2 files changed, 147 insertions, 27 deletions

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 843472e6ddc..83d00a46638 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -119,9 +119,11 @@ static void show_instrumentation_count(const char *qlabel, int which,
 static void show_foreignscan_info(ForeignScanState *fsstate, ExplainState *es);
 static void show_eval_params(Bitmapset *bms_params, ExplainState *es);
 static const char *explain_get_index_name(Oid indexId);
-static void show_buffer_usage(ExplainState *es, const BufferUsage *usage,
-							  bool planning);
+static bool peek_buffer_usage(ExplainState *es, const BufferUsage *usage);
+static void show_buffer_usage(ExplainState *es, const BufferUsage *usage);
 static void show_wal_usage(ExplainState *es, const WalUsage *usage);
+static void show_memory_counters(ExplainState *es,
+								 const MemoryContextCounters *mem_counters);
 static void ExplainIndexScanDetails(Oid indexid, ScanDirection indexorderdir,
 									ExplainState *es);
 static void ExplainScanTarget(Scan *plan, ExplainState *es);
@@ -202,6 +204,8 @@ ExplainQuery(ParseState *pstate, ExplainStmt *stmt,
 			summary_set = true;
 			es->summary = defGetBoolean(opt);
 		}
+		else if (strcmp(opt->defname, "memory") == 0)
+			es->memory = defGetBoolean(opt);
 		else if (strcmp(opt->defname, "format") == 0)
 		{
 			char	   *p = defGetString(opt);
@@ -397,6 +401,25 @@ ExplainOneQuery(Query *query, int cursorOptions,
 					planduration;
 		BufferUsage bufusage_start,
 					bufusage;
+		MemoryContextCounters mem_counters;
+		MemoryContext planner_ctx = NULL;
+		MemoryContext saved_ctx = NULL;
+
+		if (es->memory)
+		{
+			/*
+			 * Create a new memory context to measure planner's memory
+			 * consumption accurately.  Note that if the planner were to be
+			 * modified to use a different memory context type, here we would
+			 * be changing that to AllocSet, which might be undesirable.
+			 * However, we don't have a way to create a context of the same
+			 * type as another, so we pray and hope that this is OK.
+			 */
+			planner_ctx = AllocSetContextCreate(CurrentMemoryContext,
+												"explain analyze planner context",
+												ALLOCSET_DEFAULT_SIZES);
+			saved_ctx = MemoryContextSwitchTo(planner_ctx);
+		}
 
 		if (es->buffers)
 			bufusage_start = pgBufferUsage;
@@ -408,6 +431,12 @@ ExplainOneQuery(Query *query, int cursorOptions,
 		INSTR_TIME_SET_CURRENT(planduration);
 		INSTR_TIME_SUBTRACT(planduration, planstart);
 
+		if (es->memory)
+		{
+			MemoryContextSwitchTo(saved_ctx);
+			MemoryContextMemConsumed(planner_ctx, &mem_counters);
+		}
+
 		/* calc differences of buffer counters. */
 		if (es->buffers)
 		{
@@ -417,7 +446,8 @@ ExplainOneQuery(Query *query, int cursorOptions,
 
 		/* run it (if needed) and produce output */
 		ExplainOnePlan(plan, into, es, queryString, params, queryEnv,
-					   &planduration, (es->buffers ? &bufusage : NULL));
+					   &planduration, (es->buffers ? &bufusage : NULL),
+					   es->memory ? &mem_counters : NULL);
 	}
 }
 
@@ -527,7 +557,8 @@ void
 ExplainOnePlan(PlannedStmt *plannedstmt, IntoClause *into, ExplainState *es,
 			   const char *queryString, ParamListInfo params,
 			   QueryEnvironment *queryEnv, const instr_time *planduration,
-			   const BufferUsage *bufusage)
+			   const BufferUsage *bufusage,
+			   const MemoryContextCounters *mem_counters)
 {
 	DestReceiver *dest;
 	QueryDesc  *queryDesc;
@@ -615,11 +646,27 @@ ExplainOnePlan(PlannedStmt *plannedstmt, IntoClause *into, ExplainState *es,
 	/* Create textual dump of plan tree */
 	ExplainPrintPlan(es, queryDesc);
 
