Rails core - Mar 2013 - Use = instead of BETWEEN when a date range's begin and end are the same

Hi all,

Was wondering if it would be worth adding a predicate optimization for when 
a date range''s `begin` and `end` are equal?
    

Post.where(:published_at => Date.new(2012,4,25)..Date.new(2012,4,25))

#=> Post Load (3.0ms)  SELECT `posts`.* FROM `posts` WHERE 
(`posts`.`published_at` BETWEEN ''2012-04-25'' AND
''2012-04-25'')



is a tiny bit slower than

Post.where(:published_at => Date.new(2012,4,25))

#=> Post Load (2.7ms)  SELECT `posts`.* FROM `posts` WHERE 
`posts`.`published_at` = ''2012-04-25''



We could add something like this, somewhere in *
active_record/relation/query_methods.rb*:

if val.is_a?(Range)
  return val.begin == val.end ? val.begin : val
end



Please let me know if it''s worthwhile, and I''ll submit a pull
request.


Best,
Nathan

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Since this is a perf PR, I think it''d be nice to see some benchmarks to
be
absolutely sure.

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I think this isn''t worth the if clause performance degradation from all
queries. This scenario doesn''t happen quite often.

Em domingo, 17 de março de 2013 07h44min27s UTC-3, Nathan Broadbent 
escreveu:
>
> Hi all,
>
> Was wondering if it would be worth adding a predicate optimization for 
> when a date range''s `begin` and `end` are equal?
>     
>
> Post.where(:published_at => Date.new(2012,4,25)..Date.new(2012,4,25))
>
> #=> Post Load (3.0ms)  SELECT `posts`.* FROM `posts` WHERE 
> (`posts`.`published_at` BETWEEN ''2012-04-25'' AND
''2012-04-25'')
>
>
>
> is a tiny bit slower than
>
> Post.where(:published_at => Date.new(2012,4,25))
>
> #=> Post Load (2.7ms)  SELECT `posts`.* FROM `posts` WHERE 
> `posts`.`published_at` = ''2012-04-25''
>
>
>
> We could add something like this, somewhere in *
> active_record/relation/query_methods.rb*:
>
> if val.is_a?(Range)
>   return val.begin == val.end ? val.begin : val
> end
>
>
>
> Please let me know if it''s worthwhile, and I''ll submit a
pull request.
>
>
> Best,
> Nathan
>
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Answer to this is "database specific and depending if there is an index on 
the column or not and how that index is organized",

some database-storage engine-index type combinations will opt a full table 
table scan instead of index scan/fetch when "between" happens as
opposed to
a "=" query which would imply severe performance degradations in
specific
cases. Perhaps this can be addressed at adapter level or as a configuration 
option?


On Monday, March 18, 2013 7:27:09 AM UTC+1, Godfrey Chan
wrote:
>
> Since this is a perf PR, I think it''d be nice to see some
benchmarks to be
> absolutely sure.
>
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