On Wed, Feb 17, 2010 at 3:27 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Magnus Hagander <magnus(at)hagander(dot)net> writes:
>> On Wed, Feb 17, 2010 at 06:55, Fujii Masao <masao(dot)fujii(at)gmail(dot)com> wrote:
>>> 2. Straightforwardly observe the alignment rule. Since the received WAL
>>>   data might start at the middle of WAL block, walreceiver needs to keep
>>>   the last half-written WAL block for alignment. OTOH since the received
>>>   data might end at the middle of WAL block, walreceiver needs zero-padding.
>>>   As a result, walreceiver writes the set of the last WAL block, received
>>>   data and zero-padding.
>
>> May there be other reasons to d this as well?
>
> Writing misaligned data is certain to be expensive even when it works...

Yeah, right. After I remove O_DIRECT, I'll change walreceiver so as to
do an alignment correctly, and then I'll test the performance.

Regards,

-- 
Fujii Masao
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center

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• Re: Streaming replication on win32, still broken at 2010-02-17 06:27:17 from Tom Lane

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