From c2891b46a4b04b80e1fe28ad0bfd75b40e97ea3e Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Tue, 1 Nov 2011 22:44:54 -0400
Subject: [PATCH] Initialize myProcLocks queues just once, at postmaster
startup.
In assert-enabled builds, we assert during the shutdown sequence that
the queues have been properly emptied, and during process startup that
we are inheriting empty queues. In non-assert enabled builds, we just
save a few cycles.
---
src/backend/storage/lmgr/proc.c | 52 ++++++++++++++++++++++++++-------
1 file changed, 41 insertions(+), 11 deletions(-)
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 22cb0b82837..eda3a98a85b 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -157,7 +157,8 @@ void
InitProcGlobal(void)
{
PGPROC *procs;
- int i;
+ int i,
+ j;
bool found;
uint32 TotalProcs = MaxBackends + NUM_AUXILIARY_PROCS;
@@ -222,6 +223,10 @@ InitProcGlobal(void)
procs[i].links.next = (SHM_QUEUE *) ProcGlobal->autovacFreeProcs;
ProcGlobal->autovacFreeProcs = &procs[i];
}
+
+ /* Initialize myProcLocks[] shared memory queues. */
+ for (j = 0; j < NUM_LOCK_PARTITIONS; j++)
+ SHMQueueInit(&(procs[i].myProcLocks[j]));
}
/*
@@ -243,7 +248,6 @@ InitProcess(void)
{
/* use volatile pointer to prevent code rearrangement */
volatile PROC_HDR *procglobal = ProcGlobal;
- int i;
/*
* ProcGlobal should be set up already (if we are a backend, we inherit
@@ -303,8 +307,8 @@ InitProcess(void)
MarkPostmasterChildActive();
/*
- * Initialize all fields of MyProc, except for the semaphore and latch,
- * which were prepared for us by InitProcGlobal.
+ * Initialize all fields of MyProc, except for those previously initialized
+ * by InitProcGlobal.
*/
SHMQueueElemInit(&(MyProc->links));
MyProc->waitStatus = STATUS_OK;
@@ -326,8 +330,16 @@ InitProcess(void)
MyProc->lwWaitLink = NULL;
MyProc->waitLock = NULL;
MyProc->waitProcLock = NULL;
- for (i = 0; i < NUM_LOCK_PARTITIONS; i++)
- SHMQueueInit(&(MyProc->myProcLocks[i]));
+#ifdef USE_ASSERT_CHECKING
+ if (assert_enabled)
+ {
+ int i;
+
+ /* Last process should have released all locks. */
+ for (i = 0; i < NUM_LOCK_PARTITIONS; i++)
+ Assert(SHMQueueEmpty(&(MyProc->myProcLocks[i])));
+ }
+#endif
MyProc->recoveryConflictPending = false;
/* Initialize fields for sync rep */
@@ -408,7 +420,6 @@ InitAuxiliaryProcess(void)
{
PGPROC *auxproc;
int proctype;
- int i;
/*
* ProcGlobal should be set up already (if we are a backend, we inherit
@@ -455,8 +466,8 @@ InitAuxiliaryProcess(void)
SpinLockRelease(ProcStructLock);
/*
- * Initialize all fields of MyProc, except for the semaphore and latch,
- * which were prepared for us by InitProcGlobal.
+ * Initialize all fields of MyProc, except for those previously initialized
+ * by InitProcGlobal.
*/
SHMQueueElemInit(&(MyProc->links));
MyProc->waitStatus = STATUS_OK;
@@ -473,8 +484,16 @@ InitAuxiliaryProcess(void)
MyProc->lwWaitLink = NULL;
MyProc->waitLock = NULL;
MyProc->waitProcLock = NULL;
- for (i = 0; i < NUM_LOCK_PARTITIONS; i++)
- SHMQueueInit(&(MyProc->myProcLocks[i]));
+#ifdef USE_ASSERT_CHECKING
+ if (assert_enabled)
+ {
+ int i;
+
+ /* Last process should have released all locks. */
+ for (i = 0; i < NUM_LOCK_PARTITIONS; i++)
+ Assert(SHMQueueEmpty(&(MyProc->myProcLocks[i])));
+ }
+#endif
/*
* Acquire ownership of the PGPROC's latch, so that we can use WaitLatch.
@@ -687,6 +706,17 @@ ProcKill(int code, Datum arg)
/* Make sure we're out of the sync rep lists */
SyncRepCleanupAtProcExit();
+#ifdef USE_ASSERT_CHECKING
+ if (assert_enabled)
+ {
+ int i;
+
+ /* Last process should have released all locks. */
+ for (i = 0; i < NUM_LOCK_PARTITIONS; i++)
+ Assert(SHMQueueEmpty(&(MyProc->myProcLocks[i])));
+ }
+#endif
+
/*
* Release any LW locks I am holding. There really shouldn't be any, but
* it's cheap to check again before we cut the knees off the LWLock
--
GitLab