Add macros to make AllocSetContextCreate() calls simpler and safer.

I found that half a dozen (nearly 5%) of our AllocSetContextCreate calls
had typos in the context-sizing parameters.  While none of these led to
especially significant problems, they did create minor inefficiencies,
and it's now clear that expecting people to copy-and-paste those calls
accurately is not a great idea.  Let's reduce the risk of future errors
by introducing single macros that encapsulate the common use-cases.
Three such macros are enough to cover all but two special-purpose contexts;
those two calls can be left as-is, I think.

While this patch doesn't in itself improve matters for third-party
extensions, it doesn't break anything for them either, and they can
gradually adopt the simplified notation over time.

In passing, change TopMemoryContext to use the default allocation
parameters.  Formerly it could only be extended 8K at a time.  That was
probably reasonable when this code was written; but nowadays we create
many more contexts than we did then, so that it's not unusual to have a
couple hundred K in TopMemoryContext, even without considering various
dubious code that sticks other things there.  There seems no good reason
not to let it use growing blocks like most other contexts.

Back-patch to 9.6, mostly because that's still close enough to HEAD that
it's easy to do so, and keeping the branches in sync can be expected to
avoid some future back-patching pain.  The bugs fixed by these changes
don't seem to be significant enough to justify fixing them further back.

Discussion: <21072.1472321324@sss.pgh.pa.us>

11 files changed, 27 insertions, 74 deletions

diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c
index e937cf8e7e..a3bcb100da 100644
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@@ -80,9 +80,7 @@ CreateExecutorState(void)
 	 */
 	qcontext = AllocSetContextCreate(CurrentMemoryContext,
 									 "ExecutorState",
-									 ALLOCSET_DEFAULT_MINSIZE,
-									 ALLOCSET_DEFAULT_INITSIZE,
-									 ALLOCSET_DEFAULT_MAXSIZE);
+									 ALLOCSET_DEFAULT_SIZES);
 
 	/*
 	 * Make the EState node within the per-query context.  This way, we don't
@@ -229,9 +227,7 @@ CreateExprContext(EState *estate)
 	econtext->ecxt_per_tuple_memory =
 		AllocSetContextCreate(estate->es_query_cxt,
 							  "ExprContext",
-							  ALLOCSET_DEFAULT_MINSIZE,
-							  ALLOCSET_DEFAULT_INITSIZE,
-							  ALLOCSET_DEFAULT_MAXSIZE);
+							  ALLOCSET_DEFAULT_SIZES);
 
 	econtext->ecxt_param_exec_vals = estate->es_param_exec_vals;
 	econtext->ecxt_param_list_info = estate->es_param_list_info;
@@ -300,9 +296,7 @@ CreateStandaloneExprContext(void)
 	econtext->ecxt_per_tuple_memory =
 		AllocSetContextCreate(CurrentMemoryContext,
 							  "ExprContext",
-							  ALLOCSET_DEFAULT_MINSIZE,
-							  ALLOCSET_DEFAULT_INITSIZE,
-							  ALLOCSET_DEFAULT_MAXSIZE);
+							  ALLOCSET_DEFAULT_SIZES);
 
 	econtext->ecxt_param_exec_vals = NULL;
 	econtext->ecxt_param_list_info = NULL;
diff --git a/src/backend/executor/functions.c b/src/backend/executor/functions.c
index e02fba5232..470db5bb4a 100644
--- a/src/backend/executor/functions.c
+++ b/src/backend/executor/functions.c
@@ -600,9 +600,7 @@ init_sql_fcache(FmgrInfo *finfo, Oid collation, bool lazyEvalOK)
 	 */
 	fcontext = AllocSetContextCreate(finfo->fn_mcxt,
 									 "SQL function data",
-									 ALLOCSET_DEFAULT_MINSIZE,
-									 ALLOCSET_DEFAULT_INITSIZE,
-									 ALLOCSET_DEFAULT_MAXSIZE);
+									 ALLOCSET_DEFAULT_SIZES);
 
 	oldcontext = MemoryContextSwitchTo(fcontext);
 
