system. Monitoring systems should choose whether to represent this
    as missing data, zero or continue to display the last known value.
   </para>
  </note>

 </sect2>

 <sect2 id="monitoring-pg-stat-replication-slots-view">
  <title><structname>pg_stat_replication_slots</structname></title>

  <indexterm>
   <primary>pg_stat_replication_slots</primary>
  </indexterm>

  <para>
   The <structname>pg_stat_replication_slots</structname> view will contain
   one row per logical replication slot, showing statistics about its usage.
  </para>

  <table id="pg-stat-replication-slots-view" xreflabel="pg_stat_replication_slots">
   <title><structname>pg_stat_replication_slots</structname> View</title>
   <tgroup cols="1">
    <thead>
     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
        Column Type
       </para>
       <para>
        Description
      </para></entry>
     </row>
    </thead>

    <tbody>
     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
        <structfield>slot_name</structfield> <type>text</type>
       </para>
       <para>
        A unique, cluster-wide identifier for the replication slot
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
        <structfield>spill_txns</structfield> <type>bigint</type>
       </para>
       <para>
        Number of transactions spilled to disk once the memory used by
        logical decoding to decode changes from WAL has exceeded
        <literal>logical_decoding_work_mem</literal>. The counter gets
        incremented for both top-level transactions and subtransactions.
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
        <structfield>spill_count</structfield> <type>bigint</type>
       </para>
       <para>
        Number of times transactions were spilled to disk while decoding
        changes from WAL for this slot. This counter is incremented each time
        a transaction is spilled, and the same transaction may be spilled
        multiple times.
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
        <structfield>spill_bytes</structfield> <type>bigint</type>
       </para>
       <para>
        Amount of decoded transaction data spilled to disk while performing
        decoding of changes from WAL for this slot. This and other spill
        counters can be used to gauge the I/O which occurred during logical
        decoding and allow tuning <literal>logical_decoding_work_mem</literal>.
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
        <structfield>stream_txns</structfield> <type>bigint</type>
       </para>
       <para>
        Number of in-progress transactions streamed to the decoding output
        plugin after the memory used by logical decoding to decode changes
        from WAL for this slot has exceeded
        <literal>logical_decoding_work_mem</literal>. Streaming only
        works with top-level transactions (subtransactions can't be streamed
        independently), so the counter is not incremented for subtransactions.
       </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
        <structfield>stream_count</structfield><type>bigint</type>
       </para>
       <para>
        Number of times in-progress transactions were streamed to the decoding
        output plugin while decoding changes from WAL for this slot. This
        counter is incremented each time a transaction is streamed, and the
        same transaction may be streamed multiple times.
      </para></entry>
     </row>

     <row>
      <entry role="catalog_table_entry"><para role="column_definition">
        <structfield>stream_bytes</structfield><type>bigint</type>
       </para>