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Nominatim/lib-sql/tokenizer/icu_tokenizer.sql
Sarah Hoffmann bd7c7ddad0 icu tokenizer: switch to matching against partial names
When matching address parts from addr:* tags against place names,
the address names where so far converted to full names and compared
those to the place names. This can become problematic with the new
ICU tokenizer once we introduce creation of different variants
depending on the place name context. It wouldn't be clear which
variant to produce to get a match, so we would have to create all of
them. To work around this issue, switch to using the partial terms
for matching. This introduces a larger fuzziness between matches but
that shouldn't be a problem because matching is always geographically
restricted.

The search terms created for address parts have a different problem:
they are already created before we even know if they are going to be
used. This can lead to spurious entries in the word table, which slows
down searching. This problem can also be circumvented by using only
partial terms for the search terms. In terms of searching that means
that the address terms would not get the full-word boost, but given
that the case where an address part does not exist as an OSM object
should be the exception, this is likely acceptable.
2021-09-27 11:36:19 +02:00

196 lines
5.2 KiB
PL/PgSQL

-- Get tokens used for searching the given place.
--
-- These are the tokens that will be saved in the search_name table.
CREATE OR REPLACE FUNCTION token_get_name_search_tokens(info JSONB)
RETURNS INTEGER[]
AS $$
SELECT (info->>'names')::INTEGER[]
$$ LANGUAGE SQL IMMUTABLE STRICT;
-- Get tokens for matching the place name against others.
--
-- This should usually be restricted to full name tokens.
CREATE OR REPLACE FUNCTION token_get_name_match_tokens(info JSONB)
RETURNS INTEGER[]
AS $$
SELECT (info->>'names')::INTEGER[]
$$ LANGUAGE SQL IMMUTABLE STRICT;
-- Return the housenumber tokens applicable for the place.
CREATE OR REPLACE FUNCTION token_get_housenumber_search_tokens(info JSONB)
RETURNS INTEGER[]
AS $$
SELECT (info->>'hnr_tokens')::INTEGER[]
$$ LANGUAGE SQL IMMUTABLE STRICT;
-- Return the housenumber in the form that it can be matched during search.
CREATE OR REPLACE FUNCTION token_normalized_housenumber(info JSONB)
RETURNS TEXT
AS $$
SELECT info->>'hnr';
$$ LANGUAGE SQL IMMUTABLE STRICT;
CREATE OR REPLACE FUNCTION token_has_addr_street(info JSONB)
RETURNS BOOLEAN
AS $$
SELECT info->>'street' is not null;
$$ LANGUAGE SQL IMMUTABLE;
CREATE OR REPLACE FUNCTION token_has_addr_place(info JSONB)
RETURNS BOOLEAN
AS $$
SELECT info->>'place' is not null;
$$ LANGUAGE SQL IMMUTABLE;
CREATE OR REPLACE FUNCTION token_matches_street(info JSONB, street_tokens INTEGER[])
RETURNS BOOLEAN
AS $$
SELECT (info->>'street')::INTEGER[] <@ street_tokens
$$ LANGUAGE SQL IMMUTABLE STRICT;
CREATE OR REPLACE FUNCTION token_matches_place(info JSONB, place_tokens INTEGER[])
RETURNS BOOLEAN
AS $$
SELECT (info->>'place')::INTEGER[] <@ place_tokens
$$ LANGUAGE SQL IMMUTABLE STRICT;
CREATE OR REPLACE FUNCTION token_addr_place_search_tokens(info JSONB)
RETURNS INTEGER[]
AS $$
