| From: | Jim Nasby <Jim(dot)Nasby(at)BlueTreble(dot)com> |
|---|---|
| To: | Pg Hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Improve output of BitmapAnd EXPLAIN ANALYZE |
| Date: | 2016-10-20 20:24:20 |
| Message-ID: | 499ac0ee-e515-5c65-55c2-56cfc204d52e@BlueTreble.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
A customer just pinged me wondering how it was that a BitmapAnd node was
reporting 0 tuples when the Bitmap Heap Scan above it showed it had in
fact generated tuples.
While this is mentioned in the docs, I think it would be very helpful to
have ANALYZE spit out "N/A" instead of 0 for these nodes. AFAICT that
would just require adding a special case to the "if (es->costs)" block
at line ~1204 in explain.c?
BTW, it looks like it would actually be possible to return a real
row-count if none of the TIDBitmap pages are chunks, but I'm not sure if
it's worth the extra effort.
--
Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
Experts in Analytics, Data Architecture and PostgreSQL
Data in Trouble? Get it in Treble! http://BlueTreble.com
855-TREBLE2 (855-873-2532) mobile: 512-569-9461
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Tom Lane | 2016-10-20 20:35:09 | Re: Improve output of BitmapAnd EXPLAIN ANALYZE |
| Previous Message | Alvaro Herrera | 2016-10-20 20:16:04 | Re: emergency outage requiring database restart |