show_planning_buffers-v1.diff

diff --git a/contrib/pg_stat_statements/pg_stat_statements.c b/contrib/pg_stat_statements/pg_stat_statements.c
index 63b5888ebb..eec3ae1be9 100644
--- a/contrib/pg_stat_statements/pg_stat_statements.c
+++ b/contrib/pg_stat_statements/pg_stat_statements.c
@@ -1021,30 +1021,7 @@ pgss_ProcessUtility(PlannedStmt *pstmt, const char *queryString,
 			rows = 0;
 
 		/* calc differences of buffer counters. */
-		bufusage.shared_blks_hit =
-			pgBufferUsage.shared_blks_hit - bufusage_start.shared_blks_hit;
-		bufusage.shared_blks_read =
-			pgBufferUsage.shared_blks_read - bufusage_start.shared_blks_read;
-		bufusage.shared_blks_dirtied =
-			pgBufferUsage.shared_blks_dirtied - bufusage_start.shared_blks_dirtied;
-		bufusage.shared_blks_written =
-			pgBufferUsage.shared_blks_written - bufusage_start.shared_blks_written;
-		bufusage.local_blks_hit =
-			pgBufferUsage.local_blks_hit - bufusage_start.local_blks_hit;
-		bufusage.local_blks_read =
-			pgBufferUsage.local_blks_read - bufusage_start.local_blks_read;
-		bufusage.local_blks_dirtied =
-			pgBufferUsage.local_blks_dirtied - bufusage_start.local_blks_dirtied;
-		bufusage.local_blks_written =
-			pgBufferUsage.local_blks_written - bufusage_start.local_blks_written;
-		bufusage.temp_blks_read =
-			pgBufferUsage.temp_blks_read - bufusage_start.temp_blks_read;
-		bufusage.temp_blks_written =
-			pgBufferUsage.temp_blks_written - bufusage_start.temp_blks_written;
-		bufusage.blk_read_time = pgBufferUsage.blk_read_time;
-		INSTR_TIME_SUBTRACT(bufusage.blk_read_time, bufusage_start.blk_read_time);
-		bufusage.blk_write_time = pgBufferUsage.blk_write_time;
-		INSTR_TIME_SUBTRACT(bufusage.blk_write_time, bufusage_start.blk_write_time);
+		bufusage = ComputeBufferCounters(&bufusage_start, &pgBufferUsage);
 
 		pgss_store(queryString,
 				   0,			/* signal that it's a utility stmt */
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 62fb3434a3..c2e7a3c8f1 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -360,7 +360,10 @@ ExplainOneQuery(Query *query, int cursorOptions,
 		PlannedStmt *plan;
 		instr_time	planstart,
 					planduration;
+		BufferUsage bufusage_start,
+					bufusage;
 
+		bufusage_start = pgBufferUsage;
 		INSTR_TIME_SET_CURRENT(planstart);
 
 		/* plan the query */
@@ -369,9 +372,12 @@ ExplainOneQuery(Query *query, int cursorOptions,
 		INSTR_TIME_SET_CURRENT(planduration);
 		INSTR_TIME_SUBTRACT(planduration, planstart);
 
+		/* calc differences of buffer counters. */
+		bufusage = ComputeBufferCounters(&bufusage_start, &pgBufferUsage);
+
 		/* run it (if needed) and produce output */
 		ExplainOnePlan(plan, into, es, queryString, params, queryEnv,
-					   &planduration);
+					   &planduration, &bufusage);
 	}
 }
 
@@ -464,7 +470,8 @@ ExplainOneUtility(Node *utilityStmt, IntoClause *into, ExplainState *es,
 void
 ExplainOnePlan(PlannedStmt *plannedstmt, IntoClause *into, ExplainState *es,
 			   const char *queryString, ParamListInfo params,
-			   QueryEnvironment *queryEnv, const instr_time *planduration)
+			   QueryEnvironment *queryEnv, const instr_time *planduration,
+			   const BufferUsage *bufusage)
 {
 	DestReceiver *dest;
 	QueryDesc  *queryDesc;
@@ -548,6 +555,9 @@ ExplainOnePlan(PlannedStmt *plannedstmt, IntoClause *into, ExplainState *es,
 	/* Create textual dump of plan tree */
 	ExplainPrintPlan(es, queryDesc);
 
+	if (es->summary && (planduration || es->buffers))
+		ExplainOpenGroup("Planning", "Planning", true, es);
+
 	if (es->summary && planduration)
 	{
 		double		plantime = INSTR_TIME_GET_DOUBLE(*planduration);
@@ -555,6 +565,16 @@ ExplainOnePlan(PlannedStmt *plannedstmt, IntoClause *into, ExplainState *es,
 		ExplainPropertyFloat("Planning Time", "ms", 1000.0 * plantime, 3, es);
 	}
 