SELECT (info->>'place')::INTEGER[]
$$ LANGUAGE SQL IMMUTABLE STRICT;
CREATE OR REPLACE FUNCTION token_get_address_keys(info JSONB)
RETURNS SETOF TEXT
AS $$
SELECT * FROM jsonb_object_keys(info->'addr');
$$ LANGUAGE SQL IMMUTABLE STRICT;
CREATE OR REPLACE FUNCTION token_get_address_search_tokens(info JSONB, key TEXT)
RETURNS INTEGER[]
AS $$
SELECT (info->'addr'->>key)::INTEGER[];
$$ LANGUAGE SQL IMMUTABLE STRICT;
CREATE OR REPLACE FUNCTION token_matches_address(info JSONB, key TEXT, tokens INTEGER[])
RETURNS BOOLEAN
AS $$
SELECT (info->'addr'->>key)::INTEGER[] <@ tokens;
$$ LANGUAGE SQL IMMUTABLE STRICT;
CREATE OR REPLACE FUNCTION token_normalized_postcode(postcode TEXT)
RETURNS TEXT
AS $$
SELECT CASE WHEN postcode SIMILAR TO '%(,|;)%' THEN NULL ELSE upper(trim(postcode))END;
$$ LANGUAGE SQL IMMUTABLE STRICT;
-- Return token info that should be saved permanently in the database.
CREATE OR REPLACE FUNCTION token_strip_info(info JSONB)
RETURNS JSONB
AS $$
SELECT NULL::JSONB;
$$ LANGUAGE SQL IMMUTABLE STRICT;
--------------- private functions ----------------------------------------------
CREATE OR REPLACE FUNCTION getorcreate_full_word(norm_term TEXT, lookup_terms TEXT[],
OUT full_token INT,
OUT partial_tokens INT[])
AS $$
DECLARE
partial_terms TEXT[] = '{}'::TEXT[];
term TEXT;
term_id INTEGER;
term_count INTEGER;
BEGIN
SELECT min(word_id) INTO full_token
FROM word WHERE word = norm_term and type = 'W';
IF full_token IS NULL THEN
full_token := nextval('seq_word');
INSERT INTO word (word_id, word_token, type, word, info)
SELECT full_token, lookup_term, 'W', norm_term,
json_build_object('count', 0)
FROM unnest(lookup_terms) as lookup_term;
END IF;
FOR term IN SELECT unnest(string_to_array(unnest(lookup_terms), ' ')) LOOP
term := trim(term);
IF NOT (ARRAY[term] <@ partial_terms) THEN
partial_terms := partial_terms || term;
END IF;
END LOOP;
partial_tokens := '{}'::INT[];
FOR term IN SELECT unnest(partial_terms) LOOP
SELECT min(word_id), max(info->>'count') INTO term_id, term_count
FROM word WHERE word_token = term and type = 'w';
IF term_id IS NULL THEN
term_id := nextval('seq_word');
term_count := 0;
INSERT INTO word (word_id, word_token, type, info)
VALUES (term_id, term, 'w', json_build_object('count', term_count));
END IF;
partial_tokens := array_merge(partial_tokens, ARRAY[term_id]);
END LOOP;
END;
$$
LANGUAGE plpgsql;
CREATE OR REPLACE FUNCTION getorcreate_partial_word(partial TEXT)
RETURNS INTEGER
AS $$
DECLARE
token INTEGER;
BEGIN
SELECT min(word_id) INTO token
FROM word WHERE word_token = partial and type = 'w';
IF token IS NULL THEN
token := nextval('seq_word');
INSERT INTO word (word_id, word_token, type, info)
VALUES (token, partial, 'w', json_build_object('count', 0));
END IF;
RETURN token;
END;
$$
LANGUAGE plpgsql;
CREATE OR REPLACE FUNCTION getorcreate_hnr_id(lookup_term TEXT)
RETURNS INTEGER
AS $$
DECLARE
return_id INTEGER;
BEGIN
SELECT min(word_id) INTO return_id FROM word
WHERE word_token = lookup_term and type = 'H';
IF return_id IS NULL THEN
return_id := nextval('seq_word');
INSERT INTO word (word_id, word_token, type)
VALUES (return_id, lookup_term, 'H');
END IF;
RETURN return_id;
END;
$$
LANGUAGE plpgsql;