Re: Optimizing Postgresql ILIKE while query

> On 22 Oct 2018, at 7:56, aman gupta <amangpt89@gmail.com> wrote:
>
> Issue:
>
> We have the base table which contains 22M records and we created a view on top of it while querying the view with
ILIKEclause it took 44 seconds and with LIKE Clause 20 Seconds 
>
> Query:
>
> fm_db_custom_db=# EXPLAIN (ANALYZE, TIMING OFF)
> select
destination,hostname,inputfilename,inputtime,logicalservername,outputfilename,outputtime,processinglink,source,totalinputbytes,totalinputcdrs,totaloutputbytes,totaloutputcdrs
frommmsuper.test_20m_view  where inputfilename ilike '%SDPOUTPUTCDR_4001_BLSDP09_ADM_4997_18-10-15-02549.ASN%'; 

Perhaps, when you have a question about timing, you shouldn't turn off the timing in the query plan? Now we can't see
wherethe time is spent. 

> <LIKE_Clause_ILIKE_Clause_Postgres_Response.txt>

That's all sequential scans that each remove a significant amount of rows. That probably costs a significant amount of
timeto do. 

It looks like you don't have any indices on the underlying table(s) at all. I'd start there and then look at the ILIKE
problemagain. By that time, Pavel's suggestion for a trigram index on that text field is probably spot-on. 

Alban Hertroys
--
If you can't see the forest for the trees,
cut the trees and you'll find there is no forest.