Re: [GENERAL] Special index for "like"-based query

On 12/30/2016 12:33 AM, David G. Johnston wrote:
> On Thu, Dec 29, 2016 at 4:21 PM, Job <Job@colliniconsulting.it
> <mailto:Job@colliniconsulting.it>>wrote:
>
>     Hello,
>
>     in Postgresql 9.6 we have a query running on a very large table
>     based, in some cases, on a like statement:
>
>     ... WHERE FIELD='CODE' OR FIELD LIKE 'CODE_%'
>
>     Which type of index can i create to speed to the search when the
>     "like" case happens?
>
>
> ​GIST​
>
> https://www.postgresql.org/docs/9.6/static/pgtrgm.html
>
> ​https://www.postgresql.org/docs/9.6/static/btree-gist.html
> ​

For prefix queries, it's also possible to use simple btree index with
varchar_pattern_ops.

https://www.postgresql.org/docs/9.6/static/indexes-opclass.html


regards

--
Tomas Vondra                  http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services