Re: Pre-calculate hash join - Mailing list pgsql-general

From Dimitri Fontaine
Subject Re: Pre-calculate hash join
Date
Msg-id 87hbqra8on.fsf@hi-media-techno.com
Whole thread Raw
In response to Pre-calculate hash join  (warren@warrenandrachel.com)
Responses Re: Pre-calculate hash join  (Robert Gravsjö <robert@blogg.se>)
List pgsql-general
warren@warrenandrachel.com writes:

> When joining two large tables [common in warehousing], a hash join is
> commonly selected. Calculating hash values for the merge phase is CPU
> intensive. Is there any way to pre-calculate value hashes to save that
> time? Would it even grant any performance to skip the build phase of
> the hash join?

Maybe maintaining a materialized view then using it in the queries would
be sufficient to solve your problem?

--
dim

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