-	/* Show buffer usage in planning */
-	if (bufusage)
+	/* Show buffer and/or memory usage in planning */
+	if (peek_buffer_usage(es, bufusage) || mem_counters)
 	{
 		ExplainOpenGroup("Planning", "Planning", true, es);
-		show_buffer_usage(es, bufusage, true);
+
+		if (es->format == EXPLAIN_FORMAT_TEXT)
+		{
+			ExplainIndentText(es);
+			appendStringInfoString(es->str, "Planning:\n");
+			es->indent++;
+		}
+
+		if (bufusage)
+			show_buffer_usage(es, bufusage);
+
+		if (mem_counters)
+			show_memory_counters(es, mem_counters);
+
+		if (es->format == EXPLAIN_FORMAT_TEXT)
+			es->indent--;
+
 		ExplainCloseGroup("Planning", "Planning", true, es);
 	}
 
@@ -2106,7 +2153,7 @@ ExplainNode(PlanState *planstate, List *ancestors,
 
 	/* Show buffer/WAL usage */
 	if (es->buffers && planstate->instrument)
-		show_buffer_usage(es, &planstate->instrument->bufusage, false);
+		show_buffer_usage(es, &planstate->instrument->bufusage);
 	if (es->wal && planstate->instrument)
 		show_wal_usage(es, &planstate->instrument->walusage);
 
@@ -2125,7 +2172,7 @@ ExplainNode(PlanState *planstate, List *ancestors,
 
 			ExplainOpenWorker(n, es);
 			if (es->buffers)
-				show_buffer_usage(es, &instrument->bufusage, false);
+				show_buffer_usage(es, &instrument->bufusage);
 			if (es->wal)
 				show_wal_usage(es, &instrument->walusage);
 			ExplainCloseWorker(n, es);
@@ -3545,10 +3592,52 @@ explain_get_index_name(Oid indexId)
 }
 
 /*
- * Show buffer usage details.
+ * Return whether show_buffer_usage would have anything to print, if given
+ * the same 'usage' data.  Note that when the format is anything other than
+ * text, we print even if the counters are all zeroes.
+ */
+static bool
+peek_buffer_usage(ExplainState *es, const BufferUsage *usage)
+{
+	bool		has_shared;
+	bool		has_local;
+	bool		has_temp;
+	bool		has_shared_timing;
+	bool		has_local_timing;
+	bool		has_temp_timing;
+
+	if (usage == NULL)
+		return false;
+
+	if (es->format != EXPLAIN_FORMAT_TEXT)
+		return true;
+
+	has_shared = (usage->shared_blks_hit > 0 ||
+				  usage->shared_blks_read > 0 ||
+				  usage->shared_blks_dirtied > 0 ||
+				  usage->shared_blks_written > 0);
+	has_local = (usage->local_blks_hit > 0 ||
+				 usage->local_blks_read > 0 ||
+				 usage->local_blks_dirtied > 0 ||
+				 usage->local_blks_written > 0);
+	has_temp = (usage->temp_blks_read > 0 ||
+				usage->temp_blks_written > 0);
+	has_shared_timing = (!INSTR_TIME_IS_ZERO(usage->shared_blk_read_time) ||
+						 !INSTR_TIME_IS_ZERO(usage->shared_blk_write_time));
+	has_local_timing = (!INSTR_TIME_IS_ZERO(usage->local_blk_read_time) ||
+						!INSTR_TIME_IS_ZERO(usage->local_blk_write_time));
+	has_temp_timing = (!INSTR_TIME_IS_ZERO(usage->temp_blk_read_time) ||
+					   !INSTR_TIME_IS_ZERO(usage->temp_blk_write_time));
+
+	return has_shared || has_local || has_temp || has_shared_timing ||
+		has_local_timing || has_temp_timing;
+}
+
+/*
+ * Show buffer usage details.  This better be sync with peek_buffer_usage.
  */
 static void
-show_buffer_usage(ExplainState *es, const BufferUsage *usage, bool planning)
+show_buffer_usage(ExplainState *es, const BufferUsage *usage)
 {
 	if (es->format == EXPLAIN_FORMAT_TEXT)
 	{
@@ -3568,18 +3657,6 @@ show_buffer_usage(ExplainState *es, const BufferUsage *usage, bool planning)
 										!INSTR_TIME_IS_ZERO(usage->local_blk_write_time));
 		bool		has_temp_timing = (!INSTR_TIME_IS_ZERO(usage->temp_blk_read_time) ||
 									   !INSTR_TIME_IS_ZERO(usage->temp_blk_write_time));
-		bool		show_planning = (planning && (has_shared ||
-												  has_local || has_temp ||
-												  has_shared_timing ||
-												  has_local_timing ||
-												  has_temp_timing));
-
-		if (show_planning)
-		{
-			ExplainIndentText(es);
-			appendStringInfoString(es->str, "Planning:\n");
-			es->indent++;
-		}
 
