docs: re-add instructions on setting wal_level for rsync use

This step was erroneously removed four days ago by me.

Reported-by: Magnus via IM
Backpatch-through: 9.5

diff --git a/doc/src/sgml/ref/pgupgrade.sgml b/doc/src/sgml/ref/pgupgrade.sgml
index 4e248eae38d5ed07a22cad97c784eda0653b436f..6d5b76abd9b0f6e6875eccc83936a929fbb4fc6b 100644 (file)
--- a/doc/src/sgml/ref/pgupgrade.sgml
+++ b/doc/src/sgml/ref/pgupgrade.sgml
@@ -326,7 +326,9 @@ NET STOP postgresql-9.0
      against the old primary and standby clusters.  Verify that the
      <quote>Latest checkpoint location</> values match in all clusters.
      (There will be a mismatch if old standby servers were shut down
-     before the old primary.)
+     before the old primary.)  Also, change <varname>wal_level</> to
+     <literal>replica</> in the <filename>postgresql.conf</> file on the
+     new primary cluster.
     </para>
    </step>