Rename wal_keep_segments to wal_keep_size.

max_slot_wal_keep_size that was added in v13 and wal_keep_segments are
the GUC parameters to specify how much WAL files to retain for
the standby servers. While max_slot_wal_keep_size accepts the number of
bytes of WAL files, wal_keep_segments accepts the number of WAL files.
This difference of setting units between those similar parameters could
be confusing to users.

To alleviate this situation, this commit renames wal_keep_segments to
wal_keep_size, and make users specify the WAL size in it instead of
the number of WAL files.

There was also the idea to rename max_slot_wal_keep_size to
max_slot_wal_keep_segments, in the discussion. But we have been moving
away from measuring in segments, for example, checkpoint_segments was
replaced by max_wal_size. So we concluded to rename wal_keep_segments
to wal_keep_size.

Back-patch to v13 where max_slot_wal_keep_size was added.

Author: Fujii Masao
Reviewed-by: Álvaro Herrera, Kyotaro Horiguchi, David Steele
Discussion: https://postgr.es/m/574b4ea3-e0f9-b175-ead2-ebea7faea855@oss.nttdata.com

1 files changed, 5 insertions, 5 deletions

diff --git a/src/test/recovery/t/019_replslot_limit.pl b/src/test/recovery/t/019_replslot_limit.pl
index 1fced12fca5..20f4a1bbc3d 100644
--- a/src/test/recovery/t/019_replslot_limit.pl
+++ b/src/test/recovery/t/019_replslot_limit.pl
@@ -116,19 +116,19 @@ $start_lsn = $node_primary->lsn('write');
 $node_primary->wait_for_catchup($node_standby, 'replay', $start_lsn);
 $node_standby->stop;
 
-# wal_keep_segments overrides max_slot_wal_keep_size
+# wal_keep_size overrides max_slot_wal_keep_size
 $result = $node_primary->safe_psql('postgres',
-	"ALTER SYSTEM SET wal_keep_segments to 8; SELECT pg_reload_conf();");
+	"ALTER SYSTEM SET wal_keep_size to '8MB'; SELECT pg_reload_conf();");
 # Advance WAL again then checkpoint, reducing remain by 6 MB.
 advance_wal($node_primary, 6);
 $result = $node_primary->safe_psql('postgres',
 	"SELECT wal_status as remain FROM pg_replication_slots WHERE slot_name = 'rep1'"
 );
 is($result, "extended",
-	'check that wal_keep_segments overrides max_slot_wal_keep_size');
-# restore wal_keep_segments
+	'check that wal_keep_size overrides max_slot_wal_keep_size');
+# restore wal_keep_size
 $result = $node_primary->safe_psql('postgres',
-	"ALTER SYSTEM SET wal_keep_segments to 0; SELECT pg_reload_conf();");
+	"ALTER SYSTEM SET wal_keep_size to 0; SELECT pg_reload_conf();");
 
 # The standby can reconnect to primary
 $node_standby->start;