http://ayende.comAyende @ RahienCopyright (C) Ayende Rahien 2004 - 2021 (c) 202660Steve, I would gladly take a patch for that. I don't consider this an easy problem http://ayende.com/3657/nh-prof-how-to-detect-select-n-1#comment13http://ayende.com/3657/nh-prof-how-to-detect-select-n-1#comment13Thu, 30 Oct 2008 22:12:20 GMTI don't understand why none of the ORMs have built-in support to dynamically detect and optimize N+1 in a live environment. The basics would be real easy to write - the ORM can correlate the "N" queries with the "+1" query, and prefetch batches of results when it detects a likely problem. Add in some statistics to enable smart decisions, and pretty soon you have the first ORM in the world to not care about N+1. http://ayende.com/3657/nh-prof-how-to-detect-select-n-1#comment12http://ayende.com/3657/nh-prof-how-to-detect-select-n-1#comment12Thu, 30 Oct 2008 17:01:59 GMTI don't think so. You don't have enough information there http://ayende.com/3657/nh-prof-how-to-detect-select-n-1#comment11http://ayende.com/3657/nh-prof-how-to-detect-select-n-1#comment11Wed, 29 Oct 2008 12:56:08 GMTWouldn't it be possible to catch N+1 using listeners? http://ayende.com/3657/nh-prof-how-to-detect-select-n-1#comment10http://ayende.com/3657/nh-prof-how-to-detect-select-n-1#comment10Wed, 29 Oct 2008 12:49:34 GMTNot wanting too pedantic but any 'magic numbers' (i.e. not 0 or 1) should be a constant at least. http://ayende.com/3657/nh-prof-how-to-detect-select-n-1#comment9http://ayende.com/3657/nh-prof-how-to-detect-select-n-1#comment9Fri, 24 Oct 2008 02:15:55 GMTScott, I intend on making this a commercial project. As such, I don't want to limit myself to people having R#. It is also a very different mindset than what R# is doing. The information is gathered at runtime, from the execution of the code, not from analyzing the source. http://ayende.com/3657/nh-prof-how-to-detect-select-n-1#comment8http://ayende.com/3657/nh-prof-how-to-detect-select-n-1#comment8Thu, 23 Oct 2008 18:40:47 GMTWhy not add these features to the NHibernate add-in for Resharper? I downloaded it recently and am added it. These could be warnings or something like that. http://ayende.com/3657/nh-prof-how-to-detect-select-n-1#comment7http://ayende.com/3657/nh-prof-how-to-detect-select-n-1#comment7Thu, 23 Oct 2008 16:06:30 GMTBryan, I don't need to worry about this, since NH produce predictable SQL for all scenarios http://ayende.com/3657/nh-prof-how-to-detect-select-n-1#comment6http://ayende.com/3657/nh-prof-how-to-detect-select-n-1#comment6Thu, 23 Oct 2008 13:29:52 GMTI had to pick a threshold, and 3 identical queries in the session seemed to be a good max to use. I don't want to have to false positives. http://ayende.com/3657/nh-prof-how-to-detect-select-n-1#comment5http://ayende.com/3657/nh-prof-how-to-detect-select-n-1#comment5Thu, 23 Oct 2008 13:27:07 GMTIs the .RawSql '==' operator overridden? If the raw sql is just a string, it would be a lot more useful to compare the actual pieces of the string (and their order) instead of seeing if the two strings are identical. IE: select * from something should be the same as select * from something http://ayende.com/3657/nh-prof-how-to-detect-select-n-1#comment4http://ayende.com/3657/nh-prof-how-to-detect-select-n-1#comment4Thu, 23 Oct 2008 13:25:50 GMTIt's nice! Can you explain why you picked 4 as the threshold? Was it just arbitrary or based on some experience that if you have less than 4 it's not a problem? Cheers http://ayende.com/3657/nh-prof-how-to-detect-select-n-1#comment3http://ayende.com/3657/nh-prof-how-to-detect-select-n-1#comment3Thu, 23 Oct 2008 13:15:04 GMT[ayende.com/.../...SelectN1ProblemInNHibernate.aspx](http://ayende.com/Blog/archive/2006/05/02/CombatingTheSelectN1ProblemInNHibernate.aspx)http://ayende.com/3657/nh-prof-how-to-detect-select-n-1#comment2http://ayende.com/3657/nh-prof-how-to-detect-select-n-1#comment2Thu, 23 Oct 2008 12:58:02 GMTCan you post a good link to the SELECT N + 1 "problem"(?) http://ayende.com/3657/nh-prof-how-to-detect-select-n-1#comment1http://ayende.com/3657/nh-prof-how-to-detect-select-n-1#comment1Thu, 23 Oct 2008 12:40:31 GMT