doc: Improve description of wal_compression

michaelpq · michaelpq · commit b5d87a823f2f · 2025-08-21T13:25:03.000+09:00
The description of this GUC provides a list of the situations where full-page writes are generated. However, it is not completely exact, mentioning only the cases where full_page_writes=on or base backups. It is possible to generate full-page writes in more situations than these two, making the description confusing as it implies that no other cases exist. The description is slightly reworded to take into account that other cases are possible, without mentioning them directly to minimize the maintenance burden should FPWs be generated in more contexts in the future. Author: Jingtang Zhang <mrdrivingduck@gmail.com> Reviewed-by: Andrey Borodin <x4mmm@yandex-team.ru> Reviewed-by: Xuneng Zhou <xunengzhou@gmail.com> Discussion: https://postgr.es/m/CAPsk3_CtAYa_fy4p6=x7qtoutrdKvg1kGk46D5fsE=sMt2546g@mail.gmail.com Backpatch-through: 13
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
@@ -3399,8 +3399,9 @@ include_dir 'conf.d'
         This parameter enables compression of WAL using the specified
         compression method.
         When enabled, the <productname>PostgreSQL</productname>
-        server compresses full page images written to WAL when
-        <xref linkend="guc-full-page-writes"/> is on or during a base backup.
+        server compresses full page images written to WAL (e.g. when
+        <xref linkend="guc-full-page-writes"/> is on, during a base backup,
+        etc.).
         A compressed page image will be decompressed during WAL replay.
         The supported methods are <literal>pglz</literal>,
         <literal>lz4</literal> (if <productname>PostgreSQL</productname>
