Re: Reducing walreceiver latency with a latch

On 14/09/10 05:02, Fujii Masao wrote:
> + /*
> + * 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?

Yes, good point. I updated the patch along those lines, attached.

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com