Re: insensitive collations

you were exactly right. With client_encoding set to UTF8 it now works
correctly.

the transformation to do the LIKE or ILIKE on a nondeterministic ICU
collation CI_AS for which there is an otherwise identical deterministic
collation CS_AS is as shown below:

SELECT * FROM locations WHERE location LIKE 'midi-Pyr_n%ées'; -- what we
want to do
ERROR: nondeterministic collations are not supported for LIKE

-- explicitly collate with the CS_AS collation and then use ILIKE to get the
desired CI_AS behavior:
-- note that the single-character wildcard '_' matches either e or é, as
expected

SELECT * FROM locations WHERE location COLLATE SQL_Latin1_General_CP1_CS_AS
ILIKE 'midi-Pyr_n%ées';
location
---------------
Midi-Pyrénées
midi-Pyrénées
midi-Pyrenées
(3 rows)

EXPLAIN SELECT * FROM locations WHERE location COLLATE
SQL_Latin1_General_CP1_CS_AS ILIKE 'midi-Pyr_n%ées';
QUERY PLAN
-------------------------------------------------------------------------------
Bitmap Heap Scan on locations (cost=8.90..20.77 rows=1 width=516)
Filter: ((location)::text ~~* 'midi-Pyr_n%ées'::text)
-> Bitmap Index Scan on location_index (cost=0.00..8.89 rows=150
width=0)
(3 rows)

-----
Jim Finnerty, AWS, Amazon Aurora PostgreSQL
--
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