RE: Allowing WAL fsync to be done via O_SYNC - Mailing list pgsql-hackers

From Mikheev, Vadim
Subject RE: Allowing WAL fsync to be done via O_SYNC
Date
Msg-id 8F4C99C66D04D4118F580090272A7A234D3323@sectorbase1.sectorbase.com
Whole thread Raw
In response to Allowing WAL fsync to be done via O_SYNC  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Allowing WAL fsync to be done via O_SYNC
List pgsql-hackers
> > I was wondering if the multiple writes performed to the 
> > XLOG could be grouped into one write().
> 
> That would require fairly major restructuring of xlog.c, which I don't

Restructing? Why? It's only XLogWrite() who make writes.

> want to undertake at this point in the cycle (we're trying to push out
> a release candidate, remember?).  I'm not convinced it would be a huge
> win anyway.  It would be a win if your average transaction writes
> multiple blocks' worth of XLOG ... but if your average transaction
> writes less than a block then it won't help.

But in multi-user environment multiple transactions may write > 1 block
before commit.

> I think it probably is a good idea to restructure xlog.c so 
> that it can write more than one page at a time --- but it's
> not such a great idea that I want to hold up the release any
> more for it.

Agreed.

Vadim


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