On Thu, Jul 14, 2011 at 9:57 AM, Fujii Masao <masao.fu...@gmail.com> wrote:
> Currently walwriter might write out the WAL before a transaction commits. > IOW, walwriter tries to write out the WAL in wal_buffers in every wakeups. > This might be useful for long transaction which generates lots of WAL > records before commit. So we should call SetLatch() in XLogInsert() instead > of RecordTransactionCommit()? Though I'm not sure how much walwriter > improves the performance of synchronous commit case.. Yeh, we did previously have a heuristic to write out the WAL when it was more than half full. Not sure I want to put exactly that code back into such a busy code path. I suggest that we set latch every time the wal buffers wrap. So at the bottom of AdvanceXLInsertBuffer(), if nextidx == 0 then SetLatch on the WALWriter. That's a simple test and we only check it if we're switch WAL buffer page. -- Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
