expired messages before concluding that we really have buffer overflow.

offended my aesthestic sensibility that there was so much unreadable code
doing so little.  Rewritten code is about half the size, faster, and
(I hope) much more intelligible.

the SInval spinlock while it is calling the passed invalFunction or
resetFunction.  This is necessary to avoid deadlock with lmgr change;
InvalidateSharedInvalid can be called recursively now.  It should be
a good performance improvement anyway --- holding a spinlock for more
than a very short interval is a no-no.

through MAXBACKENDS array entries used to be fine when MAXBACKENDS = 64.
It's not so cool with MAXBACKENDS = 1024 (or more!), especially not in a
frequently-used routine like SIDelExpiredDataEntries.  Repair by making
procState array size be the soft MaxBackends limit rather than the hard
limit, and by converting SIGetProcStateLimit() to a macro.

real affect now.

(--with-maxbackends).  Add a postmaster switch (-N backends) that allows
the limit to be reduced at postmaster start time.  (You can't increase it,
sorry to say, because there are still some fixed-size arrays.)
Grab the number of semaphores indicated by min(MAXBACKENDS, -N) at
postmaster startup, so that this particular form of bogus configuration
is exposed immediately rather than under heavy load.

From: Massimo Dal Zotto <dz@cs.unitn.it>

> sinval.patch
>
>       fixes a problem in SI cache which causes table overflow if some
>       backend is idle for a long time while other backends keep adding
>       entries.
>       It uses the new signal handling implemented in tprintf.patch.
>       I have also increacasesed the max number of backends from 32 to 64
>       and the table size from 1000 to 5000.
>       I don't know if anybody is working on SI, but until another
>       solution is found this patch fixes the problem. I have received
>       messages from other people reporting the same problem which I
>       fixed many months ago.

shmem_exit to replace exitpg().

Another PGINDENT run that changes variable indenting and case label indenting.  Also static variable indenting.

Various compile errors concerning overflow due to shifts, unsigned, and bad prototypes, from Solaris, from Diab Jerius

Add #include "postgres.h" as required

Remove #include "c.h" *and* "utils/elog.h" as applicable