postgres.git / summary / log / commit / refs

commit    3838074f864eda344677fba39c6141ccbcd4104b
Author:   Robert Haas <rhaas@postgresql.org>
Date:     Wed Jan 25 02:53:38 2017 +0000

    Be more aggressive in avoiding tuple conversion.
    
    According to the comments in tupconvert.c, it's necessary to perform
    tuple conversion when either table has OIDs, and this was previously
    checked by ensuring that the tdtypeid value matched between the tables
    in question.  However, that's overly stringent: we have access to
    tdhasoid and can test directly whether OIDs are present, which lets us
    avoid conversion in cases where the type OIDs are different but the
    tuple descriptors are entirely the same (and neither has OIDs).  This
    is useful to the partitioning code, which can thereby avoid converting
    tuples when inserting into a partition whose columns appear in the
    same order as the parent columns, the normal case.  It's possible
    for the tuple routing code to avoid some additional overhead in this
    case as well, so do that, too.
    
    It's not clear whether it would be OK to skip this when both tables
    have OIDs: do callers count on this to build a new tuple (losing the
    previous OID) in such instances?  Until we figure it out, leave the
    behavior in that case alone.
    
    Amit Langote, reviewed by me.


 src/backend/access/common/tupconvert.c | 18 ++++++++++--------
 src/backend/catalog/partition.c        |  3 +--
 2 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/src/backend/access/common/tupconvert.c b/src/backend/access/common/tupconvert.c
index b17ceafa6ef..a4012525d80 100644
--- a/src/backend/access/common/tupconvert.c
+++ b/src/backend/access/common/tupconvert.c
@@ -138,12 +138,13 @@ convert_tuples_by_position(TupleDesc indesc,
 						   nincols, noutcols)));
 
 	/*
-	 * Check to see if the map is one-to-one and the tuple types are the same.
-	 * (We check the latter because if they're not, we want to do conversion
-	 * to inject the right OID into the tuple datum.)
+	 * Check to see if the map is one-to-one, in which case we need not do
+	 * the tuple conversion.  That's not enough though if either source or
+	 * destination (tuples) contains OIDs; we'd need conversion in that case
+	 * to inject the right OID into the tuple datum.
 	 */
 	if (indesc->natts == outdesc->natts &&
-		indesc->tdtypeid == outdesc->tdtypeid)
+		!indesc->tdhasoid && !outdesc->tdhasoid)
 	{
 		for (i = 0; i < n; i++)
 		{
@@ -214,12 +215,13 @@ convert_tuples_by_name(TupleDesc indesc,
 	attrMap = convert_tuples_by_name_map(indesc, outdesc, msg);
 
 	/*
-	 * Check to see if the map is one-to-one and the tuple types are the same.
-	 * (We check the latter because if they're not, we want to do conversion
-	 * to inject the right OID into the tuple datum.)
+	 * Check to see if the map is one-to-one, in which case we need not do
+	 * the tuple conversion.  That's not enough though if either source or
+	 * destination (tuples) contains OIDs; we'd need conversion in that case
+	 * to inject the right OID into the tuple datum.
 	 */
 	if (indesc->natts == outdesc->natts &&
-		indesc->tdtypeid == outdesc->tdtypeid)
+		!indesc->tdhasoid && !outdesc->tdhasoid)
 	{
 		same = true;
 		for (i = 0; i < n; i++)
diff --git a/src/backend/catalog/partition.c b/src/backend/catalog/partition.c
index 7be60529c53..4bcef587637 100644
--- a/src/backend/catalog/partition.c
+++ b/src/backend/catalog/partition.c
@@ -1700,12 +1700,11 @@ get_partition_for_tuple(PartitionDispatch *pd,
 			return -1;
 		}
 
-		if (myslot != NULL)
+		if (myslot != NULL && map != NULL)
 		{
 			HeapTuple	tuple = ExecFetchSlotTuple(slot);
 
 			ExecClearTuple(myslot);
-			Assert(map != NULL);
 			tuple = do_convert_tuple(tuple, map);
 			ExecStoreTuple(tuple, myslot, InvalidBuffer, true);
 			slot = myslot;


[parent: 7fa7bf18e493]