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   2 <!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>53.20. 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 Vsnapshot" /><link rel="prev" href="view-pg-replication-origin-status.html" title="53.19. pg_replication_origin_status" /><link rel="next" href="view-pg-roles.html" title="53.21. pg_roles" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">53.20. <code 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="53.19. pg_replication_origin_status">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="views.html" title="Chapter 53. System Views">Up</a></td><th width="60%" align="center">Chapter 53. System Views</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 18.0 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="view-pg-roles.html" title="53.21. pg_roles">Next</a></td></tr></table><hr /></div><div class="sect1" id="VIEW-PG-REPLICATION-SLOTS"><div class="titlepage"><div><div><h2 class="title" style="clear: both">53.20. <code class="structname">pg_replication_slots</code> <a href="#VIEW-PG-REPLICATION-SLOTS" class="id_link">#</a></h2></div></div></div><a id="id-1.10.5.24.2" class="indexterm"></a><p>
   3    The <code class="structname">pg_replication_slots</code> view provides a listing
   4    of all replication slots that currently exist on the database cluster,
   5    along with their current state.
   6   </p><p>
   7    For more on replication slots,
   8    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 47. Logical Decoding">Chapter 47</a>.
   9   </p><div class="table" id="id-1.10.5.24.5"><p class="title"><strong>Table 53.20. <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">
  10        Column Type
  11       </p>
  12       <p>
  13        Description
  14       </p></th></tr></thead><tbody><tr><td class="catalog_table_entry"><p class="column_definition">
  15        <code class="structfield">slot_name</code> <code class="type">name</code>
  16       </p>
  17       <p>
  18        A unique, cluster-wide identifier for the replication slot
  19       </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
  20        <code class="structfield">plugin</code> <code class="type">name</code>
  21       </p>
  22       <p>
  23        The base name of the shared object containing the output plugin this logical slot is using, or null for physical slots.
  24       </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
  25        <code class="structfield">slot_type</code> <code class="type">text</code>
  26       </p>
  27       <p>
  28        The slot type: <code class="literal">physical</code> or <code class="literal">logical</code>
  29       </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
  30        <code class="structfield">datoid</code> <code class="type">oid</code>
  31        (references <a class="link" href="catalog-pg-database.html" title="52.15. pg_database"><code class="structname">pg_database</code></a>.<code class="structfield">oid</code>)
  32       </p>
  33       <p>
  34        The OID of the database this slot is associated with, or
  35        null. Only logical slots have an associated database.
  36       </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
  37        <code class="structfield">database</code> <code class="type">name</code>
  38        (references <a class="link" href="catalog-pg-database.html" title="52.15. pg_database"><code class="structname">pg_database</code></a>.<code class="structfield">datname</code>)
  39       </p>
  40       <p>
  41        The name of the database this slot is associated with, or
  42        null. Only logical slots have an associated database.
  43       </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
  44        <code class="structfield">temporary</code> <code class="type">bool</code>
  45       </p>
  46       <p>
  47        True if this is a temporary replication slot. Temporary slots are
  48        not saved to disk and are automatically dropped on error or when
  49        the session has finished.
  50       </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
  51        <code class="structfield">active</code> <code class="type">bool</code>
  52       </p>
  53       <p>
  54        True if this slot is currently being streamed
  55       </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
  56        <code class="structfield">active_pid</code> <code class="type">int4</code>
  57       </p>
  58       <p>
  59        The process ID of the session streaming data for this slot.
  60        <code class="literal">NULL</code> if inactive.
  61       </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
  62        <code class="structfield">xmin</code> <code class="type">xid</code>
  63       </p>
  64       <p>
  65        The oldest transaction that this slot needs the database to
  66        retain.  <code class="literal">VACUUM</code> cannot remove tuples deleted
  67        by any later transaction.
  68       </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
  69        <code class="structfield">catalog_xmin</code> <code class="type">xid</code>
  70       </p>
  71       <p>
  72        The oldest transaction affecting the system catalogs that this
  73        slot needs the database to retain.  <code class="literal">VACUUM</code> cannot
  74        remove catalog tuples deleted by any later transaction.
  75       </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
  76        <code class="structfield">restart_lsn</code> <code class="type">pg_lsn</code>
  77       </p>
  78       <p>
  79        The address (<code class="literal">LSN</code>) of oldest WAL which still
  80        might be required by the consumer of this slot and thus won't be
  81        automatically removed during checkpoints unless this LSN
  82        gets behind more than <a class="xref" href="runtime-config-replication.html#GUC-MAX-SLOT-WAL-KEEP-SIZE">max_slot_wal_keep_size</a>
  83        from the current LSN.  <code class="literal">NULL</code>
  84        if the <code class="literal">LSN</code> of this slot has never been reserved.
  85       </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
  86        <code class="structfield">confirmed_flush_lsn</code> <code class="type">pg_lsn</code>
  87       </p>
  88       <p>
  89        The address (<code class="literal">LSN</code>) up to which the logical
  90        slot's consumer has confirmed receiving data. Data corresponding to the
  91        transactions committed before this <code class="literal">LSN</code> is not
  92        available anymore. <code class="literal">NULL</code> for physical slots.
  93       </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
  94        <code class="structfield">wal_status</code> <code class="type">text</code>
  95       </p>
  96       <p>
  97        Availability of WAL files claimed by this slot.
  98        Possible values are:
  99        </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
 100           are within <code class="varname">max_wal_size</code>.</p></li><li class="listitem"><p><code class="literal">extended</code> means
 101           that <code class="varname">max_wal_size</code> is exceeded but the files are
 102           still retained, either by the replication slot or
 103           by <code class="varname">wal_keep_size</code>.
