Example for Full-Text Search Index doesn't work

[Christophe Pettus]

The example given for creating an index on a to_tsvector() call doesn't actually work, since to_tsvector() is not immutable (the results of it can change with changes to the underlying dictionaries it is ruled it is built on).

xof=# create table t (z text);
CREATE TABLE
xof=# create index on t(to_tsvector(z));
ERROR:  functions in index expression must be marked IMMUTABLE

(As a note, indexes on tsvectors should be GIN indexes rather than B-tree.)

For documentation purposes, I'd suggest pointing the reader to the PostgreSQL documentation that describes how to handle this situation.

[Christophe Pettus]

Documentation patch available at ​https://github.com/pgexperts/django/tree/ticket_26684_1_10.

[Christophe Pettus]

Documentation patch pull request submitted.

[Tim Graham]

A ticket isn't marked fixed until the patch is committed.

[Tim Graham <timograham@…>]

In 9210752:

Fixed #26684 -- Removed incorrect index example in docs/ref/contrib/postgres/search.txt.

[Tim Graham <timograham@…>]

In 3e1c8fc:

[1.10.x] Fixed #26684 -- Removed incorrect index example in docs/ref/contrib/postgres/search.txt.

Backport of 92107522ed3568740ec7c3597db50b5c3a6e84d3 from master