Out of semaphores error, continued

[SteveT]

I've seen that other folks have posted on the "Out of semaphores"
problem (cf., http://groups.google.com/group/mongodb-user/msg/61a1bc57dd5a579c);
my question is a little different.

What's weird is that we're doing performance testing right now, and
when I run an identical test against MongoDB hosted on Win64 and
MongoDB hosted on Red Hat Enterprise Linux 6 (64-bit), we're seeing a
big difference in the frequency of this error. There are just a
handful of occurrences over a large number of transactions for Win64,
but many, many more "out of semaphores" issues reported on RHEL. Does
anyone know why that might be?

If it makes a difference, both server systems are hosted in VMWare's
VSphere, and MongoDB is accessed through an HTTP service we have
implemented on top of Apache Tomcat 7.

I'll make some adjustments to MongoOptions for Linux and try again,
but I thought someone here might have insight into the platform-
related differences.

Thanks,

Steve

[Randolph Tan]

Out of Semaphores exception is thrown whenever you try to get a connection from an empty pool. The Java driver keeps a separate pool for each host it connects to. The discrepancy between Windows and RHEL might have to do with the subtle difference on how threads are being scheduled.