allowed different processes to have different addresses for the shmem segment
in quite a long time, but there were still a few places left that used the
old coding convention. Clean them up to reduce confusion and improve the
compiler's ability to detect pointer type mismatches.
Kris Jurka
modules; the first try was not usable in EXEC_BACKEND builds (e.g.,
Windows). Instead, just provide some entry points to increase the
allocation requests during postmaster start, and provide a dedicated
LWLock that can be used to synchronize allocation operations performed
by backends. Per discussion with Marc Munro.
an LWLock instead of a spinlock. This hardly matters on Unix machines
but should improve startup performance on Windows (or any port using
EXEC_BACKEND). Per previous discussion.
to 'Size' (that is, size_t), and install overflow detection checks in it.
This allows us to remove the former arbitrary restrictions on NBuffers
etc. It won't make any difference in a 32-bit machine, but in a 64-bit
machine you could theoretically have terabytes of shared buffers.
(How efficiently we could manage 'em remains to be seen.) Similarly,
num_temp_buffers, work_mem, and maintenance_work_mem can be set above
2Gb on a 64-bit machine. Original patch from Koichi Suzuki, additional
work by moi.
Also performed an initial run through of upgrading our Copyright date to
extend to 2005 ... first run here was very simple ... change everything
where: grep 1996-2004 && the word 'Copyright' ... scanned through the
generated list with 'less' first, and after, to make sure that I only
picked up the right entries ...
to shared memory as soon as possible, ie, right after read_backend_variables.
The effective difference from the original code is that this happens
before instead of after read_nondefault_variables(), which loads GUC
information and is apparently capable of expanding the backend's memory
allocation more than you'd think it should. This should fix the
failure-to-attach-to-shared-memory reports we've been seeing on Windows.
Also clean up a few bits of unnecessarily grotty EXEC_BACKEND code.
shared memory segment ID. If we can't access the existing shmem segment,
it must not be relevant to our data directory. If we can access it,
then attach to it and check for an actual match to the data directory.
This should avoid some cases of failure-to-restart-after-boot without
introducing any significant risk of failing to detect a still-running
old backend.
on 64-bit Solaris. Use a non-system-dependent datatype for UsedShmemSegID,
namely unsigned long (which we were already assuming could hold a shmem
key anyway, cf RecordSharedMemoryInLockFile).
As proof of concept, provide an alternate implementation based on POSIX
semaphores. Also push the SysV shared-memory implementation into a
separate file so that it can be replaced conveniently.
Bruce Momjian
Magnus Hagander
Tom Lane
PostgreSQL Daemon