v44_drowley_review.patch

diff --git a/src/backend/catalog/partition.c b/src/backend/catalog/partition.c
index 363b12836b..79cda9cecd 100644
--- a/src/backend/catalog/partition.c
+++ b/src/backend/catalog/partition.c
@@ -1673,9 +1673,9 @@ get_matching_partitions(PartitionPruneContext *context,
 	/*
 	 * Allocate space for individual pruning steps to store its result.  Each
 	 * slot will hold a PruneStepResult after performing a given pruning step.
-	 * Later steps may use the result of one or more earlier steps.  Result of
-	 * of applying all pruning steps is the value contained in the slot of the
-	 * last pruning step.
+	 * Later steps may use the result of one or more earlier steps.  The
+	 * result of applying all pruning steps is the value contained in the slot
+	 * of the last pruning step.
 	 */
 	step_results = (PruneStepResult **)
 							palloc0(num_steps * sizeof(PruneStepResult *));
@@ -1705,10 +1705,9 @@ get_matching_partitions(PartitionPruneContext *context,
 	}
 
 	/*
-	 * At this point we know that offsets of all the datums whose
-	 * corresponding partitions need to be in the result, including special
-	 * null-accepting and default partitions.  Collect the actual partition
-	 * indexes now.
+	 * At this point we know the offsets of all the datums whose corresponding
+	 * partitions need to be in the result, including special null-accepting
+	 * and default partitions.  Collect the actual partition indexes now.
 	 */
 	i = -1;
 	result = NULL;
@@ -1819,7 +1818,9 @@ perform_pruning_base_step(PartitionPruneContext *context,
 				if (cmpfn != context->partsupfunc[keyno].fn_oid)
 					fmgr_info(cmpfn, &partsupfunc[keyno]);
 				else
-					partsupfunc[keyno] = context->partsupfunc[keyno];
+					fmgr_info_copy(&partsupfunc[keyno],
+								   &context->partsupfunc[keyno],
+								   CurrentMemoryContext);
 
 				values[keyno] = datum;
 				nvalues++;
@@ -1985,11 +1986,11 @@ perform_pruning_combine_step(PartitionPruneContext *context,
 					source = step_results[source_step_id];
 					Assert(source != NULL);
 
-					/* First add possible datum offsets. */
+					/* First add all possible datum offsets. */
 					result->datum_offsets =
 										bms_add_range(NULL, 0,
 													  boundinfo->ndatums - 1);
-					/* Then remove from it those present in the source. */
+					/* Then remove the members present in source. */
 					result->datum_offsets =
 									bms_del_members(result->datum_offsets,
 													source->datum_offsets);
@@ -2037,7 +2038,7 @@ partkey_datum_from_expr(PartitionPruneContext *context,
  *		Determine offset of the hash bound matching the specified value,
  *		considering that all the non-null values come from clauses containing
  *		a compatible hash eqaulity operator and any keys that are null come
- *		from a IS NULL clause
+ *		from an IS NULL clause
  *
  * In most cases, the result would contain just one bound's offset, although
  * the set may be empty if the corresponding hash partition has not been
@@ -2149,17 +2150,10 @@ get_matching_list_bounds(PartitionPruneContext *context,
 		 * the former doesn't exist.
 		 */
 		if (partition_bound_accepts_nulls(boundinfo))
-		{
 			result->scan_null = true;
-			return result;
-		}
 		else if (partition_bound_has_default(boundinfo))
-		{
 			result->scan_default = true;
-			return result;
-		}
-		else
-			return result;
+		return result;
 	}
 
 	/*
@@ -2335,7 +2329,7 @@ get_matching_range_bounds(PartitionPruneContext *context,
 	result = (PruneStepResult *) palloc0(sizeof(PruneStepResult));
 
