Re: Opclass parameters of indexes lost after REINDEX CONCURRENTLY

On Sat, Oct 30, 2021 at 1:28 AM Michael Paquier <michael(at)paquier(dot)xyz> wrote:

> Hi all,
>
> While reviewing the code for opclass parameters with indexes, I have
> noticed that opclass parameters are lost after a concurrent reindex.
> As we use a IndexInfo to hold the information of the new index when
> creating a copy of the old one, it is just a matter of making sure
> that ii_OpclassOptions is filled appropriately, but that was missed by
> 911e702.
>
> Attached is a patch to fix the issue. After a concurrent reindex, we
> would not finish with a corrupted index, just with one rebuilt with
> default opclass parameter values.
>
> Any objections or comments?
> --
> Michael
>
Hi,

+ newInfo->ii_OpclassOptions = palloc0(sizeof(Datum) *
+ newInfo->ii_NumIndexAttrs);

It seems we may not need to allocate these many entries (as shown by the
concur_appclass_ind_2 example in the test).
In the previous loop (starting line 1359), we can increment a counter which
would finally tell us how many oldInfo->ii_OpclassOptions[i] is not NULL.

Then that many entries can be allocated in the above code.

Cheers