Re: 9.4 checksum errors in recovery with gin index

On Wed, May 7, 2014 at 1:40 PM, Heikki Linnakangas
<hlinnakangas(at)vmware(dot)com>wrote:

> On 05/07/2014 10:35 AM, Jeff Janes wrote:
>
>> When recovering from a crash (with injection of a partial page write at
>> time of crash) against 7c7b1f4ae5ea3b1b113682d4d I get a checksum
>> verification failure.
>>
>> 16396 is a gin index.
>>
>> If I have it ignore checksum failures, there is no apparent misbehavior.
>> I'm trying to bisect it, but it could take a while and I thought someone
>> might have some theories based on the log:
>>
>> 29075 2014-05-06 23:29:51.411 PDT:LOG: 00000: database system was not
>> properly shut down; automatic recovery in progress
>> 29075 2014-05-06 23:29:51.411 PDT:LOCATION: StartupXLOG, xlog.c:6361
>> 29075 2014-05-06 23:29:51.412 PDT:LOG: 00000: redo starts at 11/323FE1C0
>> 29075 2014-05-06 23:29:51.412 PDT:LOCATION: StartupXLOG, xlog.c:6600
>> 29075 2014-05-06 23:29:51.471 PDT:WARNING: 01000: page verification
>> failed, calculated checksum 35967 but expected 7881
>> 29075 2014-05-06 23:29:51.471 PDT:CONTEXT: xlog redo Delete list pages
>>
>
> A-ha. The WAL record of list page deletion doesn't create a full-page
> images of the deleted pages. That's pretty sensible, as a deleted page
> doesn't contain any data that needs to be retained. However, if a full-page
> image is not taken, then the page should be completely recreated from
> scratch at replay. It's not doing that.
>
> Thanks for the testing! I'll have a stab at fixing that tomorrow.
> Basically, ginRedoDeleteListPages() needs to re-initialize the deleted
> pages.

It looks like it is solved now.

Thanks,

Jeff