QA: text @@ text results don't match Postgres

[msirek]

From TSVector and TSQuery QA,

The following queries return different results on CRDB vs. Postgres:

SELECT  '(fat & rats)' @@ 'fats cats ate fat rats';
SELECT  '(fat | rats)' @@ 'fats cats ate fat rats';

Note that the default text search configuration in Postgres must be updated via:

SET default_text_search_config = 'pg_catalog.simple';

to make the Postgres configuration match the CRDB default (CRDB only supports 'simple').

According to Postgres docs,

The form text @@ text is equivalent to to_tsvector(x) @@ plainto_tsquery(y).

According to this rule, the above queries should be equivalent to:

SELECT to_tsvector('simple', '(fat & rats)') @@ plainto_tsquery('simple', 'fats cats ate fat rats');
SELECT to_tsvector('simple', '(fat | rats)') @@ plainto_tsquery('simple', 'fats cats ate fat rats');

But the results of these queries don't match eachother:

root@localhost:26257/defaultdb> SELECT  '(fat & rats)' @@ 'fats cats ate fat rats';
  ?column?
------------
     t
(1 row)

root@localhost:26257/defaultdb> SELECT to_tsvector('simple', '(fat & rats)') @@ plainto_tsquery('simple', 'fats cats ate fat rats');
  ?column?
------------
     f
(1 row)

root@localhost:26257/defaultdb> SELECT  '(fat | rats)' @@ 'fats cats ate fat rats';
  ?column?
------------
     t
(1 row)

root@localhost:26257/defaultdb> SELECT to_tsvector('simple', '(fat | rats)') @@ plainto_tsquery('simple', 'fats cats ate fat rats');
  ?column?
------------
     f
(1 row)

Jira issue: CRDB-25530