diff --git a/src/backend/executor/nodeFunctionscan.c b/src/backend/executor/nodeFunctionscan.c
index a03f6e73fd..5a0f324de0 100644
--- a/src/backend/executor/nodeFunctionscan.c
+++ b/src/backend/executor/nodeFunctionscan.c
@@ -508,9 +508,7 @@ ExecInitFunctionScan(FunctionScan *node, EState *estate, int eflags)
 	 */
 	scanstate->argcontext = AllocSetContextCreate(CurrentMemoryContext,
 												  "Table function arguments",
-												  ALLOCSET_DEFAULT_MINSIZE,
-												  ALLOCSET_DEFAULT_INITSIZE,
-												  ALLOCSET_DEFAULT_MAXSIZE);
+												  ALLOCSET_DEFAULT_SIZES);
 
 	return scanstate;
 }
diff --git a/src/backend/executor/nodeHash.c b/src/backend/executor/nodeHash.c
index 9ed09a7b0c..6375d9bfda 100644
--- a/src/backend/executor/nodeHash.c
+++ b/src/backend/executor/nodeHash.c
@@ -344,15 +344,11 @@ ExecHashTableCreate(Hash *node, List *hashOperators, bool keepNulls)
 	 */
 	hashtable->hashCxt = AllocSetContextCreate(CurrentMemoryContext,
 											   "HashTableContext",
-											   ALLOCSET_DEFAULT_MINSIZE,
-											   ALLOCSET_DEFAULT_INITSIZE,
-											   ALLOCSET_DEFAULT_MAXSIZE);
+											   ALLOCSET_DEFAULT_SIZES);
 
 	hashtable->batchCxt = AllocSetContextCreate(hashtable->hashCxt,
 												"HashBatchContext",
-												ALLOCSET_DEFAULT_MINSIZE,
-												ALLOCSET_DEFAULT_INITSIZE,
-												ALLOCSET_DEFAULT_MAXSIZE);
+												ALLOCSET_DEFAULT_SIZES);
 
 	/* Allocate data that will live for the life of the hashjoin */
 
diff --git a/src/backend/executor/nodeRecursiveunion.c b/src/backend/executor/nodeRecursiveunion.c
index e76405a56e..39be191c45 100644
--- a/src/backend/executor/nodeRecursiveunion.c
+++ b/src/backend/executor/nodeRecursiveunion.c
@@ -200,15 +200,11 @@ ExecInitRecursiveUnion(RecursiveUnion *node, EState *estate, int eflags)
 		rustate->tempContext =
 			AllocSetContextCreate(CurrentMemoryContext,
 								  "RecursiveUnion",
-								  ALLOCSET_DEFAULT_MINSIZE,
-								  ALLOCSET_DEFAULT_INITSIZE,
-								  ALLOCSET_DEFAULT_MAXSIZE);
+								  ALLOCSET_DEFAULT_SIZES);
 		rustate->tableContext =
 			AllocSetContextCreate(CurrentMemoryContext,
 								  "RecursiveUnion hash table",
-								  ALLOCSET_DEFAULT_MINSIZE,
-								  ALLOCSET_DEFAULT_INITSIZE,
-								  ALLOCSET_DEFAULT_MAXSIZE);
+								  ALLOCSET_DEFAULT_SIZES);
 	}
 
 	/*
diff --git a/src/backend/executor/nodeSetOp.c b/src/backend/executor/nodeSetOp.c
index 2d81d46927..633580b436 100644
--- a/src/backend/executor/nodeSetOp.c
+++ b/src/backend/executor/nodeSetOp.c
@@ -507,9 +507,7 @@ ExecInitSetOp(SetOp *node, EState *estate, int eflags)
 	setopstate->tempContext =
 		AllocSetContextCreate(CurrentMemoryContext,
 							  "SetOp",
-							  ALLOCSET_DEFAULT_MINSIZE,
-							  ALLOCSET_DEFAULT_INITSIZE,
-							  ALLOCSET_DEFAULT_MAXSIZE);
+							  ALLOCSET_DEFAULT_SIZES);
 
 	/*
 	 * If hashing, we also need a longer-lived context to store the hash
@@ -520,9 +518,7 @@ ExecInitSetOp(SetOp *node, EState *estate, int eflags)
 		setopstate->tableContext =
 			AllocSetContextCreate(CurrentMemoryContext,
 								  "SetOp hash table",
-								  ALLOCSET_DEFAULT_MINSIZE,
-								  ALLOCSET_DEFAULT_INITSIZE,
-								  ALLOCSET_DEFAULT_MAXSIZE);
+								  ALLOCSET_DEFAULT_SIZES);
 
