From: | Ian Lance Taylor <ian(at)airs(dot)com> |
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To: | "Mikheev, Vadim" <vmikheev(at)SECTORBASE(dot)COM> |
Cc: | pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: WAL does not recover gracefully from out-of-disk-sp ace |
Date: | 2001-03-08 18:51:38 |
Message-ID: | sivgpkf611.fsf@daffy.airs.com |
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"Mikheev, Vadim" <vmikheev(at)SECTORBASE(dot)COM> writes:
> > But we need it regardless --- if you didn't want a fully-allocated WAL
> > file, why'd you bother with the original seek-and-write-1-byte code?
>
> I considered this mostly as hint for OS about how log file should be
> allocated (to decrease fragmentation). Not sure how OSes use such hints
> but seek+write costs nothing.
Doing a seek to a large value and doing a write is not a hint to a
Unix system that you are going to write a large sequential file. If
anything, it's a hint that you are going to write a sparse file. A
Unix kernel will optimize by not allocating blocks you aren't going to
write to.
Ian
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