Rod Taylor <p...@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



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