Several PostgreSQL extensions can help implement word segmentation and quick query of data

In PostgreSQL databases, there are several extensions that can help implement word segmentation and quick query of data, especially when dealing with full-text search and text analysis. Here are a few commonly used extensions:

1. pg_trgm

The pg_trgm (Trigram) extension is a powerful tool in PostgreSQL that can be calculatedStringSimilarity between to achieve fast text search. It supports indexes and queries based on trigram (3-gram) and can be used for fuzzy matching and word participle searches.

• Install:

CREATE EXTENSION pg_trgm;

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• Example:
  Use pg_trgm to create GIN or GiST indexes for text fields to improve search performance.

CREATE INDEX trgm_idx ON my_table USING GIN (my_column gin_trgm_ops);

SELECT * FROM my_table WHERE my_column ILIKE '%search_term%';

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This will speed up fuzzy search via trigram index

2. tsvector and tsquery (Full-Text Search)

The full-text search function that comes with postgreSQL is implemented through the tsvector and tsquery types. These types support word segmentation and indexing of text, enabling fast full-text search.

• Example:

CREATE TABLE documents (
     id SERIAL PRIMARY KEY,
     content TEXT,
     tsv_content TSVECTOR
 );

 -- Create a GIN index for full text search
 CREATE INDEX idx_tsv_content ON documents USING GIN (tsv_content);

 -- Convert text to tsvector for indexing
 UPDATE documents SET tsv_content = to_tsvector('english', content);

 -- Search for example
 SELECT * FROM documents WHERE tsv_content @@ to_tsquery('search_term');

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You can use to_tsvector to convert text fields to tsvector type and create a GIN index to speed up searches.

3. unaccent

The unaccent extension removes accents from text, which is for handling multilingualText SearchVery useful.

• Install:

CREATE EXTENSION unaccent;

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• Example:

SELECT unaccent('café'); -- Output: cafe

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In full-text search, text can be processed through unaccent and then indexed, thus achieving a looser match of accent characters.

4. pgroonga

pgroonga is a full-featured full-text search extension that supports full-text search in multiple languages, andperformancePowerful, especially suitable for scenarios where non-Latin characters are required.

• Install:

-- Install the pgroonga extension
 CREATE EXTENSION pgroonga;

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• Example:

CREATE TABLE memos (
     id SERIAL PRIMARY KEY,
     content TEXT
 );

 -- Create a pgroonga index
 CREATE INDEX pgroonga_idx ON memos USING pgroonga (content);

 -- Search with pgroonga
 SELECT * FROM memos WHERE content &@~ 'search term';

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pgroonga supports full-text search and is very effective for processing multilingual data.

5. zhparser

For Chinese word segmentation, zhparser is a special extension, combining PostgreSQL's full-text search function, which can effectively process word segmentation and search of Chinese text.

• Install:
  Requires the zhparser extension installed on PostgreSQL (may require compilation and installation)

CREATE EXTENSION zhparser;

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• Example:

-- Set the full text search configuration to Chinese
 CREATE TEXT SEARCH CONFIGURATION chinese (PARSER = zhparser);
 ALTER TEXT SEARCH CONFIGURATION chinese ADD MAPPING FOR n,v,a,i,e,l WITH simple;

 -- Create tsvector index
 CREATE INDEX idx_content ON my_table USING GIN (to_tsvector('chinese', content));

 -- search
 SELECT * FROM my_table WHERE to_tsvector('chinese', content) @@ to_tsquery('chinese', 'search term');

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6. rum

rum is an index extension of PostgreSQL, which is particularly suitable for processing extensions such as pg_trgm and tsvector, which can significantly improve the query speed and sorting performance of full-text search.

• Install:

CREATE EXTENSION rum;

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• Example:

CREATE INDEX rum_idx ON documents USING RUM (tsv_content rum_tsvector_ops);

SELECT * FROM documents WHERE tsv_content @@ to_tsquery('search_term') ORDER BY ts_rank(tsv_content, to_tsquery('search_term'));

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The rum extension is more efficient than GIN indexes in order to sort and ranking calculations.

Summarize

• If you need fuzzy searches or simple participle, pg_trgm is a great choice.
• For complex full-text search requirements, you can use PostgreSQL's built-in tsvector and tsquery.
• If you are dealing with Chinese or other languages ​​that require special participle, zhparser and pgroonga are better choices.
• The rum extension can further improve the query and sorting performance of full-text search.