Thursday, July 11, 2002

.NET CLR Large Heap Allocation Bug I got bit by this nasty one today!  We have a web service that we use to update items in our database.  One of our developers was working on attaching images to records and got nailed with this bug. He was sending a 5 MB attachment in the dataset as a blob.  At first the Web Service wouldn't even accept the request.  We realized we needed to increase MaxRequestLength in the machine.config beyond the default of 4096KB to allow the Web Service to get the request.  When we did we found the aspnet_wp.exe process would ballon to over 300MB at which point it would hit the 60% process model limit and restart the worker process! We decided to run some tests and created a web service that looked like this: [WebMethod] public string Test(string strData) { return strData; } We then called this Web Service with a client that varied the strData sent in from 1MB to 10MB.  We found the following: Payload Size Bytes Managed Bytes Mem Usage Kilobytes Managed Change Mem Usage Change   2510430 24,696     1048576 19287617 43732 16777187 19,036 2097152 16410643 67172 -2876974 23,440 3145728 20203539 82116 3792896 14,944 4194304 31475731 121240 11272192 39,124 5242880 35641363 137432 4165632 16,192 6291456 39708691 137584 4067328 152 7340032 13158791 172476 -26549900 34,892 8388608   Recycled the aspnet_wp.exe process       From what we can tell on average for every 1MB of extra data we threw at the Web Service aspnet_wp.exe chewed up an extra 15-20MB of memory.  On a 512MB machine this meant we could process a 7MB request max before restarting the worker process.  Note this is with only 1 request hitting the machine.  In production this would be deadly. Asking around I was told this is part of the large object heap memory allocation bug that exists in version 1.0 of the CLR.  This bug is further documented here: Whoa - GC incorrectly handles large freed objects 4:46:47 PM

Content Management Server Microsoft finally figured out how to solve their pricing issues with Content Management Server.  It was originally priced at around $40K per processor.  CMS 2002 is now priced at: Pricing varies based on deployment scenario. IOW they took so much crap for their previously insane pricing they aren't even going to publish it this time around.  You have to call them to figure out if you can afford the software.  Come on guys.  I think this is definitely a place where there is a big need in corporate america but you have to price it down into the realm where it doesn't take a major budgetary line item just to get it purchased and installed.  Start thinking down in the couple of thousand dollar range where you price Win2K Server et. all. 4:27:05 PM