Re: bad estimation together with large work_mem generates terrible slow hash joins - Mailing list pgsql-hackers

From Tomas Vondra
Subject Re: bad estimation together with large work_mem generates terrible slow hash joins
Date
Msg-id 53CBEE6E.8080702@fuzzy.cz
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In response to Re: bad estimation together with large work_mem generates terrible slow hash joins  (Tomas Vondra <tv@fuzzy.cz>)
Responses Re: bad estimation together with large work_mem generates terrible slow hash joins  (Tomas Vondra <tv@fuzzy.cz>)
List pgsql-hackers
Attached v9 of the patch. Aside from a few minor fixes, the main  change
is that this is assumed to be combined with the "dense allocation" patch.

It also rewrites the ExecHashIncreaseNumBuckets to follow the same
pattern as ExecHashIncreaseNumBatches (i.e. scanning chunks directly,
instead of buckets). It's cleaner and more consistent.

hashjoin-nbuckets-growth-v9.patch contains only this patch, so you need
to grab the hashjoin-alloc-v4.patch from a different thread and apply it
first)

hashjoin-nbuckets-growth-v9-combined.patch contains both patches combined

regards
Tomas Vondra

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