Re: LIKE search and performance

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От James Mansion
Тема Re: LIKE search and performance
Дата
Msg-id 466733D1.1040308@mansionfamily.plus.com
обсуждение исходный текст
Ответ на Re: LIKE search and performance  (mark@mark.mielke.cc)
Ответы Re: LIKE search and performance  (mark@mark.mielke.cc)
Список pgsql-performance
mark@mark.mielke.cc wrote:
> What is a real life example where an intelligent and researched
> database application would issue a like or ilike query as their
> primary condition in a situation where they expected very high
> selectivity?
>
In my case the canonical example is to search against textual keys where
the search is
performed automatically if the user hs typed enough data and paused.  In
almost all
cases the '%' trails, and I'm looking for 'starts with' in effect.
usually the search will have
a specified upper number of returned rows, if that's an available
facility.  I realise in this
case that matching against the index does not allow the match count
unless we check
MVCC as we go, but I don't see why another thread can't be doing that.

James


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