Various places were supposing that errno could be expected to hold still
within an ereport() nest or similar contexts. This isn't true necessarily,
though in some cases it accidentally failed to fail depending on how the
compiler chanced to order the subexpressions. This class of thinko
explains recent reports of odd failures on clang-built versions, typically
missing or inappropriate HINT fields in messages.
Problem identified by Christian Kruse, who also submitted the patch this
commit is based on. (I fixed a few issues in his patch and found a couple
of additional places with the same disease.)
Back-patch as appropriate to all supported branches.
The exclusion of SIGALRM dates back to Berkeley days, when Postgres used
SIGALRM in only one very short stretch of code. Nowadays, allowing it to
interrupt kernel calls doesn't seem like a very good idea, since its use
for statement_timeout means SIGALRM could occur anyplace in the code, and
there are far too many call sites where we aren't prepared to deal with
EINTR failures. When third-party code is taken into consideration, it
seems impossible that we ever could be fully EINTR-proof, so better to
use SA_RESTART always and deal with the implications of that. One such
implication is that we should not assume pg_usleep() will be terminated
early by a signal. Therefore, long sleeps should probably be replaced
by WaitLatch operations where practical.
Back-patch to 9.3 so we can get some beta testing on this change.
Also, we removed the display of the current value of
max_connections/MaxBackends from some messages earlier, because it was
confusing, so do that in the remaining one as well.
whether to execute an immediate interrupt, rather than testing whether
LockWaitCancel() cancelled a lock wait. The old way misclassified the case
where we were blocked in ProcWaitForSignal(), and arguably would misclassify
any other future additions of new ImmediateInterruptOK states too. This
allows reverting the old kluge that gave LockWaitCancel() a return value,
since no callers care anymore. Improve comments in the various
implementations of PGSemaphoreLock() to explain that on some platforms, the
assumption that semop() exits after a signal is wrong, and so we must ensure
that the signal handler itself throws elog if we want cancel or die interrupts
to be effective. Per testing related to bug #3883, though this patch doesn't
solve those problems fully.
Perhaps this change should be back-patched, but since pre-8.3 branches aren't
really relying on autovacuum to respond to SIGINT, it doesn't seem critical
for them.
comment line where output as too long, and update typedefs for /lib
directory. Also fix case where identifiers were used as variable names
in the backend, but as typedefs in ecpg (favor the backend for
indenting).
Backpatch to 8.1.X.
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 ...
Natoli and Bruce Momjian (and some cosmetic fixes from Neil Conway).
Changes:
- remove duplicate signal definitions from pqsignal.h
- replace pqkill() with kill() and redefine kill() in Win32
- use ereport() in place of fprintf() in some error handling in
pqsignal.c
- export pg_queue_signal() and make use of it where necessary
- add a console control handler for Ctrl-C and similar handling
on Win32
- do WaitForSingleObjectEx() in CHECK_FOR_INTERRUPTS() on Win32;
query cancelling should now work on Win32
- various other fixes and cleanups
against the latest shapshot. It also includes the replacement of kill()
with pqkill() and sigsetmask() with pqsigsetmask().
Passes all tests fine on my linux machine once applied. Still doesn't
link completely on Win32 - there are a few things still required. But
much closer than before.
At Bruce's request, I'm goint to write up a README file about the method
of signals delivery chosen and why the others were rejected (basically a
summary of the mailinglist discussions). I'll finish that up once/if the
patch is accepted.
Magnus Hagander
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.
Tom Lane
Bruce Momjian
Peter Eisentraut
Magnus Hagander
PostgreSQL Daemon
Neil Conway