Am 28.03.19 um 09:33 schrieb Sameer Kumar:
>
> test=*# select * from emp where ename = 'aaa';
> eid | ename
> -----+-------
> 1 | aaa
> 2 | AAA
> (2 rows)
>
>
>
> Ummm... Will it use an index (a BTree index)?
>
test=# explain select * from emp where ename = 'aaa';
QUERY PLAN
-----------------------------------------------------
Seq Scan on emp (cost=0.00..25.88 rows=6 width=36)
Filter: (ename = 'aaa'::citext)
(2 rows)
test=*# set enable_seqscan to off;
SET
test=*# explain select * from emp where ename = 'aaa';
QUERY PLAN
------------------------------------------------------------------------
Seq Scan on emp (cost=10000000000.00..10000000025.88 rows=6 width=36)
Filter: (ename = 'aaa'::citext)
(2 rows)
test=*# create index emp_ename on emp(ename);
CREATE INDEX
test=*# explain select * from emp where ename = 'aaa';
QUERY PLAN
----------------------------------------------------------------------
Index Scan using emp_ename on emp (cost=0.13..8.14 rows=1 width=36)
Index Cond: (ename = 'aaa'::citext)
(2 rows)
test=*#
Regards, Andreas
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