Any method materialize object and decrease performance
Description
Any() method in linq cause object materialization. That behaviour can decrease performance if that object is big. I think that it would be better to make some Count() sql query to detect if there is any object.
I have mesured time of invoction of two methods: Any() and Count() and there are results:
code
time
474ms
31ms
Environment
None
Activity
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Alex Zaytsev
September 3, 2014 at 12:41 AM
I mean at the select clause.
Ricardo Peres
September 3, 2014 at 12:23 AM
Yes, for collections. From the manual:
from Cat cat where exists elements(cat.kittens)
I see your point... maybe a more intelligent solution would be to translate .Any() to .Take(1).SingleOrDefault()?
Alex Zaytsev
September 3, 2014 at 12:19 AM
(edited)
Does `exists` work in HQL?
Ricardo Peres
September 2, 2014 at 10:54 PM
Any() should be identical to SQL EXISTS. Count() is a COUNT. EXISTS has better performance, because it stops if at least one element exists. Maybe there's something else. Can you submit a test?
Minor
Any() method in linq cause object materialization. That behaviour can decrease performance if that object is big. I think that it would be better to make some Count() sql query to detect if there is any object.
I have mesured time of invoction of two methods: Any() and Count() and there are results:
code
time
474ms
31ms