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authorTom Lane <tgl@sss.pgh.pa.us>2016-08-07 13:15:55 -0400
committerTom Lane <tgl@sss.pgh.pa.us>2016-08-07 13:15:55 -0400
commit71dca408c0030ad76044c6b17367c9fbeac511ec (patch)
tree8d6c793cf91ee81ade73fce1eb096c112133f849 /src/backend/replication/logical/reorderbuffer.c
parentee5d1de04f3354c7a87219c2ed481ae51a1bb3b8 (diff)
downloadpostgresql-71dca408c0030ad76044c6b17367c9fbeac511ec.tar.gz
postgresql-71dca408c0030ad76044c6b17367c9fbeac511ec.zip
Don't propagate a null subtransaction snapshot up to parent transaction.
This oversight could cause logical decoding to fail to decode an outer transaction containing changes, if a subtransaction had an XID but no actual changes. Per bug #14279 from Marko Tiikkaja. Patch by Marko based on analysis by Andrew Gierth. Discussion: <20160804191757.1430.39011@wrigleys.postgresql.org>
Diffstat (limited to 'src/backend/replication/logical/reorderbuffer.c')
-rw-r--r--src/backend/replication/logical/reorderbuffer.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
index 9b5642a5162..29bbae601c0 100644
--- a/src/backend/replication/logical/reorderbuffer.c
+++ b/src/backend/replication/logical/reorderbuffer.c
@@ -744,13 +744,14 @@ ReorderBufferCommitChild(ReorderBuffer *rb, TransactionId xid,
elog(ERROR, "subxact logged without previous toplevel record");
/*
- * Pass the our base snapshot to the parent transaction if it doesn't have
+ * Pass our base snapshot to the parent transaction if it doesn't have
* one, or ours is older. That can happen if there are no changes in the
* toplevel transaction but in one of the child transactions. This allows
- * the parent to simply use it's base snapshot initially.
+ * the parent to simply use its base snapshot initially.
*/
- if (txn->base_snapshot == NULL ||
- txn->base_snapshot_lsn > subtxn->base_snapshot_lsn)
+ if (subtxn->base_snapshot != NULL &&
+ (txn->base_snapshot == NULL ||
+ txn->base_snapshot_lsn > subtxn->base_snapshot_lsn))
{
txn->base_snapshot = subtxn->base_snapshot;
txn->base_snapshot_lsn = subtxn->base_snapshot_lsn;