| From: | David Fetter <david(at)fetter(dot)org> |
|---|---|
| To: | fazool mein <fazoolmein(at)gmail(dot)com> |
| Cc: | pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: xlog.c: WALInsertLock vs. WALWriteLock |
| Date: | 2010-10-23 20:17:43 |
| Message-ID: | 20101023201743.GB20820@fetter.org |
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| Thread: | |
| Lists: | pgsql-hackers |
On Fri, Oct 22, 2010 at 12:08:54PM -0700, fazool mein wrote:
> Hello guys,
>
> I'm writing a function that will read data from the buffer in xlog
> (i.e. from XLogCtl->pages and XLogCtl->xlblocks). I want to make
> sure that I am doing it correctly.
Got an example of what the function might look like?
> For reading from the buffer, do I need to lock WALInsertLock or
> WALWriteLock? Also, can you explain a bit the usage of 'LW_SHARED'.
> Can we use it for read purposes?
Help me understand. Do you foresee some kind of concurrency issue,
and if so, what?
Cheers,
David.
>
> Thanks a lot.
--
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