+	if (es->summary && es->buffers)
+	{
+		es->indent += 1;
+		show_buffer_usage(es, bufusage);
+		es->indent -= 1;
+	}
+
+	if (es->summary && (planduration || es->buffers))
+		ExplainCloseGroup("Planning", "Planning", true, es);
+
 	/* Print info about runtime of triggers */
 	if (es->analyze)
 		ExplainPrintTriggers(es, queryDesc);
diff --git a/src/backend/commands/prepare.c b/src/backend/commands/prepare.c
index 7e0a041fab..0121961461 100644
--- a/src/backend/commands/prepare.c
+++ b/src/backend/commands/prepare.c
@@ -632,7 +632,10 @@ ExplainExecuteQuery(ExecuteStmt *execstmt, IntoClause *into, ExplainState *es,
 	EState	   *estate = NULL;
 	instr_time	planstart;
 	instr_time	planduration;
+	BufferUsage bufusage_start,
+				bufusage;
 
+	bufusage_start = pgBufferUsage;
 	INSTR_TIME_SET_CURRENT(planstart);
 
 	/* Look it up in the hash table */
@@ -665,6 +668,9 @@ ExplainExecuteQuery(ExecuteStmt *execstmt, IntoClause *into, ExplainState *es,
 	INSTR_TIME_SET_CURRENT(planduration);
 	INSTR_TIME_SUBTRACT(planduration, planstart);
 
+	/* calc differences of buffer counters. */
+	bufusage = ComputeBufferCounters(&bufusage_start, &pgBufferUsage);
+
 	plan_list = cplan->stmt_list;
 
 	/* Explain each query */
@@ -674,7 +680,7 @@ ExplainExecuteQuery(ExecuteStmt *execstmt, IntoClause *into, ExplainState *es,
 
 		if (pstmt->commandType != CMD_UTILITY)
 			ExplainOnePlan(pstmt, into, es, query_string, paramLI, queryEnv,
-						   &planduration);
+						   &planduration, &bufusage);
 		else
 			ExplainOneUtility(pstmt->utilityStmt, into, es, query_string,
 							  paramLI, queryEnv);
diff --git a/src/backend/executor/instrument.c b/src/backend/executor/instrument.c
index bd36f8ee68..86296f8109 100644
--- a/src/backend/executor/instrument.c
+++ b/src/backend/executor/instrument.c
@@ -25,6 +25,35 @@ static void BufferUsageAccumDiff(BufferUsage *dst,
 								 const BufferUsage *add, const BufferUsage *sub);
 
 
+/* Compute the difference between two BufferUsage */
+BufferUsage
+ComputeBufferCounters(BufferUsage *start, BufferUsage *stop)
+{
+	BufferUsage result;
+
+	result.shared_blks_hit = stop->shared_blks_hit - start->shared_blks_hit;
+	result.shared_blks_read = stop->shared_blks_read - start->shared_blks_read;
+	result.shared_blks_dirtied = stop->shared_blks_dirtied -
+		start->shared_blks_dirtied;
+	result.shared_blks_written = stop->shared_blks_written -
+		start->shared_blks_written;
+	result.local_blks_hit = stop->local_blks_hit - start->local_blks_hit;
+	result.local_blks_read = stop->local_blks_read - start->local_blks_read;
+	result.local_blks_dirtied = stop->local_blks_dirtied -
+		start->local_blks_dirtied;
+	result.local_blks_written = stop->local_blks_written -
+		start->local_blks_written;
+	result.temp_blks_read = stop->temp_blks_read - start->temp_blks_read;
+	result.temp_blks_written = stop->temp_blks_written -
+		start->temp_blks_written;
+	result.blk_read_time = stop->blk_read_time;
+	INSTR_TIME_SUBTRACT(result.blk_read_time, start->blk_read_time);
+	result.blk_write_time = stop->blk_write_time;
+	INSTR_TIME_SUBTRACT(result.blk_write_time, start->blk_write_time);
+
+	return result;
+}
+
 /* Allocate new instrumentation structure(s) */
 Instrumentation *
 InstrAlloc(int n, int instrument_options)
diff --git a/src/include/commands/explain.h b/src/include/commands/explain.h
index 8639891c16..7afd9afc79 100644
--- a/src/include/commands/explain.h
+++ b/src/include/commands/explain.h
@@ -77,7 +77,8 @@ extern void ExplainOneUtility(Node *utilityStmt, IntoClause *into,
 extern void ExplainOnePlan(PlannedStmt *plannedstmt, IntoClause *into,
 						   ExplainState *es, const char *queryString,
 						   ParamListInfo params, QueryEnvironment *queryEnv,
-						   const instr_time *planduration);
+						   const instr_time *planduration,
+						   const BufferUsage *bufusage);
 
 extern void ExplainPrintPlan(ExplainState *es, QueryDesc *queryDesc);
 extern void ExplainPrintTriggers(ExplainState *es, QueryDesc *queryDesc);
diff --git a/src/include/executor/instrument.h b/src/include/executor/instrument.h
index 70d8632305..0df539af0f 100644
--- a/src/include/executor/instrument.h
+++ b/src/include/executor/instrument.h
@@ -72,6 +72,7 @@ typedef struct WorkerInstrumentation
 
 extern PGDLLIMPORT BufferUsage pgBufferUsage;
 
+extern BufferUsage ComputeBufferCounters(BufferUsage *start, BufferUsage *stop);
 extern Instrumentation *InstrAlloc(int n, int instrument_options);
 extern void InstrInit(Instrumentation *instr, int instrument_options);
 extern void InstrStartNode(Instrumentation *instr);