From: | "Merlin Moncure" <mmoncure(at)gmail(dot)com> |
---|---|
To: | "Andrew Chernow" <ac(at)esilo(dot)com> |
Cc: | "Matthieu Imbert" <matthieu(dot)imbert(at)ens-lyon(dot)fr>, "Jeroen Vermeulen" <jtv(at)xs4all(dot)nl>, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: binary representation of datatypes |
Date: | 2008-10-22 12:18:17 |
Message-ID: | b42b73150810220518vb1f02eeh1f696bf60e35e935@mail.gmail.com |
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On Wed, Oct 22, 2008 at 8:07 AM, Andrew Chernow <ac(at)esilo(dot)com> wrote:
>>> You mean that when results are asked in textual representation (the
>>> default), data is sent on network directly as text?
>>
>> You should know that text/binary conversions rarely play a significant
>> role in terms of performance. There are exceptions...large bytea
>> columns, or enormous sets of integers. This is coming from a guy that
>> co-wrote a library that allows you to pull data directly in binary.
>>
>> merlin
>>
>
> If I remember correctly, composites and composite arrays also show worth
> while performance gains. libpq array and composite handling is what
> initially spawned the libpqtypes project (which required providing type
> handling for every basic type like int and text). So, different types were
> implemented for different reasons, it was not all performance. The ultimate
> functionality we were looking for was multiple result sets, which composite
> arrays solve nicely.
sure. That isn't, strictly speaking, a performance argument...it's
also a convenience thing.
You won't see a difference either way unless the arrays are large, or
a lot of them (big result sets). For smaller result sets, the
overhead of executing the query is where all the time is spent.
merlin
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