postgres.git / summary / log / commit / refs

commit    d0e9c0e3199cefb36dc787293f577cd57b984bfe
Author:   Tom Lane <tgl@sss.pgh.pa.us>
Date:     Wed Feb 15 21:40:06 2017 +0000

    Make sure that hash join's bulk-tuple-transfer loops are interruptible.
    
    The loops in ExecHashJoinNewBatch(), ExecHashIncreaseNumBatches(), and
    ExecHashRemoveNextSkewBucket() are all capable of iterating over many
    tuples without ever doing a CHECK_FOR_INTERRUPTS, so that the backend
    might fail to respond to SIGINT or SIGTERM for an unreasonably long time.
    Fix that.  In the case of ExecHashJoinNewBatch(), it seems useful to put
    the added CHECK_FOR_INTERRUPTS into ExecHashJoinGetSavedTuple() rather
    than directly in the loop, because that will also ensure that both
    principal code paths through ExecHashJoinOuterGetTuple() will do a
    CHECK_FOR_INTERRUPTS, which seems like a good idea to avoid surprises.
    
    Back-patch to all supported branches.
    
    Tom Lane and Thomas Munro
    
    Discussion: https://postgr.es/m/6044.1487121720@sss.pgh.pa.us


 src/backend/executor/nodeHash.c     | 6 ++++++
 src/backend/executor/nodeHashjoin.c | 7 +++++++
 2 files changed, 13 insertions(+)

diff --git a/src/backend/executor/nodeHash.c b/src/backend/executor/nodeHash.c
index ea9e88423e0..d1d1716c101 100644
--- a/src/backend/executor/nodeHash.c
+++ b/src/backend/executor/nodeHash.c
@@ -667,6 +667,9 @@ ExecHashIncreaseNumBatches(HashJoinTable hashtable)
 			}
 
 			tuple = nexttuple;
+
+			/* allow this loop to be cancellable */
+			CHECK_FOR_INTERRUPTS();
 		}
 	}
 
@@ -1438,6 +1441,9 @@ ExecHashRemoveNextSkewBucket(HashJoinTable hashtable)
 		}
 
 		hashTuple = nextHashTuple;
+
+		/* allow this loop to be cancellable */
+		CHECK_FOR_INTERRUPTS();
 	}
 
 	/*
diff --git a/src/backend/executor/nodeHashjoin.c b/src/backend/executor/nodeHashjoin.c
index 7eec3f333de..27e60f09f71 100644
--- a/src/backend/executor/nodeHashjoin.c
+++ b/src/backend/executor/nodeHashjoin.c
@@ -911,6 +911,13 @@ ExecHashJoinGetSavedTuple(HashJoinState *hjstate,
 	size_t		nread;
 	MinimalTuple tuple;
 
+	/*
+	 * We check for interrupts here because this is typically taken as an
+	 * alternative code path to an ExecProcNode() call, which would include
+	 * such a check.
+	 */
+	CHECK_FOR_INTERRUPTS();
+
 	/*
 	 * Since both the hash value and the MinimalTuple length word are uint32,
 	 * we can read them both in one BufFileRead() call without any type


[parent: 804aad8ff46c]