At 6:13 +0530 4/28/03, gamin wrote:
>I have one field (indexed) that can take 66 different values in a
>table of 500,000 rows. Earlier i had it set to char(3) and queries
>like
>
>select * from my_table where charfield like '3%' order by charfield limit 100;
>
>would showup in about 300 ms. I changed the field to not null enum
>(with the 66 values) and an identical query takes about 5500 ms. Is
>this sort of behaviour expected ??
I wouldn't say it's surprising. ENUM values are represented internally
as integers, so the LIKE pattern-match involves conversion of the values
to string form so that they can be compared to the pattern. Also, when
you had charfield represented as a string, if you had that column indexed,
LIKE can use the index if the pattern begins with a literal value, as
yours does.
>
>Thank you and regards
>
>G
--
Paul DuBois
http://www.kitebird.com/
sql, query
