Re: Wrong plan sequential scan instead of an index one

[Richard Huxton <dev(at)archonet(dot)com>]

Gaetano Mendola wrote:
> The match 19 for '%pi%' is estimated, the real matches are:
>
> test=# select id from l_pvcp where value ilike '%pi%';
>  id
> - ----
>  62
> (1 row)
>
>
> test=#  select id from l_pvcp where value ilike 'pi';
>  id
> - ----
>  62
> (1 row)
>
> so one row in both cases, that's why I expect for both same plan.

Ah, but it's got no way of knowing what matches you'll get for 
'%anything%'. There's no easy way to get statistics for matching substrings.

--
  Richard Huxton
  Archonet Ltd