On Nov 17, 2014, at 12:55 PM, Robert DiFalco wrote:
> SELECT * FROM MyTable WHERE upper(FullName) LIKE upper('%John%');
>
> That said, which would be the best extension module to use? A "gist" index on the uppercased column? Or something else? Thanks!
Performance wise, I think a function index would probably be the best:
CREATE INDEX mytable_lower_fullname_idx ON mytable(lower(fullname));
SELECT * FROM mytable WHERE lower(fullname) LIKE lower('%john%');
The only reason why I use `lower` and not `upper` is that it's easier to look at when dealing with debugging and sample queries.
I'd bench against GIN and GIST, but I think this will work the best.
The reason is that GIN/GIST use language patterns to simplify the index. so they work great on "words"
select plainto_tsquery('doing watching reading programming');
'watch' & 'read' & 'program'
but not so great on "names":
select plainto_tsquery('john doe');
'john' & 'doe'
select plainto_tsquery('jon doe');
'jon' & 'doe
So you'll get a bit more overhead on the match and you won't get a smaller index (which is why they're great for fulltext)
The search execution might turn out to be much faster. If so, i'd love to know. But doing a lower() search on a lower() function index has always been ridiculously fast for me.
This only goes for names though. If you're searching other fields, then another search method might be considerably better.
--
Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-general
