doc: Fix documenation for snapshot export in logical decoding.

MasaoFujii · MasaoFujii · commit 90558dbf5483 · 2025-05-26T12:49:09.000+09:00
The documentation for exported snapshots in logical decoding previously stated that snapshot creation may fail on a hot standby. This is no longer accurate, as snapshot exporting on standbys has been supported since PostgreSQL 10. This commit removes the outdated description. Additionally, the docs referred to the NOEXPORT_SNAPSHOT option to suppress snapshot exporting in CREATE_REPLICATION_SLOT. However, since PostgreSQL 15, NOEXPORT_SNAPSHOT is considered legacy syntax and retained only for backward compatibility. This commit updates the documentation for v15 and later to use the modern equivalent: SNAPSHOT 'nothing'. The older syntax is preserved in documentation for v14 and earlier. Back-patched to all supported branches. Reported-by: Kevin K Biju <kevinkbiju@gmail.com> Author: Fujii Masao <masao.fujii@gmail.com> Reviewed-by: Kevin K Biju <kevinkbiju@gmail.com> Discussion: https://postgr.es/m/174791480466.798.17122832105389395178@wrigleys.postgresql.org Backpatch-through: 13
diff --git a/doc/src/sgml/logicaldecoding.sgml b/doc/src/sgml/logicaldecoding.sgml
@@ -455,9 +455,8 @@ postgres=# select * from pg_logical_slot_get_changes('regression_slot', NULL, NU
      using the slot's contents without losing any changes.
     </para>
     <para>
-     Creation of a snapshot is not always possible.  In particular, it will
-     fail when connected to a hot standby.  Applications that do not require
-     snapshot export may suppress it with the <literal>NOEXPORT_SNAPSHOT</literal>
+     Applications that do not require
+     snapshot export may suppress it with the <literal>SNAPSHOT 'nothing'</literal>
      option.
     </para>
    </sect2>
