'PostgreSQL accent + case insensitive search

I'm looking for a way to support with good performances case insensitive + accent insensitive search. Till now we had no issue on this using MSSql server, on Oracle we had to use OracleText, and now we need it on PostgreSQL.

I've found this post about it, but we need to combine it with case insensitive. We also need to use indexes, otherwise performances could be impacted. Any real experience about the best approach for large databases?

postgresqldatabase-designindexingfull-text-searchcase-insensitive


Solution 1:[1]

Full-Text-Search Dictionary that Unaccent case-insensitive

FTS is naturally case-insensitive by default,

Converting tokens into lexemes. A lexeme is a string, just like a token, but it has been normalized so that different forms of the same word are made alike. For example, normalization almost always includes folding upper-case letters to lower-case, and often involves removal of suffixes (such as s or es in English).

And you can define your own dictionary using unaccent, 

CREATE EXTENSION unaccent;

CREATE TEXT SEARCH CONFIGURATION mydict ( COPY = simple );
ALTER TEXT SEARCH CONFIGURATION mydict
  ALTER MAPPING FOR hword, hword_part, word
  WITH unaccent, simple;

Which you can then index with a functional index,

-- Just some sample data...
CREATE TABLE myTable ( myCol )
  AS VALUES ('fóó bar baz'),('qux quz');

-- No index required, but feel free to create one
CREATE INDEX ON myTable
  USING GIST (to_tsvector('mydict', myCol));

You can now query it very simply

SELECT *
FROM myTable
WHERE to_tsvector('mydict', myCol) @@ 'foo & bar'

    mycol    
-------------
 fóó bar baz
(1 row)

See also

Sources

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Source: Stack Overflow

Solution Source
Solution 1 Evan Carroll

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