On Wed, Feb 17, 2010 at 6:28 AM, Magnus Hagander <mag...@hagander.net> wrote: > If you send me your amazon id, I can get you premissions on my private > image. I plan to clean it up and make it public, just haven't gotten > around to it yet...
Thanks for your concern! I'll send the ID when I complete the preparation. And, fortunately?, when I set wal_sync_method to open_sync, the problem was reproduced in the linux, too. The cause is that the data that is written by walreceiver is not aligned, even if O_DIRECT is used. On win32, O_DIRECT is used by default. So the problem always happened on win32. I propose two solution ideas: 1. O_DIRECT is somewhat harmful in the standby since the data written by walreceiver is read by the startup process immediately. So, how about not making only walreceiver use O_DIRECT? 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. Which is better? Or do you have another better idea? Regards, -- Fujii Masao NIPPON TELEGRAPH AND TELEPHONE CORPORATION NTT Open Source Software Center -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
