Alan Hodgson wrote on 20.06.2012 19:39:
I'm curious how is wildcards at both ends implemented, e.g. LIKE '%str%'
How efficient is it if that's the only search criteria against a large
table? how much does indexing the column help and roughly how much more
space is needed for the index?
Indexing helps not at all. If the search string starts with a wildcard you
will always get a sequential scan of the whole table.
Not necessarily: http://www.depesz.com/2011/02/19/waiting-for-9-1-faster-likeilike/
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