Re: Prefix operator for text and spgist support - Mailing list pgsql-hackers

From Ildus Kurbangaliev
Subject Re: Prefix operator for text and spgist support
Date
Msg-id 20180416155036.36070396@wp.localdomain
Whole thread Raw
In response to Re: Prefix operator for text and spgist support  (Emre Hasegeli <emre@hasegeli.com>)
List pgsql-hackers
On Mon, 16 Apr 2018 12:45:23 +0200
Emre Hasegeli <emre@hasegeli.com> wrote:

> > Thank you, pushed with some editorization and renaming
> > text_startswith to starts_with  
> 
> I am sorry for not noticing this before, but what is the point of this
> operator?  It seems to me we are only making the prefix searching
> business, which is already complicated, more complicated.

Hi.

> 
> Also, the new operator is not documented on SQL String Functions and
> Operators table.  It is not supported by btree text_pattern_ops or
> btree indexes with COLLATE "C".  It is not defined for "citext", so
> people would get wrong results.  It doesn't use pg_trgm indexes
> whereas LIKE can.

It is mentioned in documentation, look for "starts_with" function.
Currently it's working with spgist indexes which fact is pointed out in
the documentation too. I was going to add btree support but it would
require a new strategy so it will be matter of another patch. I think
this operator could be used in LIKE instead of current weird comparison
operators.

-- 
---
Ildus Kurbangaliev
Postgres Professional: http://www.postgrespro.com
Russian Postgres Company


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