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explain analyze select * from objects_hier where tg
&& array[0] and id <10000; Bitmap Heap Scan on objects_hier
(cost=4.79..8.80 rows=1 width=337) (actual time=0.110..0.110 rows=0 loops=1) Recheck Cond: ((tg &&
'{0}'::integer[]) AND (id < 10000)) -> BitmapAnd
(cost=4.79..4.79 rows=1 width=0) (actual time=0.106..0.106 rows=0 loops=1)
-> Bitmap Index Scan on gistbla2 (cost=0.00..2.10 rows=30
width=0) (actual time=0.042..0.042 rows=0 loops=1)
Index Cond: (tg && '{0}'::integer[])
-> Bitmap Index Scan on ohid (cost=0.00..2.44 rows=1240 width=0)
(actual time=0.058..0.058 rows=1255 loops=1)
Index Cond: (id < 10000) I see, Bitmap is going to AND my indexes.. It read
one with less number of rows estimated the first (right).. It found 0 records at gistbla2 index… Then why is it reading ohid ? Maybe a quickfix is possible for cases when 0 records
is found to stop reading other AND elements.. |
- [PERFORM] Bitmap scan when it is not needed Ilia Kantor
