Logical Replication Message Formats for Transaction and Tuple Data

84th chunk of `doc/src/sgml/protocol.sgml`

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  </listitem>
      </varlistentry>

      <varlistentry>
       <term>Int64 (XLogRecPtr)</term>
       <listitem>
        <para>
         The end LSN of the prepared transaction.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term>Int64 (XLogRecPtr)</term>
       <listitem>
        <para>
         The end LSN of the rollback of the prepared transaction.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term>Int64 (TimestampTz)</term>
       <listitem>
        <para>
         Prepare timestamp of the transaction. The value is in number
         of microseconds since PostgreSQL epoch (2000-01-01).
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term>Int64 (TimestampTz)</term>
       <listitem>
        <para>
         Rollback timestamp of the transaction. The value is in number
         of microseconds since PostgreSQL epoch (2000-01-01).
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term>Int32 (TransactionId)</term>
       <listitem>
        <para>
         Xid of the transaction.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term>String</term>
       <listitem>
        <para>
         The user defined GID of the prepared transaction.
        </para>
       </listitem>
      </varlistentry>
     </variablelist>
    </listitem>
   </varlistentry>

   <varlistentry id="protocol-logicalrep-message-formats-Stream-Prepare">
    <term>Stream Prepare</term>
    <listitem>
     <variablelist>
      <varlistentry>
       <term>Byte1('p')</term>
       <listitem>
        <para>
         Identifies the message as a stream prepared transaction message.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term>Int8(0)</term>
       <listitem>
        <para>
         Flags; currently unused.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term>Int64 (XLogRecPtr)</term>
       <listitem>
        <para>
         The LSN of the prepare.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term>Int64 (XLogRecPtr)</term>
       <listitem>
        <para>
         The end LSN of the prepared transaction.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term>Int64 (TimestampTz)</term>
       <listitem>
        <para>
         Prepare timestamp of the transaction. The value is in number
         of microseconds since PostgreSQL epoch (2000-01-01).
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term>Int32 (TransactionId)</term>
       <listitem>
        <para>
         Xid of the transaction.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term>String</term>
       <listitem>
        <para>
         The user defined GID of the prepared transaction.
        </para>
       </listitem>
      </varlistentry>
     </variablelist>
    </listitem>
   </varlistentry>
  </variablelist>

  <para>
   The following message parts are shared by the above messages.
  </para>

  <variablelist>
   <varlistentry id="protocol-logicalrep-message-formats-TupleData">
    <term>TupleData</term>
    <listitem>
     <variablelist>
      <varlistentry>
       <term>Int16</term>
       <listitem>
        <para>
         Number of columns.
        </para>
       </listitem>
      </varlistentry>
     </variablelist>

     <para>
      Next, one of the following submessages appears for each published column:

      <variablelist>
       <varlistentry>
        <term>Byte1('n')</term>
        <listitem>
         <para>
          Identifies the data as NULL value.
         </para>
        </listitem>
       </varlistentry>
      </variablelist>
      Or
      <variablelist>
       <varlistentry>
        <term>Byte1('u')</term>
        <listitem>
         <para>

Title: Logical Replication Message Formats for Transaction and Tuple Data

Summary

This section describes the message formats for stream prepare, tuple data, and other related messages in logical replication, including details on fields such as LSN, timestamp, transaction ID, and user-defined GID, as well as the structure of tuple data messages, which include information about column numbers and data types, including NULL values.