doc: Clarify old WAL files are kept until they are summarized.

MasaoFujii · MasaoFujii · commit 56499315a74f · 2024-12-15T11:18:18.000+09:00
The documentation in wal.sgml explains that old WAL files cannot be removed or recycled until they are archived (when WAL archiving is used) or replicated (when using replication slots). However, it did not mention that, similarly, old WAL files are also kept until they are summarized if WAL summarization is enabled. This commit adds that clarification to the documentation. Back-patch to v17 where WAL summarization was added. Author: Fujii Masao Reviewed-by: Michael Paquier Discussion: https://postgr.es/m/fd0eb0a5-f43b-4e06-b450-cbca011b6cff@oss.nttdata.com
diff --git a/doc/src/sgml/wal.sgml b/doc/src/sgml/wal.sgml
@@ -643,6 +643,9 @@
    until the situation is resolved. A slow or failed standby server that
    uses a replication slot will have the same effect (see
    <xref linkend="streaming-replication-slots"/>).
+   Similarly, if <link linkend="runtime-config-wal-summarization">
+   WAL summarization</link> is enabled, old segments are kept
+   until they are summarized.
   </para>
 
   <para>
