On 03/09/2024 10:34, Pavel Luzanov wrote:
On 03.09.2024 00:11, Heikki Linnakangas wrote:
Pavel, did you test v17 with checksums enabled and v16 with checksums
disabled, by any chance?
Exactly, You are right!
My v16 cluster comes from the default Ubuntu distribution.
I forgot that checksums disabled by default.
But when I initialize the master cluster, I automatically set -k option.
More accurate results for the test:
CREATE TABLE t(id integer) WITH (autovacuum_enabled = off);
INSERT INTO t SELECT gen.id FROM generate_series(1,3_500_000) gen(id);
VACUUM FREEZE t;
UPDATE t SET id = id + 1;
VACUUM FREEZE VERBOSE t;
checksums disabled
v16.4 WAL usage: 77437 records, 20832 full page images, 110654467 bytes
master WAL usage: 61949 records, 20581 full page images, 92549229 bytes
checksums enabled
v16.4 WAL usage: 92848 records, 20985 full page images, 194863720 bytes
master WAL usage: 76520 records, 20358 full page images, 181867154 bytes
That's more like it :-)
This a great optimization!
Peter, Melanie, Heikki,
Thank you very much for your help and time spent!
Sorry for the noise before the release of PG17.
Thanks for the testing!
--
Heikki Linnakangas
Neon (https://neon.tech)
