"Tom Lane" <tgl@sss.pgh.pa.us> wrote
>
> Really? An indexscan will release pin before returning no-more-tuples,
> and had better do so else we leak pins during queries involving many
> indexscans.
>
I guess I see your point. For the scan stages not returning no-more-tuples,
we can do kill, but the problem is that most bitmap index scan can finish in
just one round :-(.
>
> Not sure I believe that either. Even granting the assumption that the
> pages are still in cache, this implies a big increase in bufmgr traffic.
>
If you mean the bufmgr traffic is on the BufMappingLock, then I don't worry
too much. Notice that we can have a list of buffer_ids that we are
interested in, we can pin/recheck-buftag of these targets without asking
bufmgr where are they. If we missed, then unpin and forget them is ok.
Regards,
Qingqing
