Add an EXPLAIN (BUFFERS) option to show buffer-usage statistics.

This patch also removes buffer-usage statistics from the track_counts
output, since this (or the global server statistics) is deemed to be a better
interface to this information.

Itagaki Takahiro, reviewed by Euler Taveira de Oliveira.

3 files changed, 31 insertions, 7 deletions

diff --git a/src/include/executor/execdesc.h b/src/include/executor/execdesc.h
index 9682c4b73ad..46df1bf6bd2 100644
--- a/src/include/executor/execdesc.h
+++ b/src/include/executor/execdesc.h
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/executor/execdesc.h,v 1.40 2009/01/02 20:42:00 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/executor/execdesc.h,v 1.41 2009/12/15 04:57:48 rhaas Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -42,7 +42,7 @@ typedef struct QueryDesc
 	Snapshot	crosscheck_snapshot;	/* crosscheck for RI update/delete */
 	DestReceiver *dest;			/* the destination for tuple output */
 	ParamListInfo params;		/* param values being passed in */
-	bool		doInstrument;	/* TRUE requests runtime instrumentation */
+	int			instrument_options;		/* OR of InstrumentOption flags */
 
 	/* These fields are set by ExecutorStart */
 	TupleDesc	tupDesc;		/* descriptor for result tuples */
@@ -60,7 +60,7 @@ extern QueryDesc *CreateQueryDesc(PlannedStmt *plannedstmt,
 				Snapshot crosscheck_snapshot,
 				DestReceiver *dest,
 				ParamListInfo params,
-				bool doInstrument);
+				int instrument_options);
 
 extern QueryDesc *CreateUtilityQueryDesc(Node *utilitystmt,
 					   const char *sourceText,
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 76c075f75f9..98f8063601a 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/executor/executor.h,v 1.164 2009/12/07 05:22:23 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/executor/executor.h,v 1.165 2009/12/15 04:57:48 rhaas Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -161,7 +161,7 @@ extern void InitResultRelInfo(ResultRelInfo *resultRelInfo,
 				  Relation resultRelationDesc,
 				  Index resultRelationIndex,
 				  CmdType operation,
-				  bool doInstrument);
+				  int instrument_options);
 extern ResultRelInfo *ExecGetTriggerResultRel(EState *estate, Oid relid);
 extern bool ExecContextForcesOids(PlanState *planstate, bool *hasoids);
 extern void ExecConstraints(ResultRelInfo *resultRelInfo,
diff --git a/src/include/executor/instrument.h b/src/include/executor/instrument.h
index 1ae6eebe8d3..5eea68d2fee 100644
--- a/src/include/executor/instrument.h
+++ b/src/include/executor/instrument.h
@@ -6,7 +6,7 @@
  *
  * Copyright (c) 2001-2009, PostgreSQL Global Development Group
  *
- * $PostgreSQL: pgsql/src/include/executor/instrument.h,v 1.20 2009/01/01 17:23:59 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/executor/instrument.h,v 1.21 2009/12/15 04:57:48 rhaas Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -16,22 +16,46 @@
 #include "portability/instr_time.h"
 
 
+typedef struct BufferUsage
+{
+	long	shared_blks_hit;		/* # of shared buffer hits */
+	long	shared_blks_read;		/* # of shared disk blocks read */
+	long	shared_blks_written;	/* # of shared disk blocks written */
+	long	local_blks_hit;			/* # of local buffer hits */
+	long	local_blks_read;		/* # of local disk blocks read */
+	long	local_blks_written;		/* # of local disk blocks written */
+	long	temp_blks_read;			/* # of temp blocks read */
+	long	temp_blks_written;		/* # of temp blocks written */
+} BufferUsage;
+
+typedef enum InstrumentOption
+{
+	INSTRUMENT_TIMER	= 1 << 0,		/* needs timer */
+	INSTRUMENT_BUFFERS	= 1 << 1,		/* needs buffer usage */
+	INSTRUMENT_ALL		= 0x7FFFFFFF
+} InstrumentOption;
+
 typedef struct Instrumentation
 {
 	/* Info about current plan cycle: */
 	bool		running;		/* TRUE if we've completed first tuple */
+	bool		needs_bufusage;	/* TRUE if we need buffer usage */
 	instr_time	starttime;		/* Start time of current iteration of node */
 	instr_time	counter;		/* Accumulated runtime for this node */
 	double		firsttuple;		/* Time for first tuple of this cycle */
 	double		tuplecount;		/* Tuples emitted so far this cycle */
+	BufferUsage	bufusage_start;	/* Buffer usage at start */
 	/* Accumulated statistics across all completed cycles: */
 	double		startup;		/* Total startup time (in seconds) */
 	double		total;			/* Total total time (in seconds) */
 	double		ntuples;		/* Total tuples produced */
 	double		nloops;			/* # of run cycles for this node */
+	BufferUsage	bufusage;		/* Total buffer usage */
 } Instrumentation;
 
-extern Instrumentation *InstrAlloc(int n);
+extern BufferUsage		pgBufferUsage;
+
+extern Instrumentation *InstrAlloc(int n, int instrument_options);
 extern void InstrStartNode(Instrumentation *instr);
 extern void InstrStopNode(Instrumentation *instr, double nTuples);
 extern void InstrEndLoop(Instrumentation *instr);