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-rw-r--r--doc/src/sgml/ref/pgupgrade.sgml12
1 files changed, 7 insertions, 5 deletions
diff --git a/doc/src/sgml/ref/pgupgrade.sgml b/doc/src/sgml/ref/pgupgrade.sgml
index df13365b287..648c6e2967c 100644
--- a/doc/src/sgml/ref/pgupgrade.sgml
+++ b/doc/src/sgml/ref/pgupgrade.sgml
@@ -833,17 +833,19 @@ psql --username=postgres --file=script.sql postgres
<para>
Because not all statistics are not transferred by
- <command>pg_upgrade</command>, you will be instructed to run a command to
+ <command>pg_upgrade</command>, you will be instructed to run commands to
regenerate that information at the end of the upgrade. You might need to
set connection parameters to match your new cluster.
</para>
<para>
- Using <command>vacuumdb --all --analyze-only --missing-stats-only</command>
- can efficiently generate such statistics. Alternatively,
+ First, use
<command>vacuumdb --all --analyze-in-stages --missing-stats-only</command>
- can be used to generate minimal statistics quickly. For either command,
- the use of <option>--jobs</option> can speed it up.
+ to quickly generate minimal optimizer statistics for relations without
+ any. Then, use <command>vacuumdb --all --analyze-only</command> to ensure
+ all relations have updated cumulative statistics for triggering vacuum and
+ analyze. For both commands, the use of <option>--jobs</option> can speed
+ it up.
If <varname>vacuum_cost_delay</varname> is set to a non-zero
value, this can be overridden to speed up statistics generation
using <envar>PGOPTIONS</envar>, e.g., <literal>PGOPTIONS='-c