Rename I/O timing statistics columns to shared_blk_{read|write}_time

These two counters, defined in BufferUsage to track respectively the
time spent while reading and writing blocks have historically only
tracked data related to shared buffers, when track_io_timing is enabled.

An upcoming patch to add specific counters for local buffers will take
advantage of this rename as it has come up that no data is currently
tracked for local buffers, and tracking local and shared buffers using
the same fields would be inconsistent with the treatment done for temp
buffers.  Renaming the existing fields clarifies what the block type of
each stats field is.

pg_stat_statement is updated to reflect the rename.  No extension
version bump is required as 5a3423ad8ee17 has done one, affecting v17~.

Author: Nazir Bilal Yavuz
Reviewed-by: Robert Haas, Melanie Plageman
Discussion: https://postgr.es/m/CAN55FZ19Ss279mZuqGbuUNxka0iPbLgYuOQXqAKewrjNrp27VA@mail.gmail.com

5 files changed, 79 insertions, 78 deletions

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 13217807eed..d6cf948f384 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -3562,12 +3562,13 @@ show_buffer_usage(ExplainState *es, const BufferUsage *usage, bool planning)
 								 usage->local_blks_written > 0);
 		bool		has_temp = (usage->temp_blks_read > 0 ||
 								usage->temp_blks_written > 0);
-		bool		has_timing = (!INSTR_TIME_IS_ZERO(usage->blk_read_time) ||
-								  !INSTR_TIME_IS_ZERO(usage->blk_write_time));
+		bool		has_shared_timing = (!INSTR_TIME_IS_ZERO(usage->shared_blk_read_time) ||
+										 !INSTR_TIME_IS_ZERO(usage->shared_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_timing ||
+												  has_local || has_temp ||
+												  has_shared_timing ||
 												  has_temp_timing));
 
 		if (show_planning)
@@ -3633,20 +3634,20 @@ show_buffer_usage(ExplainState *es, const BufferUsage *usage, bool planning)
 		}
 
 		/* As above, show only positive counter values. */
-		if (has_timing || has_temp_timing)
+		if (has_shared_timing || has_temp_timing)
 		{
 			ExplainIndentText(es);
 			appendStringInfoString(es->str, "I/O Timings:");
 
