Re: Pre-calculate hash join

Dimitri Fontaine skrev 2010-01-12 12.01:
> warren(at)warrenandrachel(dot)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?
>

Depending on your case creating a temporary table in the beginning of
the session might save you a lot of time if multiple similar queries is
done.

Regards,
roppert