Thread: ^@ operator for text
The following documentation comment has been logged on the website: Page: https://www.postgresql.org/docs/14/functions-string.html Description: In the new documentation https://www.postgresql.org/docs/14/functions-string.html you again lost information about ^@ operator for text and keep information about only function starts_with on which this operator is based. But ^@ is very important, because it can be accelerated by special index SP-GIST index. https://www.postgresql.org/docs/14/spgist-builtin-opclasses.html The task to filter text strings by prefix is rather common and using ^@ and SP-GIST is the best solution for this (rather options is to use starts_with without index acceleration or use LIKE construction with SP-GIST, which more complex (need to mention C locales), overengeniered and may be more slow). As I say the filtering text by prefix is very common task, but information about the best method is absent now.
PG Doc comments form <noreply@postgresql.org> writes: > In the new documentation > https://www.postgresql.org/docs/14/functions-string.html > you again lost information about ^@ operator for text and keep information > about only function starts_with on which this operator is based. "Again"? It was never there before, cf https://git.postgresql.org/gitweb/?p=postgresql.git&a=commitdiff&h=710d90da1 I did do something about this recently, though: https://git.postgresql.org/gitweb/?p=postgresql.git&a=commitdiff&h=2ae5d72f0 regards, tom lane
> 23 дек. 2021 г., в 18:18, Tom Lane <tgl@sss.pgh.pa.us> написал(а): > > PG Doc comments form <noreply@postgresql.org> writes: >> In the new documentation >> https://www.postgresql.org/docs/14/functions-string.html >> you again lost information about ^@ operator for text and keep information >> about only function starts_with on which this operator is based. > > "Again"? It was never there before, cf > > https://git.postgresql.org/gitweb/?p=postgresql.git&a=commitdiff&h=710d90da1 > > I did do something about this recently, though: > > https://git.postgresql.org/gitweb/?p=postgresql.git&a=commitdiff&h=2ae5d72f0 > > regards, tom lane I think need to mention that the main benefits of this operator (vs function starts_with) is the using with special SP-GISTindex. So searching and filtering can be indexed.
=?utf-8?B?0J7Qu9C10LMg0KHQsNC80L7QudC70L7Qsg==?= <splarv@ya.ru> writes: > 23 дек. 2021 г., в 18:18, Tom Lane <tgl@sss.pgh.pa.us> написал(а): >> I did do something about this recently, though: >> https://git.postgresql.org/gitweb/?p=postgresql.git&a=commitdiff&h=2ae5d72f0 > I think need to mention that the main benefits of this operator (vs function starts_with) is the using with special SP-GISTindex. So searching and filtering can be indexed. Not really true anymore, see a148f8bc0. regards, tom lane