F.47. pg_tsparser — an extension for text search #
pg_tsparser
is a Postgres Pro extension for text search. This extension modifies the default text parsing strategy for words that include:
underscores
numbers and letters separated by the hyphen character
In addition to separate word parts returned by default, pg_tsparser
also returns the whole word.
F.47.1. Installation and Setup #
pg_tsparser
is included into the Postgres Pro distribution. To enable pg_tsparser
, once Postgres Pro is installed, create the pg_tsparser
extension for each database you are planning to use:
CREATE EXTENSION pg_tsparser;
Once pg_tsparser
is enabled, you can create your own text search configuration. In addition to pg_tsparser
, you can use any available dictionary.
For example, you can create english_ts
configuration for the English language, as follows:
CREATE TEXT SEARCH CONFIGURATION english_ts ( PARSER = tsparser ); COMMENT ON TEXT SEARCH CONFIGURATION english_ts IS 'text search configuration for english language'; ALTER TEXT SEARCH CONFIGURATION english_ts ADD MAPPING FOR email, file, float, host, hword_numpart, int, numhword, numword, sfloat, uint, url, url_path, version WITH simple; ALTER TEXT SEARCH CONFIGURATION english_ts ADD MAPPING FOR asciiword, asciihword, hword_asciipart, word, hword, hword_part WITH english_stem;
F.47.2. Examples #
The following examples illustrate the difference in search results returned by pg_tsparser
and the default parser:
SELECT to_tsvector('english', 'pg_trgm') as def_parser, to_tsvector('english_ts', 'pg_trgm') as new_parser; def_parser | new_parser -----------------+----------------------------- 'pg':1 'trgm':2 | 'pg':2 'pg_trgm':1 'trgm':3 (1 row) SELECT to_tsvector('english', '123-abc') as def_parser, to_tsvector('english_ts', '123-abc') as new_parser; def_parser | new_parser -----------------+----------------------------- '123':1 'abc':2 | '123':2 '123-abc':1 'abc':3 (1 row) SELECT to_tsvector('english', 'rel-3.2-A') as def_parser, to_tsvector('english_ts', 'rel-3.2-A') as new_parser; def_parser | new_parser ------------------+------------------------------- '-3.2':2 'rel':1 | '3.2':3 'rel':2 'rel-3.2-a':1 (1 row)
See Also
F.47.3. Authors #
Postgres Professional, Moscow, Russia