Re: Hash Right join and seq scan

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От James Pang
Тема Re: Hash Right join and seq scan
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Msg-id CAHgTRfdpuB36gPAR+oU2-191V92ML-usZZLH7KhRGdanF=simw@mail.gmail.com
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Ответ на Re: Hash Right join and seq scan  (Tomas Vondra <tomas.vondra@enterprisedb.com>)
Ответы Re: Hash Right join and seq scan
Re: Hash Right join and seq scan
Список pgsql-performance
   we have a daily vacuumdb and analyze job, generally speaking it's done in seconds, sometimes it suddenly running more than tens of minutes with same bind variable values and huge temp space got used  and at that time, explain show  "Hash Anti join, Hash Right join" with seq scan two tables.  

Tomas Vondra <tomas.vondra@enterprisedb.com> 於 2024年7月4日週四 上午1:40寫道:
Hi James,

I think it'd be much easier to help you with investigating this issue if
you shared the actual queries, and the full EXPLAIN ANALYZE output both
with and without disabled hashjoin. Or even better, share a script that
reproduces the issue (creates tables, loads data, runs the queries).

BTW you suggested each partition has ~250k rows, but the explain plan
snippet you shared does not seem to be consistent with that - it only
shows 2500-5000 rows per partition. If you run ANALYZE on the table,
does that change the plan?

regards

--
Tomas Vondra
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
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