Re: Inefficient bytea escaping?
От | Andreas Pflug |
---|---|
Тема | Re: Inefficient bytea escaping? |
Дата | |
Msg-id | 44783D94.7060004@pse-consulting.de обсуждение исходный текст |
Ответ на | Re: Inefficient bytea escaping? (Tom Lane <tgl@sss.pgh.pa.us>) |
Список | pgsql-hackers |
Tom Lane wrote: > I wrote: > >>I'm off for a little visit with oprofile... > > > It seems the answer is that fwrite() does have pretty significant > per-call overhead, at least on Fedora Core 4. The patch I did yesterday > still ended up making an fwrite() call every few characters when dealing > with bytea text output, because it'd effectively do two fwrite()s per > occurrence of '\' in the data being output. I've committed a further > hack that buffers a whole data row before calling fwrite(). Even though > this presumably is adding one extra level of data copying, it seems to > make things noticeably faster: (semi-OT) This recoding seems like a perfect preparation for a third COPY format, compressed. > > Let me know what this does on your Debian machine ... Takes a while, need a different kernel booted because the current isn't oprofile ready. Regards, Andreas
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