Re: WAL consistency check facility

On Wed, Sep 7, 2016 at 3:52 PM, Kuntal Ghosh <kuntalghosh(dot)2007(at)gmail(dot)com> wrote:
>
> I got two types of inconsistencies as following:
>
> 1. For Btree/UNLINK_PAGE_META, btpo_flags are different. In backup
> page, BTP_DELETED and BTP_LEAF both the flags are set, whereas after
> redo, only BTP_DELETED flag is set in buffer page.
>

I see that inconsistency in code as well. I think this is harmless,
because after the page is marked as deleted, it is not used for any
purpose other than to recycle it for re-use. After re-using it, the
caller always suppose to initialize the flags based on it's usage and
I see that is happening in the code unless I am missing something.

> I assume that we
> should clear all btpo_flags before setting BTP_DELETED in
> _bt_unlink_halfdead_page().
>

Yeah, we can do that for consistency. If we see any problem in doing
so, then I think we can log the flags and set them during replay.

Note - Please post your replies inline rather than top posting them.
It breaks the discussion link, if you top post it.

--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com