ERROR: data type text[] has no default operator class for access method "gist"

Question

Whenever I try to try to create a GIST index on text[], I get the above error.

CREATE TABLE bar(f)
AS VALUES
  (ARRAY['foo','bar','baz']);

CREATE INDEX ON bar USING gist(f);

ERROR:  data type text[] has no default operator class for access method "gist"
HINT:  You must specify an operator class for the index or define a default operator class for the data type.

I'm trying to create an Exclusion Constraint on bar, so I need a GIST index.

Answer 1

smlar Extension

I was able to create a gist index on a text[] column using the smlar extension (written by Teodor Sigaev of text search fame)

# git clone git://sigaev.ru/smlar.git
# cd smlar/
# PATH=/usr/pgsql-9.6/bin:$PATH make USE_PGXS=1
# PATH=/usr/pgsql-9.6/bin:$PATH make USE_PGXS=1 install
# psql

postgres=# create extension smlar;
postgres=# create index on bar using gist(f _text_sml_ops);

Answer 2

Another option would be to create the index converting the column to ts_vector, this way you will not need to install smlar.

create index on bar using gist(array_to_tsvector(f));

When using the index, make sure you're using operations supported by tsvector, such as:

select * from bar where to_tsquery('search_value') @@ array_to_tsvector(f);