Re: "failed to find parent tuple for heap-only tuple" error as an ERRCODE_DATA_CORRUPTION ereport()

On Thu, Mar 1, 2018 at 11:15 AM, David Steele <david(at)pgmasters(dot)net> wrote:
> On 12/15/17 5:31 PM, Peter Geoghegan wrote:
>> Commit d70cf811, from 2014, promoted an Assert() within
>> IndexBuildHeapScan() to a "can't happen" elog() error, in order to
>> detect when a parent tuple cannot be found for some heap-only tuple --
>> if this happens, then it indicates corruption. I think that we should
>> make it a full ereport(), with an errcode of ERRCODE_DATA_CORRUPTION,
>> to match what Andres just added to code that deals with freezing (he
>> promoted Assert()s to errors, just like the 2014 commit, though he
>> went as far as making them ereport()s to begin with). Attached patch
>> does this.
>>
>> I propose a backpatch to 9.3, partially for the sake of tools like
>> amcheck, where users may only be on the lookout for
>> ERRCODE_DATA_CORRUPTION and ERRCODE_INDEX_CORRUPTED.
>
> This patch applies, passes testing, and appears very straight-forward to
> me. Are there any tests for these conditions currently, or are you only
> doing that in amcheck?

The enhanced amcheck in the current CF only tests these conditions
indirectly, by pretending to be a CREATE INDEX statement. It matters
to amcheck because these conditions are pretty plausible symptoms of
corruption, and I can imagine someone missing them because they are
not either ERRCODE_DATA_CORRUPTION or ERRCODE_INDEX_CORRUPTED.

If amcheck didn't exist, then I'd still think that this patch was worthwhile.

--
Peter Geoghegan