1. Vacuum is updated for MVCC.

2. Much faster btree tuples deletion in the case when first on page
   index tuple is deleted (no movement to the left page(s)).
3. Remember blkno of new root page in BTPageOpaque of
   left/right siblings when root page is splitted.

1 files changed, 60 insertions, 13 deletions

diff --git a/src/backend/storage/ipc/shmem.c b/src/backend/storage/ipc/shmem.c
index 3653e844ab6..55ecd857970 100644
--- a/src/backend/storage/ipc/shmem.c
+++ b/src/backend/storage/ipc/shmem.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/storage/ipc/shmem.c,v 1.37 1999/02/22 06:16:48 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/storage/ipc/shmem.c,v 1.38 1999/03/28 20:32:22 vadim Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -636,12 +636,13 @@ TransactionIdIsInProgress(TransactionId xid)
 Snapshot
 GetSnapshotData(bool serializable)
 {
-	Snapshot	snapshot = (Snapshot) malloc(sizeof(SnapshotData));
-	ShmemIndexEnt *result;
-	PROC	   *proc;
-	TransactionId cid = GetCurrentTransactionId();
-	uint32		count = 0;
-	uint32		have = 32;
+	Snapshot		snapshot = (Snapshot) malloc(sizeof(SnapshotData));
+	ShmemIndexEnt  *result;
+	PROC		   *proc;
+	TransactionId	cid = GetCurrentTransactionId();
+	TransactionId	xid;
+	uint32			count = 0;
+	uint32			have = 32;
 
 	Assert(ShmemIndex);
 
@@ -669,19 +670,20 @@ GetSnapshotData(bool serializable)
 			strncmp(result->key, "PID ", 4) != 0)
 			continue;
 		proc = (PROC *) MAKE_PTR(result->location);
-		if (proc == MyProc || proc->xid < FirstTransactionId)
+		xid = proc->xid;	/* we don't use spin-locking in xact.c ! */
+		if (proc == MyProc || xid < FirstTransactionId)
 			continue;
-		if (proc->xid < snapshot->xmin)
-			snapshot->xmin = proc->xid;
-		else if (proc->xid > snapshot->xmax)
-			snapshot->xmax = proc->xid;
+		if (xid < snapshot->xmin)
+			snapshot->xmin = xid;
+		else if (xid > snapshot->xmax)
+			snapshot->xmax = xid;
 		if (have == 0)
 		{
 			snapshot->xip = (TransactionId *) realloc(snapshot->xip,
 								   (count + 32) * sizeof(TransactionId));
 			have = 32;
 		}
-		snapshot->xip[count] = proc->xid;
+		snapshot->xip[count] = xid;
 		have--;
 		count++;
 	}
@@ -692,3 +694,48 @@ GetSnapshotData(bool serializable)
 	elog(ERROR, "GetSnapshotData: ShmemIndex corrupted");
 	return NULL;
 }
+
+/*
+ * GetXmaxRecent -- returns oldest transaction that was running
+ * 					when all current transaction was started.
+ * 					It's used by vacuum to decide what deleted
+ * 					tuples must be preserved in a table.
+ *
+ * And yet another strange func for this place...	- vadim 03/18/99
+ */
+void
+GetXmaxRecent(TransactionId *XmaxRecent)
+{
+	ShmemIndexEnt  *result;
+	PROC		   *proc;
+	TransactionId	xmin;
+
+	Assert(ShmemIndex);
+
+	ReadNewTransactionId(XmaxRecent);
+
+	SpinAcquire(ShmemIndexLock);
+
+	hash_seq((HTAB *) NULL);
+	while ((result = (ShmemIndexEnt *) hash_seq(ShmemIndex)) != NULL)
+	{
+		if (result == (ShmemIndexEnt *) TRUE)
+		{
+			SpinRelease(ShmemIndexLock);
+			return;
+		}
+		if (result->location == INVALID_OFFSET ||
+			strncmp(result->key, "PID ", 4) != 0)
+			continue;
+		proc = (PROC *) MAKE_PTR(result->location);
+		xmin = proc->xmin;	/* we don't use spin-locking in xact.c ! */
+		if (proc == MyProc || xmin < FirstTransactionId)
+			continue;
+		if (xmin < *XmaxRecent)
+			*XmaxRecent = xmin;
+	}
+
+	SpinRelease(ShmemIndexLock);
+	elog(ERROR, "GetXmaxRecent: ShmemIndex corrupted");
+	return NULL;
+}