Re: patch: fix performance problems with repated decomprimation of varlena values in plpgsql

2011/3/11 Bruce Momjian <bruce(at)momjian(dot)us>:
>
> What happened with this patch?  Alvaro saw a 25x speedup.

There is not conformance about form in this patch. But there are a
FOREACH statement - so if somebody uses this statement, then he will
not have a problems with performance.

Regards

Pavel

>
> ---------------------------------------------------------------------------
>
> Pavel Stehule wrote:
>> Hello
>>
>> this patch remove a multiple detoasting of varlena values in plpgsql.
>>
>> It is usable mainly for iteration over longer array directly loaded
>> from relation.
>>
>> It's doesn't have a impact on semantic or behave - it's just eliminate
>> some performance trap.
>>
>> sample: table 10000 rows one column with array with 1000 string fields:
>>
>> patched pl time: 6 sec
>> unpatched pl time: 170 sec
>>
>> This doesn't change my opinion on FOR-IN-ARRAY cycle (is still
>> important for readability) - just remove one critical performance
>> issue
>>
>> Regards
>>
>> Pavel Stehule
>
> [ Attachment, skipping... ]
>
>>
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> --
>  Bruce Momjian  <bruce(at)momjian(dot)us>        http://momjian.us
>  EnterpriseDB                             http://enterprisedb.com
>
>  + It's impossible for everything to be true. +
>