indexing - postgresql full text search function syntax -


in postgres database have table table1 , column column1 type text. , created index column create index idx_column1 on table1 using gin (to_tsvector('english', column1));

question is, why when execute query

select * table1 to_tsvector('english', column1) @@ to_tsquery('searchedtext')

index used, query index not used

select * table1 ts_match_vq(to_tsvector('english', column1),to_tsquery('searchedtext'))

wild guess:

vector @@ query defined 

create operator @@(   procedure = ts_match_vq,   leftarg = tsvector,   rightarg = tsquery,   commutator = @@,   restrict = tsmatchsel,   join = tsmatchjoinsel);

looking @ tsmatchjoinsel there quite lot going on (don't ask me what, kind of c way beyond me....) if go through different functions, there calculations involved. when using ts_match_vq directly, bypass these calculations. that's why ts_match_vq never mentioned in docs , should use @@ since takes care of calling right functions , stuff goes it.


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