 		/* Show only positive counter values. */
 		if (has_shared || has_local || has_temp)
@@ -3678,9 +3755,6 @@ show_buffer_usage(ExplainState *es, const BufferUsage *usage, bool planning)
 			}
 			appendStringInfoChar(es->str, '\n');
 		}
-
-		if (show_planning)
-			es->indent--;
 	}
 	else
 	{
@@ -3767,6 +3841,32 @@ show_wal_usage(ExplainState *es, const WalUsage *usage)
 }
 
 /*
+ * Show memory usage details.
+ */
+static void
+show_memory_counters(ExplainState *es, const MemoryContextCounters *mem_counters)
+{
+	if (es->format == EXPLAIN_FORMAT_TEXT)
+	{
+		ExplainIndentText(es);
+		appendStringInfo(es->str,
+						 "Memory: used=%lld bytes  allocated=%lld bytes",
+						 (long long) (mem_counters->totalspace - mem_counters->freespace),
+						 (long long) mem_counters->totalspace);
+		appendStringInfoChar(es->str, '\n');
+	}
+	else
+	{
+		ExplainPropertyInteger("Memory Used", "bytes",
+							   mem_counters->totalspace - mem_counters->freespace,
+							   es);
+		ExplainPropertyInteger("Memory Allocated", "bytes",
+							   mem_counters->totalspace, es);
+	}
+}
+
+
+/*
  * Add some additional details about an IndexScan or IndexOnlyScan
  */
 static void
diff --git a/src/backend/commands/prepare.c b/src/backend/commands/prepare.c
index 703976f6335..bf1579d36d7 100644
--- a/src/backend/commands/prepare.c
+++ b/src/backend/commands/prepare.c
@@ -583,6 +583,19 @@ ExplainExecuteQuery(ExecuteStmt *execstmt, IntoClause *into, ExplainState *es,
 	instr_time	planduration;
 	BufferUsage bufusage_start,
 				bufusage;
+	MemoryContextCounters mem_counters;
+	MemoryContext planner_ctx = NULL;
+	MemoryContext saved_ctx = NULL;
+
+	if (es->memory)
+	{
+		/* See ExplainOneQuery about this */
+		Assert(IsA(CurrentMemoryContext, AllocSetContext));
+		planner_ctx = AllocSetContextCreate(CurrentMemoryContext,
+											"explain analyze planner context",
+											ALLOCSET_DEFAULT_SIZES);
+		saved_ctx = MemoryContextSwitchTo(planner_ctx);
+	}
 
 	if (es->buffers)
 		bufusage_start = pgBufferUsage;
@@ -624,6 +637,12 @@ ExplainExecuteQuery(ExecuteStmt *execstmt, IntoClause *into, ExplainState *es,
 	INSTR_TIME_SET_CURRENT(planduration);
 	INSTR_TIME_SUBTRACT(planduration, planstart);
 
+	if (es->memory)
+	{
+		MemoryContextSwitchTo(saved_ctx);
+		MemoryContextMemConsumed(planner_ctx, &mem_counters);
+	}
+
 	/* calc differences of buffer counters. */
 	if (es->buffers)
 	{
@@ -640,7 +659,8 @@ ExplainExecuteQuery(ExecuteStmt *execstmt, IntoClause *into, ExplainState *es,
 
 		if (pstmt->commandType != CMD_UTILITY)
 			ExplainOnePlan(pstmt, into, es, query_string, paramLI, queryEnv,
-						   &planduration, (es->buffers ? &bufusage : NULL));
+						   &planduration, (es->buffers ? &bufusage : NULL),
+						   es->memory ? &mem_counters : NULL);
 		else
 			ExplainOneUtility(pstmt->utilityStmt, into, es, query_string,
 							  paramLI, queryEnv);