Re: Why is there a tsquery data type?
От | Oleg Bartunov |
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Тема | Re: Why is there a tsquery data type? |
Дата | |
Msg-id | Pine.LNX.4.64.0708302102080.2767@sn.sai.msu.ru обсуждение исходный текст |
Ответ на | Re: Why is there a tsquery data type? (Bruce Momjian <bruce@momjian.us>) |
Список | pgsql-hackers |
On Thu, 30 Aug 2007, Bruce Momjian wrote: > Gregory Stark wrote: >> "Bruce Momjian" <bruce@momjian.us> writes: >> >>> There is no question things would be clearer with only one text search >>> data type. The only value I can see to having a tsquery data type is >>> that you can store a tsquery value in a column, but why would that be >>> much better than just storing it in a TEXT field? >> >> When you try storing a tsquery in a column does it alert you if you have an >> invalid syntax at that point? Storing it as text would mean not finding out >> until you try to use the query. > > Yes it does check syntax: > > test=> select 'lkjadsf kjfdsa'::tsquery; > ERROR: syntax error in tsearch query: "lkjadsf kjfdsa" > > A larger question is how many people store queries in the database to > make it worth the complexity. you forget about very powerfull query rewriting, which is table driven > >> Is converting a text query into the internal format faster or less memory >> intensive than converting text into the internal representation? When you run >> a query like "WHERE '...' @@ col" if there wasn't a tsquery data type then >> '...' would have to be parsed over and over again for each row. > > No, internally the TEXT string would be converted to something the > system could deal with for that query, which is probably what 99% of all > queries are going to do anyway by calling to_tsquery(). > > Regards, Oleg _____________________________________________________________ Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru), Sternberg Astronomical Institute, Moscow University, Russia Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/ phone: +007(495)939-16-83, +007(495)939-23-83
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