Re: WAL consistency check facility

On Wed, Dec 21, 2016 at 10:53 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> On Mon, Nov 28, 2016 at 11:31 PM, Michael Paquier
> <michael(dot)paquier(at)gmail(dot)com> wrote:
>> Moved to CF 2017-01, as no committers have showed up yet :(
>
> Seeing no other volunteers, here I am.
>
Thanks Robert for looking into the patch.

> On a first read-through of this patch -- I have not studied it in
> detail yet -- this looks pretty good to me. One concern is that this
> patch adds a bit of code to XLogInsert(), which is a very hot piece of
> code. Conceivably, that might produce a regression even when this is
> disabled; if so, we'd probably need to make it a build-time option. I
> hope that's not necessary, because I think it would be great to
> compile this into the server by default, but we better make sure it's
> not a problem. A bulk load into an existing table might be a good
> test case.
>
I'll do this test and post the results.

> + if (!XLogRecGetBlockTag(record, block_id, &rnode, &forknum, &blkno))
> + {
> + /* Caller specified a bogus block_id. Do nothing. */
> + continue;
> + }
>
> Why would the caller do something so dastardly?
>
Sorry, it's my bad. I've copied the code from somewhere else, but forgot
to modify the comment. It should be something like
/* block_id is not used. */

I'll modify the above along with other suggested changes.

--
Thanks & Regards,
Kuntal Ghosh
EnterpriseDB: http://www.enterprisedb.com