-			if (has_timing)
+			if (has_shared_timing)
 			{
-				appendStringInfoString(es->str, " shared/local");
-				if (!INSTR_TIME_IS_ZERO(usage->blk_read_time))
+				appendStringInfoString(es->str, " shared");
+				if (!INSTR_TIME_IS_ZERO(usage->shared_blk_read_time))
 					appendStringInfo(es->str, " read=%0.3f",
-									 INSTR_TIME_GET_MILLISEC(usage->blk_read_time));
-				if (!INSTR_TIME_IS_ZERO(usage->blk_write_time))
+									 INSTR_TIME_GET_MILLISEC(usage->shared_blk_read_time));
+				if (!INSTR_TIME_IS_ZERO(usage->shared_blk_write_time))
 					appendStringInfo(es->str, " write=%0.3f",
-									 INSTR_TIME_GET_MILLISEC(usage->blk_write_time));
+									 INSTR_TIME_GET_MILLISEC(usage->shared_blk_write_time));
 				if (has_temp_timing)
 					appendStringInfoChar(es->str, ',');
 			}
@@ -3690,11 +3691,11 @@ show_buffer_usage(ExplainState *es, const BufferUsage *usage, bool planning)
 							   usage->temp_blks_written, es);
 		if (track_io_timing)
 		{
-			ExplainPropertyFloat("I/O Read Time", "ms",
-								 INSTR_TIME_GET_MILLISEC(usage->blk_read_time),
+			ExplainPropertyFloat("Shared I/O Read Time", "ms",
+								 INSTR_TIME_GET_MILLISEC(usage->shared_blk_read_time),
 								 3, es);
-			ExplainPropertyFloat("I/O Write Time", "ms",
-								 INSTR_TIME_GET_MILLISEC(usage->blk_write_time),
+			ExplainPropertyFloat("Shared I/O Write Time", "ms",
+								 INSTR_TIME_GET_MILLISEC(usage->shared_blk_write_time),
 								 3, es);
 			ExplainPropertyFloat("Temp I/O Read Time", "ms",
 								 INSTR_TIME_GET_MILLISEC(usage->temp_blk_read_time),
diff --git a/src/backend/executor/instrument.c b/src/backend/executor/instrument.c
index ee78a5749d2..ef2a24b7cfb 100644
--- a/src/backend/executor/instrument.c
+++ b/src/backend/executor/instrument.c
@@ -235,8 +235,8 @@ BufferUsageAdd(BufferUsage *dst, const BufferUsage *add)
 	dst->local_blks_written += add->local_blks_written;
 	dst->temp_blks_read += add->temp_blks_read;
 	dst->temp_blks_written += add->temp_blks_written;
-	INSTR_TIME_ADD(dst->blk_read_time, add->blk_read_time);
-	INSTR_TIME_ADD(dst->blk_write_time, add->blk_write_time);
+	INSTR_TIME_ADD(dst->shared_blk_read_time, add->shared_blk_read_time);
+	INSTR_TIME_ADD(dst->shared_blk_write_time, add->shared_blk_write_time);
 	INSTR_TIME_ADD(dst->temp_blk_read_time, add->temp_blk_read_time);
 	INSTR_TIME_ADD(dst->temp_blk_write_time, add->temp_blk_write_time);
 }
@@ -257,10 +257,10 @@ BufferUsageAccumDiff(BufferUsage *dst,
 	dst->local_blks_written += add->local_blks_written - sub->local_blks_written;
 	dst->temp_blks_read += add->temp_blks_read - sub->temp_blks_read;
 	dst->temp_blks_written += add->temp_blks_written - sub->temp_blks_written;
-	INSTR_TIME_ACCUM_DIFF(dst->blk_read_time,
-						  add->blk_read_time, sub->blk_read_time);
-	INSTR_TIME_ACCUM_DIFF(dst->blk_write_time,
-						  add->blk_write_time, sub->blk_write_time);
+	INSTR_TIME_ACCUM_DIFF(dst->shared_blk_read_time,
+						  add->shared_blk_read_time, sub->shared_blk_read_time);
+	INSTR_TIME_ACCUM_DIFF(dst->shared_blk_write_time,
+						  add->shared_blk_write_time, sub->shared_blk_write_time);
 	INSTR_TIME_ACCUM_DIFF(dst->temp_blk_read_time,
 						  add->temp_blk_read_time, sub->temp_blk_read_time);
 	INSTR_TIME_ACCUM_DIFF(dst->temp_blk_write_time,
diff --git a/src/backend/utils/activity/pgstat_io.c b/src/backend/utils/activity/pgstat_io.c
index 8ec86701997..297cfc15fb9 100644
--- a/src/backend/utils/activity/pgstat_io.c
+++ b/src/backend/utils/activity/pgstat_io.c
@@ -123,13 +123,13 @@ pgstat_count_io_op_time(IOObject io_object, IOContext io_context, IOOp io_op,
 		{
 			pgstat_count_buffer_write_time(INSTR_TIME_GET_MICROSEC(io_time));
 			if (io_object == IOOBJECT_RELATION)
-				INSTR_TIME_ADD(pgBufferUsage.blk_write_time, io_time);
+				INSTR_TIME_ADD(pgBufferUsage.shared_blk_write_time, io_time);
 		}
 		else if (io_op == IOOP_READ)
 		{
 			pgstat_count_buffer_read_time(INSTR_TIME_GET_MICROSEC(io_time));
 			if (io_object == IOOBJECT_RELATION)
-				INSTR_TIME_ADD(pgBufferUsage.blk_read_time, io_time);
+				INSTR_TIME_ADD(pgBufferUsage.shared_blk_read_time, io_time);
 		}
 