 	/*
 	 * Tuple table initialization
diff --git a/src/backend/executor/nodeSubplan.c b/src/backend/executor/nodeSubplan.c
index e503494edd..2cf169f956 100644
--- a/src/backend/executor/nodeSubplan.c
+++ b/src/backend/executor/nodeSubplan.c
@@ -776,16 +776,12 @@ ExecInitSubPlan(SubPlan *subplan, PlanState *parent)
 		sstate->hashtablecxt =
 			AllocSetContextCreate(CurrentMemoryContext,
 								  "Subplan HashTable Context",
-								  ALLOCSET_DEFAULT_MINSIZE,
-								  ALLOCSET_DEFAULT_INITSIZE,
-								  ALLOCSET_DEFAULT_MAXSIZE);
+								  ALLOCSET_DEFAULT_SIZES);
 		/* and a small one for the hash tables to use as temp storage */
 		sstate->hashtempcxt =
 			AllocSetContextCreate(CurrentMemoryContext,
 								  "Subplan HashTable Temp Context",
-								  ALLOCSET_SMALL_MINSIZE,
-								  ALLOCSET_SMALL_INITSIZE,
-								  ALLOCSET_SMALL_MAXSIZE);
+								  ALLOCSET_SMALL_SIZES);
 		/* and a short-lived exprcontext for function evaluation */
 		sstate->innerecontext = CreateExprContext(estate);
 		/* Silly little array of column numbers 1..n */
diff --git a/src/backend/executor/nodeUnique.c b/src/backend/executor/nodeUnique.c
index 4caae34b97..f45c79232d 100644
--- a/src/backend/executor/nodeUnique.c
+++ b/src/backend/executor/nodeUnique.c
@@ -133,9 +133,7 @@ ExecInitUnique(Unique *node, EState *estate, int eflags)
 	uniquestate->tempContext =
 		AllocSetContextCreate(CurrentMemoryContext,
 							  "Unique",
-							  ALLOCSET_DEFAULT_MINSIZE,
-							  ALLOCSET_DEFAULT_INITSIZE,
-							  ALLOCSET_DEFAULT_MAXSIZE);
+							  ALLOCSET_DEFAULT_SIZES);
 
 	/*
 	 * Tuple table initialization
diff --git a/src/backend/executor/nodeWindowAgg.c b/src/backend/executor/nodeWindowAgg.c
index d4c88a1f0e..371548ceb3 100644
--- a/src/backend/executor/nodeWindowAgg.c
+++ b/src/backend/executor/nodeWindowAgg.c
@@ -1801,10 +1801,8 @@ ExecInitWindowAgg(WindowAgg *node, EState *estate, int eflags)
 	/* Create long-lived context for storage of partition-local memory etc */
 	winstate->partcontext =
 		AllocSetContextCreate(CurrentMemoryContext,
-							  "WindowAgg_Partition",
-							  ALLOCSET_DEFAULT_MINSIZE,
-							  ALLOCSET_DEFAULT_INITSIZE,
-							  ALLOCSET_DEFAULT_MAXSIZE);
+							  "WindowAgg Partition",
+							  ALLOCSET_DEFAULT_SIZES);
 
 	/*
 	 * Create mid-lived context for aggregate trans values etc.
@@ -1814,10 +1812,8 @@ ExecInitWindowAgg(WindowAgg *node, EState *estate, int eflags)
 	 */
 	winstate->aggcontext =
 		AllocSetContextCreate(CurrentMemoryContext,
-							  "WindowAgg_Aggregates",
-							  ALLOCSET_DEFAULT_MINSIZE,
-							  ALLOCSET_DEFAULT_INITSIZE,
-							  ALLOCSET_DEFAULT_MAXSIZE);
+							  "WindowAgg Aggregates",
+							  ALLOCSET_DEFAULT_SIZES);
 
