Adjust documentation for configuring Linux huge pages.

nathan-bossart · nathan-bossart · commit 053b6daeb9c5 · 2024-10-18T10:20:15.000-05:00
The present wording about viewing shared_memory_size_in_huge_pages seems to suggest that the parameter cannot be viewed after startup at all, whereas the intent is to make it clear that you can't use "postgres -C" to view this parameter while the server is running. This commit rephrases this section to remove the ambiguity. Author: Seino Yuki Reviewed-by: Michael Paquier, David G. Johnston, Fujii Masao Discussion: https://postgr.es/m/420584fd274f9ec4f337da55ffb3b790%40oss.nttdata.com Backpatch-through: 15
diff --git a/doc/src/sgml/runtime.sgml b/doc/src/sgml/runtime.sgml
@@ -1422,11 +1422,10 @@ export PG_OOM_ADJUST_VALUE=0
     with <varname>CONFIG_HUGETLBFS=y</varname> and
     <varname>CONFIG_HUGETLB_PAGE=y</varname>. You will also have to configure
     the operating system to provide enough huge pages of the desired size.
-    To determine the number of huge pages needed, use the
-    <command>postgres</command> command to see the value of
-    <xref linkend="guc-shared-memory-size-in-huge-pages"/>.  Note that the
-    server must be shut down to view this runtime-computed parameter.
-    This might look like:
+    The runtime-computed parameter
+    <xref linkend="guc-shared-memory-size-in-huge-pages"/> reports the number
+    of huge pages required.  This parameter can be viewed before starting the
+    server with a <command>postgres</command> command like:
 <programlisting>
 $ <userinput>postgres -D $PGDATA -C shared_memory_size_in_huge_pages</userinput>
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