Re: many sessions waiting DataFileRead and extend
От | Laurenz Albe |
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Тема | Re: many sessions waiting DataFileRead and extend |
Дата | |
Msg-id | 66879d8bd44148f2ef1dcde1eff056e6c671306e.camel@cybertec.at обсуждение исходный текст |
Ответ на | many sessions waiting DataFileRead and extend (James Pang <jamespang886@gmail.com>) |
Ответы |
Re: many sessions waiting DataFileRead and extend
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Список | pgsql-performance |
On Wed, 2025-06-25 at 11:15 +0800, James Pang wrote: > pgv14, RHEL8, xfs , we suddenly see tens of sessions waiting on "DataFileRead" and > "extend", it last about 2 seconds(based on pg_stat_activity query) , during the > waiting time, "%sys" cpu increased to 80% , but from "iostat" , no high iops and > io read/write latency increased either. Run "sar -P all 1" and see if "%iowait" is high. Check if you have transparent hugepages enabled: cat /sys/kernel/mm/transparent_hugepage/enabled If they are enabled, disable them and see if it makes a difference. I am only guessing here. > many sessions were running same "DELETE FROM xxxx" in parallel waiting on "extend" > and "DataFileRead", there are triggers in this table "After delete" to insert/delete > other tables in the tigger. One thing that almost certainly would improve your situation is to run fewer concurrent statements, for example by using a reasonably sized connection pool. Yours, Laurenz Albe
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