Tsearch2 - is the full text engine, fully integrated into PostgreSQL RDBMS.

Main features

• Full online update
• Supports multiple table driven configurations
• flexible and rich linguistic support (dictionaries, stop words), thesaurus
• full multibyte (UTF-8) support
• Sophisticated ranking functions with support of proximity and structure information (rank, rank_cd)
• Index support (GiST and Gin) with concurrency and recovery support
• Rich query language with query rewriting support
• Headline support (text fragments with highlighted search terms)
• Ability to plug-in custom dictionaries and parsers
• Template generator for tsearch2 dictionaries with snowball stemmer support
• It is mature (5 years of development)

Tsearch2, in a nutshell, provides FTS operator (contains) for the new data types, representing document (tsvector) and query (tsquery). Table driven configuration allows creation of custom searches using standard SQL commands.

tsvector is a searchable data type, representing document. It is a set of unique words along with their positional information in the document, organized in a special structure optimized for fast access and lookup. Each entry could be labelled to reflect its importance in document.

tsquery is a data type for textual queries with support of boolean operators. It consists of lexemes (optionally labelled) with boolean operators between.

Table driven configuration allows to specify:

• parser, which used to break document onto lexemes
• what lexemes to index and the way they are processed
• dictionaries to be used along with stop words recognition.


visit Tsearch2
Tsearch2 was visited : 44 times