Re: Text search prefix matching and stop words
| От | Pavel Borisov |
|---|---|
| Тема | Re: Text search prefix matching and stop words |
| Дата | |
| Msg-id | CALT9ZEG-i0prBw5N7pMAPqL_Kj=g_xK-oKjumE6-q0TVvOfB4A@mail.gmail.com обсуждение исходный текст |
| Ответ на | Text search prefix matching and stop words ("Matthew Nelson" <mnelson@binarykeep.com>) |
| Ответы |
Re: Text search prefix matching and stop words
Re: Text search prefix matching and stop words Re: Text search prefix matching and stop words |
| Список | pgsql-bugs |
Prefix matching should not omit stop words, as matching lexemes may legitimately begin with stop words.
# select to_tsquery('english', 'over:*') @@ to_tsvector('english', 'overhaul');
NOTICE: text-search query contains only stop words or doesn't contain lexemes, ignored
?column?
----------
f
(1 row)
I noticed this after implementing interactive, incremental search in an application. As the user typed "overhaul," with each successive character executing a search, "ove" and "overh" matched a particular document, but "over" did not.
Big thanks for the reporting!
I am not sure that it is a bug. I think this is a way how to_tsquery conversion work: stopwords first then template processing.
If you want to process successive characters typing, you can use casting to tsvector type until input is not finished
'over:*'::tsquery;
and when the user finishes input then process the result via to_tsquery with stop words.
if we do to_tsquery in a way you described I expect it will never apply the stop-word filter on templated input as it can not be compared to stop words.
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