BUG #14745: to_tsvector(regconfig, json[b]) is NOT immutable

007reader@gmail.com writes:

According to https://www.postgresql.org/about/news/1763/ Beta 2 marked
to_tsvector(regconfig, json[b]) immutable, but it still doesn't work, at
least in the docker version of Beta 2. Here is the result:

create table test (j JSON, jb JSONB);
CREATE TABLE

create index j_ixd on test using gin(to_tsvector(j));
ERROR: functions in index expression must be marked IMMUTABLE

create index jb_ixd on test using gin(to_tsvector(jb));
ERROR: functions in index expression must be marked IMMUTABLE

Um, but that's not the two-argument version of to_tsvector.
You need something like

regression=# create index j_ixd on test using gin(to_tsvector('english', j));
CREATE INDEX
regression=# create index j_ixd2 on test using gin(to_tsvector('english', jb));
CREATE INDEX

The point here is that the single-argument versions are affected by
the configuration setting default_text_search_config, so they can't
be used in an index. Nailing down which tsconfig to use makes them
indexable.

regards, tom lane

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On Sun, Jul 16, 2017 at 11:10 AM, <007reader@gmail.com> wrote:

The following bug has been logged on the website:

Bug reference: 14745
Logged by: Bob Jones
Email address: 007reader@gmail.com
PostgreSQL version: 10beta2
Operating system: Debian in Docker container
Description:

According to https://www.postgresql.org/about/news/1763/ Beta 2 marked
to_tsvector(regconfig, json[b]) immutable, but it still doesn't work, at
least in the docker version of Beta 2. Here is the result:

create table test (j JSON, jb JSONB);
CREATE TABLE

create index j_ixd on test using gin(to_tsvector(j));
ERROR: functions in index expression must be marked IMMUTABLE

to_tsvector(regconfig, json[b]) and to_tsvector(json[b]) are not the same
thing.

Only the first is immutable, you are using the second.

Cheers,

Jeff