From: | "Qingqing Zhou" <zhouqq(at)cs(dot)toronto(dot)edu> |
---|---|
To: | pgsql-committers(at)postgresql(dot)org |
Subject: | Re: pgsql: Define a separately configurable XLOG_BLCKSZ symbol for the page |
Date: | 2006-04-04 09:23:05 |
Message-ID: | e0tdtm$l07$1@news.hub.org |
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Lists: | pgsql-committers |
"Tom Lane" <tgl(at)postgresql(dot)org> wrote
> xlog.c (r1.231 -> r1.232)
>
> (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/transam/xlog.c.diff?r1=1.231&r2=1.232)
>
Sorry for my after-fact idea ... I noticed this line in the patch:
@@ -2708,7 +2708,7 @@ ReadRecord(XLogRecPtr *RecPtr, int emode
readId, readSeg, readOff)));
goto next_record_is_invalid;
}
- if (read(readFile, readBuf, BLCKSZ) != BLCKSZ)
+ if (read(readFile, readBuf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
{
ereport(emode,
(errcode_for_file_access(),
This is a patch for write performance, but here theoretically decreases the
read performance due to the possible setting of XLOG_BLCKSZ (say 512 as
sector size, which is << BLCKSZ). It maybe avoidable by still using BLCKSZ
or even more aggresive block size, but may also need some local tweak here.
Regards,
Qingqing
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