Re: Logical replication very slow

Поиск
Список
Период
Сортировка
От Boris Sagadin
Тема Re: Logical replication very slow
Дата
Msg-id CAEzn=HRORrCev7FnhYK+tqt_H51Y6YBUPLyQ8=c6D9aC2Ga59Q@mail.gmail.com
обсуждение исходный текст
Ответ на Re: Logical replication very slow  (Achilleas Mantzios <achill@matrix.gatewaynet.com>)
Ответы Re: Logical replication very slow  (Achilleas Mantzios <achill@matrix.gatewaynet.com>)
Список pgsql-general
Дерево обсуждения

Doing an initial replica.

postgres 119454 93.5 25.9 34613692 32649656 ?   Rs   07:16  32:45  \_ postgres: 10/main: bgworker: logical replication worker for subscription 24783 sync 16500

I've cancelled the sync, set the tables to unlogged type and started it again. I think it helped, still much slower than binary, but better, about 40MB/s. Will set them back to logged type after initial replica is done.

After the initial replica, there aren't that many updates, so it's OK then. But if a need for a new slave arises, waiting a few days for initial replica to finish, which in binary replication case is just hours, can be a big problem for us.

Boris


On Mon, Feb 25, 2019 at 8:08 AM Achilleas Mantzios <achill@matrix.gatewaynet.com> wrote:
On 25/2/19 8:52 π.μ., Boris Sagadin wrote:
Doing an initial replica and trying to find a bottleneck, Ubuntu 16.04, NVMe disks, PgSQL v10.7, AWS. With binary replication, DB is replicated at good speed, around 500MB/s. Trying LR now for a big table (about 1.4TB with 2 indexes) and the speed is only about 2MB/s.

Is logical replication subscriber in "streaming" state or in initial snapshot? What's the behavior after the initial snapshot, when it gets into streaming state?
Checked disk util with iostat and only about 20% utilized on master, 15% on target, CPU load on master is low. On slave I can see the "logical replication worker" process is taking about 70% CPU time on a single core, machine has 16 cores.

Is there a setting I am missing here? Any ideas appreciated.

Boris





-- 
Achilleas Mantzios
IT DEV Lead
IT DEPT
Dynacom Tankers Mgmt

В списке pgsql-general по дате отправления:

Предыдущее
От: Mike Yeap
Дата:
Сообщение: Re: LDAP authenticated session terminated by signal 11: Segmentationfault, PostgresSQL server terminates other active server processes
Следующее
От: Thomas Munro
Дата:
Сообщение: Re: LDAP authenticated session terminated by signal 11: Segmentationfault, PostgresSQL server terminates other active server processes