> 28 дек. 2020 г., в 11:14, Andrey Borodin <x4mmm@yandex-team.ru> написал(а):
>
>> Thanks for the patch. Maybe we can allow setting custom compression
>> methods for wal compression as well.
>
> No, unfortunately, we can't use truly custom methods. Custom compression handlers are WAL-logged. So we can use only
staticset of hardcoded compression methods.
So, I've made some very basic benchmarks on my machine [0].
With pglz after checkpoint I observe 1146 and 1225 tps.
With lz4 I observe 1485 and 1524 tps.
Without wal_compression I see 1529 tps.
These observations can be explained with plain statement: pglz is bottleneck on my machine, lz4 is not.
While this effect can be reached with other means [1] I believe having lz4 for WAL FPIs would be much more CPU
efficient.
FPA lz4 for WAL FPI patch v17. Changes: fixed some frontend issues, added some comments.
Best regards, Andrey Borodin.
[0] https://yadi.sk/d/6y5YiROXQRkoEw
[1]
https://www.postgresql.org/message-id/flat/25991595-1848-4178-AA57-872B10309DA2%40yandex-team.ru#e7bb0e048358bcff281011dcf115ad42