diff --git a/src/backend/utils/mmgr/README b/src/backend/utils/mmgr/README
index 45e610d..e01bcd4 100644
*** a/src/backend/utils/mmgr/README
--- b/src/backend/utils/mmgr/README
*************** lifetimes that only partially overlap ca
*** 125,133 ****
  from different trees of the context forest (there are some examples
  in the next section).
  
! For convenience we will also want operations like "reset/delete all
! children of a given context, but don't reset or delete that context
! itself".
  
  
  Globally Known Contexts
--- 125,137 ----
  from different trees of the context forest (there are some examples
  in the next section).
  
! Actually, it turns out that resetting a given context should almost
! always imply deleting (not just resetting) any child contexts it has.
! So MemoryContextReset() means that, and if you really do want a forest of
! empty contexts you need to call MemoryContextResetButPreserveChildren().
! 
! For convenience we also provide operations like "reset/delete all children
! of a given context, but don't reset or delete that context itself".
  
  
  Globally Known Contexts
diff --git a/src/backend/utils/mmgr/mcxt.c b/src/backend/utils/mmgr/mcxt.c
index 202bc78..f40c33e 100644
*** a/src/backend/utils/mmgr/mcxt.c
--- b/src/backend/utils/mmgr/mcxt.c
*************** MemoryContextInit(void)
*** 132,145 ****
  
  /*
   * MemoryContextReset
   *		Release all space allocated within a context and its descendants,
   *		but don't delete the contexts themselves.
   *
   * The type-specific reset routine handles the context itself, but we
   * have to do the recursion for the children.
   */
  void
! MemoryContextReset(MemoryContext context)
  {
  	AssertArg(MemoryContextIsValid(context));
  
--- 132,176 ----
  
  /*
   * MemoryContextReset
+  *		Release all space allocated within a context and delete all its
+  *		descendant contexts (but not the named context itself).
+  *
+  * The type-specific reset routine handles the context itself, but we
+  * have to do the recursion for the children.
+  */
+ void
+ MemoryContextReset(MemoryContext context)
+ {
+ 	AssertArg(MemoryContextIsValid(context));
+ 
+ 	/* save a function call in common case where there are no children */
+ 	if (context->firstchild != NULL)
+ 		MemoryContextDeleteChildren(context);
+ 
+ 	/* Nothing to do if no pallocs since startup or last reset */
+ 	if (!context->isReset)
+ 	{
+ 		(*context->methods->reset) (context);
+ 		context->isReset = true;
+ 		VALGRIND_DESTROY_MEMPOOL(context);
+ 		VALGRIND_CREATE_MEMPOOL(context, 0, false);
+ 	}
+ }
+ 
+ /*
+  * MemoryContextResetButPreserveChildren
   *		Release all space allocated within a context and its descendants,
   *		but don't delete the contexts themselves.
   *
+  * Note: this was formerly the behavior of plain MemoryContextReset(), but
+  * we found out that you almost always want to delete children not keep them.
+  * This API may indeed have no use at all, but we keep it for the moment.
+  *
   * The type-specific reset routine handles the context itself, but we
   * have to do the recursion for the children.
   */
  void
! MemoryContextResetButPreserveChildren(MemoryContext context)
  {
  	AssertArg(MemoryContextIsValid(context));
  
*************** MemoryContextResetChildren(MemoryContext
*** 171,177 ****
  	AssertArg(MemoryContextIsValid(context));
  
  	for (child = context->firstchild; child != NULL; child = child->nextchild)
! 		MemoryContextReset(child);
  }
  
  /*
--- 202,208 ----
  	AssertArg(MemoryContextIsValid(context));
  
  	for (child = context->firstchild; child != NULL; child = child->nextchild)
! 		MemoryContextResetButPreserveChildren(child);
  }
  
  /*
*************** MemoryContextDeleteChildren(MemoryContex
*** 226,248 ****
  }
  
  /*
-  * MemoryContextResetAndDeleteChildren
-  *		Release all space allocated within a context and delete all
-  *		its descendants.
-  *
-  * This is a common combination case where we want to preserve the
-  * specific context but get rid of absolutely everything under it.
-  */
- void
- MemoryContextResetAndDeleteChildren(MemoryContext context)
- {
- 	AssertArg(MemoryContextIsValid(context));
- 
- 	MemoryContextDeleteChildren(context);
- 	MemoryContextReset(context);
- }
- 
- /*
   * MemoryContextSetParent
   *		Change a context to belong to a new parent (or no parent).
   *
--- 257,262 ----
diff --git a/src/include/utils/memutils.h b/src/include/utils/memutils.h
index 85aba7a..65e291e 100644
*** a/src/include/utils/memutils.h
--- b/src/include/utils/memutils.h
*************** extern PGDLLIMPORT MemoryContext CurTran
*** 84,89 ****
--- 84,92 ----
  /* This is a transient link to the active portal's memory context: */
  extern PGDLLIMPORT MemoryContext PortalContext;
  
+ /* Backwards compatibility macro */
+ #define MemoryContextResetAndDeleteChildren(ctx) MemoryContextReset(ctx)
+ 
  
  /*
   * Memory-context-type-independent functions in mcxt.c
*************** extern PGDLLIMPORT MemoryContext PortalC
*** 91,99 ****
  extern void MemoryContextInit(void);
  extern void MemoryContextReset(MemoryContext context);
  extern void MemoryContextDelete(MemoryContext context);
  extern void MemoryContextResetChildren(MemoryContext context);
  extern void MemoryContextDeleteChildren(MemoryContext context);
- extern void MemoryContextResetAndDeleteChildren(MemoryContext context);
  extern void MemoryContextSetParent(MemoryContext context,
  					   MemoryContext new_parent);
  extern Size GetMemoryChunkSpace(void *pointer);
--- 94,102 ----
  extern void MemoryContextInit(void);
  extern void MemoryContextReset(MemoryContext context);
  extern void MemoryContextDelete(MemoryContext context);
+ extern void MemoryContextResetButPreserveChildren(MemoryContext context);
  extern void MemoryContextResetChildren(MemoryContext context);
  extern void MemoryContextDeleteChildren(MemoryContext context);
  extern void MemoryContextSetParent(MemoryContext context,
  					   MemoryContext new_parent);
  extern Size GetMemoryChunkSpace(void *pointer);