On 6/20/2012 12:10 PM, Sam Z J wrote:
Hi all I'm curious how is wildcards at both ends implemented, e.g. LIKE '%str%' How efficient is it if that's the only search criteria against a large table? how much does indexing the column help and roughly how much more space is needed for the index? if the answers are too long, please point me to the relavant text =D thanks -- Zhongshi (Sam) Jiang sammyjiang721@xxxxxxxxx <mailto:sammyjiang721@xxxxxxxxx>
An index will not be used for that kind of search. PG will scan the entire table to find matches. PG can only use an index if you have a search LIKE 'str%'
There are options like full text search, and pg_trgm that you might be able to use.
-Andy -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
