[dba-VB] LINQ Compiled Query

Gustav Brock gustav at cactus.dk
Sun Jan 9 11:30:04 CST 2011


Hi Shamil

I have no idea - and things may have evolved from 2008 to 2010.
Perhaps the only "trick" is to wrap the LINQ query in a static class?
But no ... I browsed a little and found this from a year ago:

EF 4.0 & compiled queries & performance
http://social.msdn.microsoft.com/Forums/en/adonetefx/thread/0c07e1d6-7db6-4348-b106-e576d3153b70

which demonstrates a dramatic speed increase for repeated runs of a compiled query.
It also provides this link which seems to explain what is going on:

Precompiling LINQ Queries by Julie Lerman
http://msdn.microsoft.com/en-gb/magazine/ee336024.aspx

/gustav

PS: All MSDN Magazines can be browsed from here:
http://msdn.microsoft.com/en-gb/magazine/ee310108.aspx


>>> shamil at smsconsulting.spb.ru 09-01-2011 16:55 >>>
Hi Gustav --

<<<
However, if you have a crucial query in, say, a loop it could be worth the
efforts.
>>> 
Shouldn't LINQ be "smart enough" to not rebuild dynamic queries when that
used in a loop? (of course if LINQ expression is not forcibly destroyed (by
developer) at the end of every cycle iteration).

I'd guess even if they get forcibly destoryed LINQ coudl somehow keep
parsed&compiled LINQ expression cached...

It's a very smart technology... (nothing new - all the principles used in
(P)LINQ are known for years but that's the first time such a technology
released to the business applications developers?)

Thank you.

--
Shamil
 
-----Original Message-----
From: dba-vb-bounces at databaseadvisors.com 
[mailto:dba-vb-bounces at databaseadvisors.com] On Behalf Of Gustav Brock
Sent: 9 ?????? 2011 ?. 18:00
To: dba-vb at databaseadvisors.com 
Subject: Re: [dba-VB] LINQ Compiled Query

Hi Shamil

Yes, I noticed that comment and think it is valid. 
However, if you have a crucial query in, say, a loop it could be worth the
efforts.

/gustav


>>> shamil at smsconsulting.spb.ru 09-01-2011 15:20 >>>
Hi Gustav --

No, I didn't. 

One of comments says: "I feel this compiled query approach is cumbersome.
Image your application has 100 linq queries, you have to create 100 helper
classes, and another 100 static functions. I wish Microsoft provides an
easily way, maybe some syntax sugar, or some more magics in DataContent, to
make programmer life easier. "

Thank you.

--
Shamil
 
-----Original Message-----
From: dba-vb-bounces at databaseadvisors.com 
[mailto:dba-vb-bounces at databaseadvisors.com] On Behalf Of Gustav Brock
Sent: 9 ?????? 2011 ?. 17:12
To: dba-vb at databaseadvisors.com 
Subject: [dba-VB] LINQ Compiled Query

Hi all

Has anyone tested this technique out:
http://www.blog.ingenuitynow.net/15+Minutes+On+LINQ+Compiled+Queries.aspx 

It looks quite simple to implement.

/gustav






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