CIText and pattern_ops
Is there any particular reason why the citext module doesn't have
citext_pattern_ops operator family?
Specifically, I wish to index for this type of query:
... WHERE citext_column LIKE 'Foo%';
This, of course, is equivalent to ILIKE 'Foo%' which does not appear
to be indexable without using a functional index (
lower(citext_column) ).
Rod Taylor <pg@rbt.ca> wrote:
Is there any particular reason why the citext module doesn't have
citext_pattern_ops operator family?Specifically, I wish to index for this type of query:
... WHERE citext_column LIKE 'Foo%';
I think it is a reasonable suggestion.
=# \d tbl
Table "public.tbl"
Column | Type | Modifiers
--------+--------+-----------
t | text |
c | citext |
Indexes:
"tbl_c_idx" btree (c)
"tbl_t_idx" btree (t)
=# SET enable_seqscan = off;
SET
=# EXPLAIN SELECT * FROM tbl WHERE t LIKE 'abc%';
QUERY PLAN
----------------------------------------------------------------------
Index Scan using tbl_t_idx on tbl (cost=0.00..8.27 rows=1 width=64)
Index Cond: ((t >= 'abc'::text) AND (t < 'abd'::text))
Filter: (t ~~ 'abc%'::text)
(3 rows)
=# EXPLAIN SELECT * FROM tbl WHERE c LIKE 'abc%';
QUERY PLAN
------------------------------------------------------------------------
Seq Scan on tbl (cost=10000000000.00..10000000001.01 rows=1 width=64)
Filter: (c ~~ 'abc%'::citext)
(2 rows)
Regards,
---
Takahiro Itagaki
NTT Open Source Software Center
On Fri, Apr 23, 2010 at 11:27 PM, Rod Taylor <pg@rbt.ca> wrote:
Is there any particular reason why the citext module doesn't have
citext_pattern_ops operator family?
You forgot to send in the patch. :-)
...Robert
On 26 April 2010 11:19, Robert Haas <robertmhaas@gmail.com> wrote:
On Fri, Apr 23, 2010 at 11:27 PM, Rod Taylor <pg@rbt.ca> wrote:
Is there any particular reason why the citext module doesn't have
citext_pattern_ops operator family?You forgot to send in the patch. :-)
...Robert
Yes, someone implementing this would be greatly appreciated, especially
since I've just started using this datatype. ;)
Thom