin_status</code> </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 13.1 Documentation">Home</a></td><td width="40%" align="right" valign="top"> 51.81. <code xmlns="http://www.w3.org/1999/xhtml" class="structname">pg_roles</code></td></tr></table></div></body></html>