Re: Text search lexer's handling of hyphens and negatives - Mailing list pgsql-general

From Alan Hodgson
Subject Re: Text search lexer's handling of hyphens and negatives
Date
Msg-id 45772fae97692f848fa102b0ddb92ad0c6d6b5bc.camel@lists.simkin.ca
Whole thread Raw
In response to Re: Text search lexer's handling of hyphens and negatives  (raylu <lurayl@gmail.com>)
List pgsql-general
On Tue, 2019-10-15 at 20:34 -0700, raylu wrote:
On Tue, Oct 15, 2019 at 3:35 PM Alan Hodgson <
ahodgson@lists.simkin.ca
> wrote:
My company has found the pg_trm extension to be more useful for partial text searches than the full text functions. I don't know specifically how it might help with your hyphens but it would be worth testing. The docs actually suggest using them in conjunction in some cases.

We actually do use pg_trgm already for the names/titles of things.
Indexing the content with a trigram index and then doing
LOWER(content) LIKE '%789-xyz%' would certainly work, but
1. we'd have to do a little bit of finagling if we wanted to match on
word boundaries (don't match '6789-xyza' in the above example)
2. trigram indexes are pretty huge for long documents, which is why we
currently only use them for names/titles

We may give up and just use pg_trgm for contents if nothing else works
out but it feels like the text search lexer is _so_ close to what we
want.


Maybe you could have a trigger pull out those specific hypenated references into a separate column when the document is added or updated, and store/index those separately?

pgsql-general by date:

Previous
From: Adrian Klaver
Date:
Subject: Re: Analyze and vaccum
Next
From: Alexander Pyhalov
Date:
Subject: PostgreSQL memory usage