Hi,
I had a problem with one of my AOLServers (4.0.10): under heavy
load all threads associated with one of the virtual servers sometimes
disappear. I have changed "connsperthread" connection pool parameter to 0
and now all seems to work. I've examined source code and found the
following (possible?) scenario:
There are two threads, one for driver and one running connection.
Moreover, the pool parameter "connsperthread" is set to 1 (so, every
thread exits after running a connection).
1) In function NsConnThread (file "queue.c") thread finishes running
connection. Then it set poolPtr->threads.idle=1 and unlock mutex
&servPtr->pools.lock calling NsRunAtReadyProcs.
2) Now a new connection arrives. In function NsQueueConn (file "queue.c")
driver thread checks that poolPtr.threads.idle==1, so it does not create
any new thread. The connection is queued.
3) Thread from the point (1) exits without serving new connection, since
it has "ncons" set to 1. It decrement poolPtr.threads.idle to 0.
4) Now there is one queued connection, poolPtr.threads.idle==0, and
there is no thread to run queued connection.
Is it possible?
Best regards,
Piotr Szuca
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