[rt-users] PostgreSQL full-text index default type: GiST or GIN

ktm at rice.edu ktm at rice.edu
Thu Mar 17 16:29:19 EDT 2016


I am working on an upgrade from 3.8.x to 4.4.x and I noticed the
following comment in the UPGRADING-4.2 file:

The full-text indexing defaults for PostgreSQL have changed; GiST is now
the suggested index, as well as storing data in a separate
AttachmentsIndex table.  Both changes improve lookup speed.  For
improved search performance, you may wish to drop existing C<tsvector>
and C<GIN> indexes on C<Attachments>, and re-generate the index using

I am curious about the benchmarks you used to make this determination?
In particular, the GIN fastscan option can dramatically improve search
performance in versions 9.4 and above. Here is a nice discussion:


In addition, GIN indexes are much smaller in PostgreSQL 9.4 and above.
So I am curious about the data that motivated the change to GiST.


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