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RE: back-bdb deadlocks
> -----Original Message-----
> From: Kurt D. Zeilenga [mailto:Kurt@OpenLDAP.org]
> Even that's pretty slow. I see on my old FreeBSD devbox (2*P350)
> with userland threads (one execution context). For -008:
> 1.323u 1.586s 1:18.83 3.6% 222+3232k 68+265io 148pf+0w
> Have you updated glibc/pthreads, did you completely rebuild bdb?
> I wonder if NGpthreads for Linux (from IBM) would help.
I've updated to glibc 2.2.4/linuxthreads 0.9, did not rebuild bdb after that.
Your db_stat results are interesting, 0 deadlocks. I can now get this
sometimes, but other times there are a few. I would expect this to be totally
non-deterministic. Must have something to do with thread scheduling
algorithms... With usermode threads you also need aio support, otherwise
any blocking I/O blocks all threads, making you effectively single-threaded.
That would certainly give deadlock-free execution.
> 1/2743070 File/offset for last checkpoint LSN.
> 0/0 No pending checkpoint LSN.
> Thu Jan 17 21:01:23 2002 Checkpoint timestamp.
> 80000136 Last transaction ID allocated.
> 20 Maximum number of active transactions possible.
> 0 Active transactions.
> 3 Maximum active transactions.
> 310 Number of transactions begun.
> 5 Number of transactions aborted.
> 305 Number of transactions committed.
> 0 Number of transactions restored.
> 16KB Transaction region size (16384 bytes).
> 0 The number of region locks granted after waiting.
> 637 The number of region locks granted without waiting.
> 73 Last allocated locker ID.
> 9 Number of lock modes.
> 1000 Maximum number of locks possible.
> 1000 Maximum number of lockers possible.
> 1000 Maximum number of objects possible.
> 150846 Current locks.
> 150864 Maximum number of locks so far.
> 0 Current number of lockers.
> 22 Maximum number lockers so far.
> 0 Current number lock objects.
> 16 Maximum number of lock objects so far.
> 178824 Number of lock requests.
> 178824 Number of lock releases.
> 0 Number of lock requests that would have waited.
> 699 Number of lock conflicts.
> 0 Number of deadlocks.
> 0 Number of transaction timeouts.
> 0 Number of lock timeouts.
> 352KB Lock region size (360448 bytes).
> 19 The number of region locks granted after waiting.
> 199355 The number of region locks granted without waiting.
-- Howard Chu
Chief Architect, Symas Corp. Director, Highland Sun
Symas: Premier OpenSource Development and Support