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Allow maximum number of backends to be set at configure time

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(--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.
This commit is contained in:
Tom Lane
1999-02-19 06:06:39 +00:00
parent 612b8434e4
commit e77b630cf0
14 changed files with 502 additions and 392 deletions
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12
src/backend/storage/ipc/ipci.c
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@@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/storage/ipc/ipci.c,v 1.18 1999/02/13 23:18:11 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/storage/ipc/ipci.c,v 1.19 1999/02/19 06:06:04 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -44,17 +44,19 @@ SystemPortAddressCreateIPCKey(SystemPortAddress address)
CreateSharedMemoryAndSemaphores
is called exactly *ONCE* by the postmaster.
It is *NEVER* called by the postgres backend
It is *NEVER* called by the postgres backend,
except in the case of a standalone backend.
0) destroy any existing semaphores for both buffer
and lock managers.
1) create the appropriate *SHARED* memory segments
for the two resource managers.
2) create shared semaphores as needed.
**************************************************/
void
CreateSharedMemoryAndSemaphores(IPCKey key)
CreateSharedMemoryAndSemaphores(IPCKey key, int maxBackends)
{
int size;
@@ -98,7 +100,7 @@ CreateSharedMemoryAndSemaphores(IPCKey key)
* do process table stuff
* ----------------
*/
InitProcGlobal(key);
InitProcGlobal(key, maxBackends);
on_shmem_exit(ProcFreeAllSemaphores, NULL);
CreateSharedInvalidationState(key);
@@ -120,7 +122,7 @@ AttachSharedMemoryAndSemaphores(IPCKey key)
*/
if (key == PrivateIPCKey)
{
CreateSharedMemoryAndSemaphores(key);
CreateSharedMemoryAndSemaphores(key, 1);
return;
}