>>>>> "Tom" == Tom Lane <[EMAIL PROTECTED]> writes:
Tom> Sailesh Krishnamurthy <[EMAIL PROTECTED]> writes: >> We implemented a Shared Memory MemoryContext using OSSP libmm >> (used in Apache) for TelegraphCQ. Tom> How portable is that? What kind of real-world performance do Tom> you get? As portable as libmm I guess. We've only tried it on Linux and MacOS X. I understand that the Apache guys use it - so it should be fairly portable. http://www.ossp.org/pkg/lib/mm/ Actually I've also tried it successfully on SPARC Solaris. I believe that a user of our first TelegraphCQ release (that we did not announce) tried it on FreeBSD. Sean Chittenden has tried it on FreeBSD but I'm not sure if he built it and got it to work properly. As for our SHMemoryContext code itself, it's pretty much a straight copy of the code in aset.c and mctx.c, with appropriate changes where we call the mm_alloc functions and also use mm_lock and mm_unlock for protection. As for performance, I'm in the midst of a performance study, but it's not a micro-benchmark of the shmem allocator. After I get some numbers I'll start profiling our code. One problem is that on some platforms the locking implementation uses the file-system. This is not in our control and we just trust mm to do the best possible. Given that we rely on shared query execution (we run multiple queries in a single adaptive query plan) we don't have much choice - we must rely on shared memory. -- Pip-pip Sailesh http://www.cs.berkeley.edu/~sailesh ---------------------------(end of broadcast)--------------------------- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])