> So we were advised to use "fulltextindex".- chunk
> this fields on single words and make new table with words and oids in
> it. After we made this table its size was 2940360 records. And I tried
> to measure the time:
>
> ....
>
> select f1.id from app_fti f1, app_fti f2 where f1.string~*'visual' and
> f2.string~*'basic' and f1.id=f2.id;
What is causing it to be so slow is the use of regular expression pattern
matching. For reasons I don't know, regular expression evaluation in a
query is fairly slow in PostgreSQL. But since you have (correctly, I think)
made a full text index, why do you still need to use regexp's ?
Replace the ~* operator in the query above with 'LIKE', and you should find
it several times faster.
Please let us know the results of your testing.
- Andrew
