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.

1 files changed, 26 insertions, 2 deletions

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);