 	/*
 	 * tuple table initialization
@@ -2321,10 +2317,8 @@ initialize_peragg(WindowAggState *winstate, WindowFunc *wfunc,
 	if (OidIsValid(invtransfn_oid))
 		peraggstate->aggcontext =
 			AllocSetContextCreate(CurrentMemoryContext,
-								  "WindowAgg_AggregatePrivate",
-								  ALLOCSET_DEFAULT_MINSIZE,
-								  ALLOCSET_DEFAULT_INITSIZE,
-								  ALLOCSET_DEFAULT_MAXSIZE);
+								  "WindowAgg Per Aggregate",
+								  ALLOCSET_DEFAULT_SIZES);
 	else
 		peraggstate->aggcontext = winstate->aggcontext;
 
diff --git a/src/backend/executor/spi.c b/src/backend/executor/spi.c
index 38de18006d..38767ae4ce 100644
--- a/src/backend/executor/spi.c
+++ b/src/backend/executor/spi.c
@@ -142,14 +142,10 @@ SPI_connect(void)
 	 */
 	_SPI_current->procCxt = AllocSetContextCreate(TopTransactionContext,
 												  "SPI Proc",
-												  ALLOCSET_DEFAULT_MINSIZE,
-												  ALLOCSET_DEFAULT_INITSIZE,
-												  ALLOCSET_DEFAULT_MAXSIZE);
+												  ALLOCSET_DEFAULT_SIZES);
 	_SPI_current->execCxt = AllocSetContextCreate(TopTransactionContext,
 												  "SPI Exec",
-												  ALLOCSET_DEFAULT_MINSIZE,
-												  ALLOCSET_DEFAULT_INITSIZE,
-												  ALLOCSET_DEFAULT_MAXSIZE);
+												  ALLOCSET_DEFAULT_SIZES);
 	/* ... and switch to procedure's context */
 	_SPI_current->savedcxt = MemoryContextSwitchTo(_SPI_current->procCxt);
 
@@ -1744,9 +1740,7 @@ spi_dest_startup(DestReceiver *self, int operation, TupleDesc typeinfo)
 
 	tuptabcxt = AllocSetContextCreate(CurrentMemoryContext,
 									  "SPI TupTable",
-									  ALLOCSET_DEFAULT_MINSIZE,
-									  ALLOCSET_DEFAULT_INITSIZE,
-									  ALLOCSET_DEFAULT_MAXSIZE);
+									  ALLOCSET_DEFAULT_SIZES);
 	MemoryContextSwitchTo(tuptabcxt);
 
 	_SPI_current->tuptable = tuptable = (SPITupleTable *)
@@ -2615,14 +2609,11 @@ _SPI_make_plan_non_temp(SPIPlanPtr plan)
 
 	/*
 	 * Create a memory context for the plan, underneath the procedure context.
-	 * We don't expect the plan to be very large, so use smaller-than-default
-	 * alloc parameters.
+	 * We don't expect the plan to be very large.
 	 */
 	plancxt = AllocSetContextCreate(parentcxt,
 									"SPI Plan",
-									ALLOCSET_SMALL_MINSIZE,
-									ALLOCSET_SMALL_INITSIZE,
-									ALLOCSET_SMALL_MAXSIZE);
+									ALLOCSET_SMALL_SIZES);
 	oldcxt = MemoryContextSwitchTo(plancxt);
 
 	/* Copy the SPI_plan struct and subsidiary data into the new context */
@@ -2689,9 +2680,7 @@ _SPI_save_plan(SPIPlanPtr plan)
 	 */
 	plancxt = AllocSetContextCreate(CurrentMemoryContext,
 									"SPI Plan",
-									ALLOCSET_SMALL_MINSIZE,
-									ALLOCSET_SMALL_INITSIZE,
-									ALLOCSET_SMALL_MAXSIZE);
+									ALLOCSET_SMALL_SIZES);
 	oldcxt = MemoryContextSwitchTo(plancxt);
 
 	/* Copy the SPI plan into its own context */
diff --git a/src/backend/executor/tqueue.c b/src/backend/executor/tqueue.c
index 58d0eeaf0b..344e623c94 100644
--- a/src/backend/executor/tqueue.c
+++ b/src/backend/executor/tqueue.c
@@ -281,9 +281,7 @@ tqueueReceiveSlot(TupleTableSlot *slot, DestReceiver *self)
 					tqueue->tmpcontext =
 						AllocSetContextCreate(tqueue->mycontext,
 											  "tqueue sender temp context",
-											  ALLOCSET_DEFAULT_MINSIZE,
-											  ALLOCSET_DEFAULT_INITSIZE,
-											  ALLOCSET_DEFAULT_MAXSIZE);
+											  ALLOCSET_DEFAULT_SIZES);
 				oldcontext = MemoryContextSwitchTo(tqueue->tmpcontext);
 			}