Re: WALWriter active during recovery

On 2 July 2015 at 14:31, Fujii Masao <masao(dot)fujii(at)gmail(dot)com> wrote:

> On Thu, Mar 5, 2015 at 5:22 PM, Fujii Masao <masao(dot)fujii(at)gmail(dot)com> wrote:
> > On Thu, Dec 18, 2014 at 6:43 PM, Fujii Masao <masao(dot)fujii(at)gmail(dot)com>
> wrote:
> >> On Tue, Dec 16, 2014 at 3:51 AM, Simon Riggs <simon(at)2ndquadrant(dot)com>
> wrote:
> >>> Currently, WALReceiver writes and fsyncs data it receives. Clearly,
> >>> while we are waiting for an fsync we aren't doing any other useful
> >>> work.
> >>>
> >>> Following patch starts WALWriter during recovery and makes it
> >>> responsible for fsyncing data, allowing WALReceiver to progress other
> >>> useful actions.
> >
> > With the patch, replication didn't work fine in my machine. I started
> > the standby server after removing all the WAL files from the standby.
> > ISTM that the patch doesn't handle that case. That is, in that case,
> > the standby tries to start up walreceiver and replication to retrieve
> > the REDO-starting checkpoint record *before* starting up walwriter
> > (IOW, before reaching the consistent point). Then since walreceiver works
> > without walwriter, no received WAL data cannot be fsync'd in the standby.
> > So replication cannot advance furthermore. I think that walwriter needs
> > to start before walreceiver starts.
> >
> > I just marked this patch as Waiting on Author.
>
> This patch was moved to current CF with the status "Needs review".
> But there are already some review comments which have not been addressed
> yet,
> so I marked the patch as "Waiting on Author" again.
>

This was pushed back from last CF and I haven't worked on it at all, nor
will I.

Pushing back again.

--
Simon Riggs http://www.2ndQuadrant.com/
<http://www.2ndquadrant.com/>
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