Re: -EXT-Re: Table not using tsvector gin index and performance much worse than when it uses it.

From my experience, you want to really tighten the autovacuum_analyze parameters.

I recommend our users to use:

autovacuum_analyze_threshold = 1

autovacuum_analyze_scale_factor = 0.0

Analyze is quite cheap, and the speed difference between an optimal and a suboptimal plans are usually pretty big.

My 2c,

Igor

-----Original Message-----
From: pgsql-performance-owner(at)postgresql(dot)org [mailto:pgsql-performance-owner(at)postgresql(dot)org] On Behalf Of rverghese
Sent: Wednesday, April 05, 2017 4:54 PM
To: pgsql-performance(at)postgresql(dot)org
Subject: -EXT-[PERFORM] Re: Table not using tsvector gin index and performance much worse than when it uses it.

Thanks for the response!

* We are on version 9.5.6

* Less than 10% of the table was updated today (between the time of the last reindex to when performance deteriorated)

* autovacuum is on. I don't see an autoanalyze property in config but these are the settings for analyze

/autovacuum_analyze_threshold = 3000 # min number of row updates before

analyze

#autovacuum_vacuum_scale_factor = 0.2 # fraction of table size before

vacuum

#autovacuum_analyze_scale_factor = 0.1 # fraction of table size before analyze #autovacuum_freeze_max_age = 200000000 # maximum XID age before forced vacuum

# (change requires restart)/

* And this #gin_pending_list_limit = 4MB

* gin_clean_pending_list() is not available.

Will play with gin_pending_list_limit and see what that does.

Thanks!

RV

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