Re: fallocate / posix_fallocate for new WAL file creation (etc...) - Mailing list pgsql-hackers

From Peter Eisentraut
Subject Re: fallocate / posix_fallocate for new WAL file creation (etc...)
Date
Msg-id 51A60CE6.9020607@gmx.net
Whole thread Raw
In response to Re: fallocate / posix_fallocate for new WAL file creation (etc...)  (Greg Smith <greg@2ndQuadrant.com>)
Responses Re: fallocate / posix_fallocate for new WAL file creation (etc...)  (Stephen Frost <sfrost@snowman.net>)
List pgsql-hackers
On 5/28/13 11:36 AM, Greg Smith wrote:
> Outside of the run for performance testing, I think it would be good at
> this point to validate that there is really a 16MB file full of zeroes
> resulting from these operations.  I am not really concerned that
> posix_fallocate might be slower in some cases; that seems unlikely.  I
> am concerned that it might result in a file that isn't structurally the
> same as the 16MB of zero writes implementation used now.

I see nothing in the posix_fallocate() man pages that says that the
allocated space is filled with any kind of data or zeroes.  It will
likely be garbage data, but that should be fine for a new WAL file.



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