Re: when the IndexScan reset to the next ScanKey for in operator

Hi,

At Wed, 21 Aug 2019 20:58:47 +0800, Alex <zhihui(dot)fan1213(at)gmail(dot)com> wrote in <CAKU4AWoUnnZE5oz71+pPu=xSHQBeDM649NKMuOxfhATWAzx22g(at)mail(dot)gmail(dot)com>
> postgres=# select * from t2 where a in (1, 100000);
...
> I can see the plan stores the "1 and 100000" information in
> IndexScan->indexqual, which is an SCALARARRAYOPEXPR expression.
...
> suppose the executor should scan 1 first, If all the tuples for 1 has
> been scanned, then **it should be reset to 100000** and scan again.
> however I can't find out the code for that. looks index_rescan is not for
> this. am I miss something?

Perhaps _bt_advance_array_keys() and btgettuple() would be what
you are seeking for.

> /* ... otherwise see if we have more array keys to deal with */
> } while (so->numArrayKeys && _bt_advance_array_keys(scan, dir));

regards.

--
Kyotaro Horiguchi
NTT Open Source Software Center