Re: Query planner wants to use seq scan

So,

Tonight, the index on the three field is used, may be my yesterday vacuum updated stats.

Thx you for your help.

Regards,

Bertrand

2015-10-27 18:33 GMT+01:00 Bertrand Paquet <bertrand.paquet@doctolib.fr>:

Hi tom,

I did the test yesterday with an index on the three fields, and with a partial index on organization and status and where is null condition on handled. I saw no modification on query plan.

May be I forgot to analyze vacuum after. I will retry tonight. 

I use a btree index. Is it the good solution, even with the In clause ?

Regards,

Bertrand

Le mardi 27 octobre 2015, Tom Lane <tgl@sss.pgh.pa.us> a écrit :

Bertrand Paquet <bertrand.paquet@doctolib.fr> writes:
> We have a slow query. After analyzing, the planner decision seems to be
> discutable : the query is faster when disabling seqscan. See below the two
> query plan, and an extract from pg_stats.

> Any idea about what to change to help the planner ?

Neither one of those plans is very good: you're just hoping that the
Filter condition will let a tuple through sooner rather than later.

If you care about the performance of this type of query, I'd consider
creating an index on (organization_id, status, handled_by) so that all
the conditions can be checked in the index.

                        regards, tom lane

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