| From: | Craig Ringer <craig(at)postnewspapers(dot)com(dot)au> |
|---|---|
| To: | Oliver Jowett <oliver(at)opencloud(dot)com> |
| Cc: | Andreas Schmitz <schmitz(at)occamlabs(dot)de>, pgsql-jdbc(at)postgresql(dot)org |
| Subject: | Re: bytea performance tweak |
| Date: | 2011-06-22 03:27:14 |
| Message-ID: | 4E016112.3080709@postnewspapers.com.au |
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| Thread: | |
| Lists: | pgsql-jdbc |
On 22/06/11 07:59, Oliver Jowett wrote:
> On 22 June 2011 01:08, Andreas Schmitz <schmitz(at)occamlabs(dot)de> wrote:
>> Hi,
>>
>> I've noticed that fetching a bytea field produces a lot of overhead when
>> converting into a byte[] or InputStream. Looking at the code, I've
>> produced a small patch (a lookup table for the hex codes) which makes
>> the conversion faster. What do you think?
>
> Surprising.
It's not at _all_ surprising that an array index lookup is much faster
than two function calls and a bunch of branches. It'll probably JIT
better and be easier on cache, too.
If Oliver is lobbing around mostly bytea data and/or using big bytea
fields I'm not surprised he's seeing this as at least somewhat of a
hotspot. I've seen comments on bytea performance with JDBC here before,
though nobody seems to have dug into it enough to track things down before.
Thanks Oliver!
--
Craig Ringer
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