postgres.git / summary / log / commit / refs

commit    354dfa235b4dfb01e23cee6ad8ec5fe6904004fc
Author:   Tom Lane <tgl@sss.pgh.pa.us>
Date:     Wed Feb 15 21:40:05 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 6375d9bfda7..ebfe9278b6a 100644
--- a/src/backend/executor/nodeHash.c
+++ b/src/backend/executor/nodeHash.c
@@ -720,6 +720,9 @@ ExecHashIncreaseNumBatches(HashJoinTable hashtable)
 
 			/* next tuple in this chunk */
 			idx += MAXALIGN(hashTupleSize);
+
+			/* allow this loop to be cancellable */
+			CHECK_FOR_INTERRUPTS();
 		}
 
 		/* we're done with this chunk - free it and proceed to the next one */
@@ -1599,6 +1602,9 @@ 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 369e666f885..c4d4c600312 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: a3f4c8e50e8e]