Manuj Bhatia wrote:
> I do not have a requirement of persistence in my current design, but I
> expect that we might extend this shared-queue solution to more areas of
> the server and will require some sort of persistence then.
> That is one of the main reasons I do not want to use IPC queues (there are
> other reasons like fixed message sizes, minimal support for queue/message
> level metadata).
OP might consider creating a database file on a tmpfs filesystem.
The OS tricks SQLite (and everything in user space) into thinking the
file is a normal file with all the usual properties thereof -- but
it's backed by RAM and not any persistent medium. You'll get the perf
benefits you wanted, along with the relatively easy ability to make the
DB persistent later.
Fedora 12 has one of these mounted at /dev/shm by default, though I
presume any modern Linux will support this.
Caveat (1). I ran 'make test' on SQLite 3.6.23.1 on my box (Linux ___
2.6.32.11-99.fc12.i686 #1 SMP Mon Apr 5 16:32:08 EDT 2010 i686 athlon
i386 GNU/Linux) from within a tmpfs filesystem and 23 tests failed:
shared-1.1.1 shared-1.2.1 shared-1.4.1.1 shared-1.4.1.2 shared-1.4.1.3
shared-2.1.1 shared-2.2.1 shared-2.4.1.1 shared-2.4.1.2 shared-2.4.1.3
stmt-1.2 stmt-1.3 stmt-1.4 stmt-1.5 stmt-1.6 stmt-1.7 stmt-2.1 stmt-2.2
stmt-2.3 stmt-2.5 tempdb-2.2 tempdb-2.3 tkt2565-1.X
I wanted to investigate to see why but haven't had the time -- it has
to do with the global Tcl variable sqlite_open_file_count. Running the
fixture on just those test files yields passes (every time), but running
the whole 'veryquick' suite yields failures (every time). I see there's
machinery to try to clear all state between test runs -- obviously this
is not successful in my test.
The testfixture is dynamically linked against these libraries:
linux-gate.so.1 => (0x00511000)
libtcl8.5.so => /usr/lib/libtcl8.5.so (0x005cb000)
libdl.so.2 => /lib/libdl.so.2 (0x00d1f000)
libm.so.6 => /lib/libm.so.6 (0x00d42000)
libpthread.so.0 => /lib/libpthread.so.0 (0x00d26000)
libc.so.6 => /lib/libc.so.6 (0x00ba9000)
/lib/ld-linux.so.2 (0x00b87000)
Caveat (2). I don't claim this is the best solution for the OP -- just
a possibility.
Eric
--
Eric A. Smith
I think there's a world market for about five computers.
-- attr. Thomas J. Watson (Chairman of the Board, IBM), 1943
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