 	/*
-	 * If there are no datums to compare keys with, or if we got a IS NULL
+	 * If there are no datums to compare keys with, or if we got an IS NULL
 	 * clause just return the default partition, if it exists.
 	 */
 	if (boundinfo->ndatums == 0 || !bms_is_empty(nullkeys))
@@ -2506,8 +2500,13 @@ get_matching_range_bounds(PartitionPruneContext *context,
 				if (partition_bound_has_default(boundinfo))
 				{
 					for (i = minoff; i <= maxoff; i++)
+					{
 						if (partindices[i] < 0)
+						{
 							result->scan_default = true;
+							break;
+						}
+					}
 				}
 
 				Assert(minoff >= 0 && maxoff >= 0);
@@ -2517,24 +2516,17 @@ get_matching_range_bounds(PartitionPruneContext *context,
 			else if (off >= 0)	/* !is_equal */
 			{
 				/*
-				 * Look-up value falls in the range between some bounds in
-				 * boundinfo.  off would be the offset of the greatest
+				 * The look-up value falls in the range between some bounds in
+				 * boundinfo.  'off' would be the offset of the greatest
 				 * bound that is <= look-up value, so add off + 1 to the
 				 * result instead as the offset of the upper bound of the
 				 * only partition that may contain the look-up value.
 				 */
 				if (partindices[off + 1] >= 0)
-				{
 					result->datum_offsets = bms_make_singleton(off + 1);
-					return result;
-				}
 				else if (partition_bound_has_default(boundinfo))
-				{
 					result->scan_default = true;
-					return result;
-				}
-				else
-					return result;
+				return result;
 			}
 			/*
 			 * off < 0, meaning the look-up value is smaller that all bounds,
@@ -2683,8 +2675,8 @@ get_matching_range_bounds(PartitionPruneContext *context,
 					maxoff = inclusive ? off + 1: off;
 				}
 				/*
-				 * Look-up value falls in the range between some bounds in
-				 * boundinfo.  off would be the offset of the greatest
+				 * The look-up value falls in the range between some bounds in
+				 * boundinfo.  'off' would be the offset of the greatest
 				 * bound that is <= look-up value, so add off + 1 to the
 				 * result instead as the offset of the upper bound of the
 				 * greatest partition that may contain look-up value.  If
diff --git a/src/backend/optimizer/util/partprune.c b/src/backend/optimizer/util/partprune.c
index 48fdeacac3..2dd4a3ecf3 100644
--- a/src/backend/optimizer/util/partprune.c
+++ b/src/backend/optimizer/util/partprune.c
@@ -254,7 +254,7 @@ generate_partition_pruning_steps(RelOptInfo *rel, List *clauses,
  * If when going through clauses, we find any that are marked as pseudoconstant
  * and contains a constant false value, we stop generating any further steps
  * and simply return NIL (that is, no pruning steps) after setting *constfalse
- * to true.  Caller should consider all partitions as pruned in that case.
+ * to true.  The caller should consider all partitions as pruned in that case.
  * We may do the same if we find that mutually contradictory clauses are
  * present, but were not turned into a pseudoconstant at higher levels.
  *
@@ -593,7 +593,7 @@ generate_partition_pruning_steps_internal(RelOptInfo *rel,
 		unionStep = (PartitionPruneStep *)
 						generate_pruning_step_combine(context, step_ids,
 													  COMBINE_UNION);
-		/* Then slap on a DIFFERENCE combine step. */
+		/* Now add a step to invert the results. */
 		diffStep = (PartitionPruneStep *)
 					generate_pruning_step_combine(context,
 										  list_make1_int(unionStep->step_id),
@@ -603,7 +603,7 @@ generate_partition_pruning_steps_internal(RelOptInfo *rel,
 	}
 
 	/*
-	 * generate_opsteps set to false means no OpExprs were directly presemt in
+	 * generate_opsteps set to false means no OpExprs were directly present in
 	 * the input list.
 	 */
 	if (!generate_opsteps)
@@ -802,8 +802,8 @@ generate_pruning_steps_from_opexprs(PartitionScheme part_scheme,
 		}
 
 		/*
-		 * If we've decided that clauses for subsequent partition keys would't
-		 * be useful for pruning, don't look.
+		 * If we've decided that clauses for subsequent partition keys
+		 * wouldn't be useful for pruning, don't look.
 		 */
 		if (!consider_next_key)
 			break;