Re: Hot standby, RestoreBkpBlocks and cleanup locks

Please commit soon....

On Fri, 2009-01-09 at 18:30 +0200, Heikki Linnakangas wrote:
> The hot standby patch has some hacks to decide which full-page-images
> can be restored holding an exclusive lock and which ones need a
> vacuum-strength lock. It's not very pretty as is, as mentioned in
> comments too.
>
> How about we refactor things so that redo-functions are responsible for
> calling RestoreBkpBlocks? The redo function can then pass an argument
> indicating what kind of lock is required. We should also change
> XLogReadBufferExtended so that it doesn't lock the page; the caller
> knows better what kind of a lock it needs. That makes it more analogous
> with ReadBufferExtended too, although I think we should keep
> XLogReadBuffer() unchanged for now.
>
> See attached patch. One shortfall of this patch is that you can pass
> only one argument to RestoreBkpBlocks, but there can multiple backup
> blocks in one WAL record. That's OK in current usage, though.
>
--
Simon Riggs www.2ndQuadrant.com
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