 		INSTR_TIME_ADD(PendingIOStats.pending_times[io_object][io_context][io_op],
diff --git a/src/include/executor/instrument.h b/src/include/executor/instrument.h
index 87e5e2183bd..14c3e3f656c 100644
--- a/src/include/executor/instrument.h
+++ b/src/include/executor/instrument.h
@@ -33,8 +33,8 @@ typedef struct BufferUsage
 	int64		local_blks_written; /* # of local disk blocks written */
 	int64		temp_blks_read; /* # of temp blocks read */
 	int64		temp_blks_written;	/* # of temp blocks written */
-	instr_time	blk_read_time;	/* time spent reading blocks */
-	instr_time	blk_write_time; /* time spent writing blocks */
+	instr_time	shared_blk_read_time;	/* time spent reading shared blocks */
+	instr_time	shared_blk_write_time;	/* time spent writing shared blocks */
 	instr_time	temp_blk_read_time; /* time spent reading temp blocks */
 	instr_time	temp_blk_write_time;	/* time spent writing temp blocks */
 } BufferUsage;
diff --git a/src/test/regress/expected/explain.out b/src/test/regress/expected/explain.out
index 1aca77491b9..a101886299e 100644
--- a/src/test/regress/expected/explain.out
+++ b/src/test/regress/expected/explain.out
@@ -230,60 +230,60 @@ select explain_filter('explain (buffers, format json) select * from int8_tbl i8'
 -- but always set in JSON format, so check them only in this case.
 set track_io_timing = on;
 select explain_filter('explain (analyze, buffers, format json) select * from int8_tbl i8');
-           explain_filter           
-------------------------------------
- [                                 +
-   {                               +
-     "Plan": {                     +
-       "Node Type": "Seq Scan",    +
-       "Parallel Aware": false,    +
-       "Async Capable": false,     +
-       "Relation Name": "int8_tbl",+
-       "Alias": "i8",              +
-       "Startup Cost": N.N,        +
-       "Total Cost": N.N,          +
-       "Plan Rows": N,             +
-       "Plan Width": N,            +
-       "Actual Startup Time": N.N, +
-       "Actual Total Time": N.N,   +
-       "Actual Rows": N,           +
-       "Actual Loops": N,          +
-       "Shared Hit Blocks": N,     +
-       "Shared Read Blocks": N,    +
-       "Shared Dirtied Blocks": N, +
-       "Shared Written Blocks": N, +
-       "Local Hit Blocks": N,      +
-       "Local Read Blocks": N,     +
-       "Local Dirtied Blocks": N,  +
-       "Local Written Blocks": N,  +
-       "Temp Read Blocks": N,      +
-       "Temp Written Blocks": N,   +
-       "I/O Read Time": N.N,       +
-       "I/O Write Time": N.N,      +
-       "Temp I/O Read Time": N.N,  +
-       "Temp I/O Write Time": N.N  +
-     },                            +
-     "Planning": {                 +
-       "Shared Hit Blocks": N,     +
-       "Shared Read Blocks": N,    +
-       "Shared Dirtied Blocks": N, +
-       "Shared Written Blocks": N, +
-       "Local Hit Blocks": N,      +
-       "Local Read Blocks": N,     +
-       "Local Dirtied Blocks": N,  +
-       "Local Written Blocks": N,  +
-       "Temp Read Blocks": N,      +
-       "Temp Written Blocks": N,   +
-       "I/O Read Time": N.N,       +
-       "I/O Write Time": N.N,      +
-       "Temp I/O Read Time": N.N,  +
-       "Temp I/O Write Time": N.N  +
-     },                            +
-     "Planning Time": N.N,         +
-     "Triggers": [                 +
-     ],                            +
-     "Execution Time": N.N         +
-   }                               +
+           explain_filter            
+-------------------------------------
+ [                                  +
+   {                                +
+     "Plan": {                      +
+       "Node Type": "Seq Scan",     +
+       "Parallel Aware": false,     +
+       "Async Capable": false,      +
+       "Relation Name": "int8_tbl", +
+       "Alias": "i8",               +
+       "Startup Cost": N.N,         +
+       "Total Cost": N.N,           +
+       "Plan Rows": N,              +
+       "Plan Width": N,             +
+       "Actual Startup Time": N.N,  +
+       "Actual Total Time": N.N,    +
+       "Actual Rows": N,            +
+       "Actual Loops": N,           +
+       "Shared Hit Blocks": N,      +
+       "Shared Read Blocks": N,     +
+       "Shared Dirtied Blocks": N,  +
+       "Shared Written Blocks": N,  +
+       "Local Hit Blocks": N,       +
+       "Local Read Blocks": N,      +
+       "Local Dirtied Blocks": N,   +
+       "Local Written Blocks": N,   +
+       "Temp Read Blocks": N,       +
+       "Temp Written Blocks": N,    +
+       "Shared I/O Read Time": N.N, +
+       "Shared I/O Write Time": N.N,+
+       "Temp I/O Read Time": N.N,   +
+       "Temp I/O Write Time": N.N   +
+     },                             +
+     "Planning": {                  +
+       "Shared Hit Blocks": N,      +
+       "Shared Read Blocks": N,     +
+       "Shared Dirtied Blocks": N,  +
+       "Shared Written Blocks": N,  +
+       "Local Hit Blocks": N,       +
+       "Local Read Blocks": N,      +
+       "Local Dirtied Blocks": N,   +
+       "Local Written Blocks": N,   +
+       "Temp Read Blocks": N,       +
+       "Temp Written Blocks": N,    +
+       "Shared I/O Read Time": N.N, +
+       "Shared I/O Write Time": N.N,+
+       "Temp I/O Read Time": N.N,   +
+       "Temp I/O Write Time": N.N   +
+     },                             +
+     "Planning Time": N.N,          +
+     "Triggers": [                  +
+     ],                             +
+     "Execution Time": N.N          +
+   }                                +
  ]
 (1 row)