Re: Reducing walreceiver latency with a latch

On Mon, Sep 13, 2010 at 9:13 PM, Heikki Linnakangas
<heikki.linnakangas@enterprisedb.com> wrote:
> Here's an updated patch with those bugs fixed.

Great!

+	/*
+	 * Walreceiver sets this latch every time new WAL has been received and
+	 * fsync'd to disk, allowing startup process to wait for new WAL to
+	 * arrive.
+	 */
+	Latch		receivedLatch;

I think that this latch should be available for other than walreceiver -
startup process communication. For example, backend - startup process
communication, which can be used for requesting a failover via SQL function
by users in the future. What about putting the latch in XLogCtl instead of
WalRcv and calling OwnLatch at the beginning of the startup process instead
of RequestXLogStreaming?

Regards,

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