Experiment with elimnation of global snapshot

knizhnik · knizhnik · commit 277ab49ab398 · 2016-01-13T19:21:57.000+03:00
diff --git a/contrib/multimaster/multimaster.c b/contrib/multimaster/multimaster.c
@@ -238,7 +238,7 @@ static void DtmMergeWithGlobalSnapshot(Snapshot dst)
 	TransactionId xid;
 	Snapshot src = &DtmSnapshot;
 
-	if (!(TransactionIdIsValid(src->xmin) && TransactionIdIsValid(src->xmax))) { 
+	if (true || !(TransactionIdIsValid(src->xmin) && TransactionIdIsValid(src->xmax))) { 
         PgGetSnapshotData(dst);
         return;
     }
@@ -627,7 +627,7 @@ static Snapshot DtmGetSnapshot(Snapshot snapshot)
 			/* Use single global snapshot during all transaction for repeatable read isolation level,
 			 * but obtain new global snapshot each time it is requested for read committed isolation level
 			 */
-			DtmHasGlobalSnapshot = false;
+			//DtmHasGlobalSnapshot = false;
 		}
 	}
 	else

Original file line number	Diff line number	Diff line change
`@@ -238,7 +238,7 @@ static void DtmMergeWithGlobalSnapshot(Snapshot dst)`
`238`	`238`	`TransactionId xid;`
`239`	`239`	`Snapshot src = &DtmSnapshot;`
`240`	`240`
`241`		`- if (!(TransactionIdIsValid(src->xmin) && TransactionIdIsValid(src->xmax))) {`
	`241`	`+ if (true \|\| !(TransactionIdIsValid(src->xmin) && TransactionIdIsValid(src->xmax))) {`
`242`	`242`	`PgGetSnapshotData(dst);`
`243`	`243`	`return;`
`244`	`244`	`}`
`@@ -627,7 +627,7 @@ static Snapshot DtmGetSnapshot(Snapshot snapshot)`
`627`	`627`	`/* Use single global snapshot during all transaction for repeatable read isolation level,`
`628`	`628`	`* but obtain new global snapshot each time it is requested for read committed isolation level`
`629`	`629`	`*/`
`630`		`- DtmHasGlobalSnapshot = false;`
	`630`	`+ //DtmHasGlobalSnapshot = false;`
`631`	`631`	`}`
`632`	`632`	`}`
`633`	`633`	`else`