 104          </p></li><li class="listitem"><p>
 105           <code class="literal">unreserved</code> means that the slot no longer
 106           retains the required WAL files and some of them are to be removed at
 107           the next checkpoint.  This typically occurs when
 108           <a class="xref" href="runtime-config-replication.html#GUC-MAX-SLOT-WAL-KEEP-SIZE">max_slot_wal_keep_size</a> is set to
 109           a non-negative value.  This state can return
 110           to <code class="literal">reserved</code> or <code class="literal">extended</code>.
 111          </p></li><li class="listitem"><p>
 112           <code class="literal">lost</code> means that this slot is no longer usable.
 113          </p></li></ul></div><p>
 114       </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
 115        <code class="structfield">safe_wal_size</code> <code class="type">int8</code>
 116       </p>
 117       <p>
 118        The number of bytes that can be written to WAL such that this slot
 119        is not in danger of getting in state "lost".  It is NULL for lost
 120        slots, as well as if <code class="varname">max_slot_wal_keep_size</code>
 121        is <code class="literal">-1</code>.
 122       </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
 123        <code class="structfield">two_phase</code> <code class="type">bool</code>
 124       </p>
 125       <p>
 126        True if the slot is enabled for decoding prepared transactions.  Always
 127        false for physical slots.
 128       </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
 129        <code class="structfield">two_phase_at</code> <code class="type">pg_lsn</code>
 130       </p>
 131       <p>
 132        The address (<code class="literal">LSN</code>) from which the decoding of prepared
 133        transactions is enabled. <code class="literal">NULL</code> for logical slots
 134        where <code class="structfield">two_phase</code> is false and for physical slots.
 135       </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
 136        <code class="structfield">inactive_since</code> <code class="type">timestamptz</code>
 137       </p>
 138       <p>
 139         The time when the slot became inactive. <code class="literal">NULL</code> if the
 140         slot is currently being streamed. If the slot becomes invalid,
 141         this value will never be updated.
 142         For standby slots that are being synced from a
 143         primary server (whose <code class="structfield">synced</code> field is
 144         <code class="literal">true</code>), the <code class="structfield">inactive_since</code>
 145         indicates the time when slot synchronization (see <a class="xref" href="logicaldecoding-explanation.html#LOGICALDECODING-REPLICATION-SLOTS-SYNCHRONIZATION" title="47.2.3. Replication Slot Synchronization">Section 47.2.3</a>)
 146         was most recently stopped.  <code class="literal">NULL</code> if the slot
 147         has always been synchronized. This helps standby slots track when
 148         synchronization was interrupted.
 149       </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
 150        <code class="structfield">conflicting</code> <code class="type">bool</code>
 151       </p>
 152       <p>
 153        True if this logical slot conflicted with recovery (and so is now
 154        invalidated). When this column is true, check
 155        <code class="structfield">invalidation_reason</code> column for the conflict
 156        reason. Always <code class="literal">NULL</code> for physical slots.
 157       </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
 158        <code class="structfield">invalidation_reason</code> <code class="type">text</code>
 159       </p>
 160       <p>
 161        The reason for the slot's invalidation. It is set for both logical and
 162        physical slots. <code class="literal">NULL</code> if the slot is not invalidated.
 163        Possible values are:
 164        </p><div class="itemizedlist"><ul class="itemizedlist compact" style="list-style-type: disc; "><li class="listitem"><p>
 165           <code class="literal">wal_removed</code> means that the required WAL has been
 166           removed.
 167          </p></li><li class="listitem"><p>
 168           <code class="literal">rows_removed</code> means that the required rows have
 169           been removed. It is set only for logical slots.
 170          </p></li><li class="listitem"><p>
 171           <code class="literal">wal_level_insufficient</code> means that the
 172           primary doesn't have a <a class="xref" href="runtime-config-wal.html#GUC-WAL-LEVEL">wal_level</a> sufficient to
 173           perform logical decoding.  It is set only for logical slots.
 174          </p></li><li class="listitem"><p>
 175           <code class="literal">idle_timeout</code> means that the slot has remained
 176           inactive longer than the configured
 177           <a class="xref" href="runtime-config-replication.html#GUC-IDLE-REPLICATION-SLOT-TIMEOUT">idle_replication_slot_timeout</a> duration.
 178          </p></li></ul></div><p>
 179       </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
 180        <code class="structfield">failover</code> <code class="type">bool</code>
 181       </p>
 182       <p>
 183        True if this is a logical slot enabled to be synced to the standbys
 184        so that logical replication can be resumed from the new primary
 185        after failover. Always false for physical slots.
 186       </p></td></tr><tr><td class="catalog_table_entry"><p class="column_definition">
 187        <code class="structfield">synced</code> <code class="type">bool</code>
 188       </p>
 189       <p>
 190        True if this is a logical slot that was synced from a primary server.
 191        On a hot standby, the slots with the synced column marked as true can
 192        neither be used for logical decoding nor dropped manually. The value
 193        of this column has no meaning on the primary server; the column value on
 194        the primary is default false for all slots but may (if leftover from a
 195        promoted standby) also be true.
 196       </p></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="view-pg-replication-origin-status.html" title="53.19. pg_replication_origin_status">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="views.html" title="Chapter 53. System Views">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="view-pg-roles.html" title="53.21. pg_roles">Next</a></td></tr><tr><td width="40%" align="left" valign="top">53.19. <code class="structname">pg_replication_origin_status</code> </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 18.0 Documentation">Home</a></td><td width="40%" align="right" valign="top"> 53.21. <code class="structname">pg_roles</code></td></tr></table></div></body></html>