Mark correctly initial slot snapshots with MVCC type when built

michaelpq · michaelpq · commit 2ad57e9e9faf · 2019-02-20T12:32:23.000+09:00
When building an initial slot snapshot, snapshots are marked with historic MVCC snapshots as type with the marker field being set in SnapBuildBuildSnapshot() but not overriden in SnapBuildExportSnapshot(). Existing callers of SnapBuildBuildSnapshot() do not care about the type of snapshot used, but extensions calling it actually may, as reported. Author: Antonin Houska Reviewed-by: Álvaro Herrera, Michael Paquier Discussion: https://postgr.es/m/23215.1527665193@localhost Backpatch-through: 9.4
diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c
@@ -636,6 +636,8 @@ SnapBuildExportSnapshot(SnapBuild *builder)
 		TransactionIdAdvance(xid);
 	}
 
+	/* adjust remaining snapshot fields as needed */
+	snap->satisfies = HeapTupleSatisfiesMVCC;
 	snap->xcnt = newxcnt;
 	snap->xip = newxip;
 

Original file line number	Diff line number	Diff line change
`@@ -636,6 +636,8 @@ SnapBuildExportSnapshot(SnapBuild *builder)`
`636`	`636`	`TransactionIdAdvance(xid);`
`637`	`637`	`}`
`638`	`638`
	`639`	`+ /* adjust remaining snapshot fields as needed */`
	`640`	`+ snap->satisfies = HeapTupleSatisfiesMVCC;`
`639`	`641`	`snap->xcnt = newxcnt;`
`640`	`642`	`snap->xip = newxip;`
`641`	`643`