Converge all SQL-level statistics timing values to float8 milliseconds.

This patch adjusts the core statistics views to match the decision already
taken for pg_stat_statements, that values representing elapsed time should
be represented as float8 and measured in milliseconds.  By using float8,
we are no longer tied to a specific maximum precision of timing data.
(Internally, it's still microseconds, but we could now change that without
needing changes at the SQL level.)

The columns affected are
pg_stat_bgwriter.checkpoint_write_time
pg_stat_bgwriter.checkpoint_sync_time
pg_stat_database.blk_read_time
pg_stat_database.blk_write_time
pg_stat_user_functions.total_time
pg_stat_user_functions.self_time
pg_stat_xact_user_functions.total_time
pg_stat_xact_user_functions.self_time

The first four of these are new in 9.2, so there is no compatibility issue
from changing them.  The others require a release note comment that they
are now double precision (and can show a fractional part) rather than
bigint as before; also their underlying statistics functions now match
the column definitions, instead of returning bigint microseconds.

1 files changed, 15 insertions, 15 deletions

diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 04f7c1aa711..ac971abb184 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -848,8 +848,8 @@ pgstat_send_funcstats(void)
 		m_ent = &msg.m_entry[msg.m_nentries];
 		m_ent->f_id = entry->f_id;
 		m_ent->f_numcalls = entry->f_counts.f_numcalls;
-		m_ent->f_time = INSTR_TIME_GET_MICROSEC(entry->f_counts.f_time);
-		m_ent->f_time_self = INSTR_TIME_GET_MICROSEC(entry->f_counts.f_time_self);
+		m_ent->f_total_time = INSTR_TIME_GET_MICROSEC(entry->f_counts.f_total_time);
+		m_ent->f_self_time = INSTR_TIME_GET_MICROSEC(entry->f_counts.f_self_time);
 
 		if (++msg.m_nentries >= PGSTAT_NUM_FUNCENTRIES)
 		{
@@ -1467,7 +1467,7 @@ pgstat_init_function_usage(FunctionCallInfoData *fcinfo,
 	fcu->fs = &htabent->f_counts;
 
 	/* save stats for this function, later used to compensate for recursion */
-	fcu->save_f_time = htabent->f_counts.f_time;
+	fcu->save_f_total_time = htabent->f_counts.f_total_time;
 
 	/* save current backend-wide total time */
 	fcu->save_total = total_func_time;
@@ -1528,19 +1528,19 @@ pgstat_end_function_usage(PgStat_FunctionCallUsage *fcu, bool finalize)
 	INSTR_TIME_ADD(total_func_time, f_self);
 
 	/*
-	 * Compute the new total f_time as the total elapsed time added to the
-	 * pre-call value of f_time.  This is necessary to avoid double-counting
-	 * any time taken by recursive calls of myself.  (We do not need any
-	 * similar kluge for self time, since that already excludes any recursive
-	 * calls.)
+	 * Compute the new f_total_time as the total elapsed time added to the
+	 * pre-call value of f_total_time.  This is necessary to avoid
+	 * double-counting any time taken by recursive calls of myself.  (We do
+	 * not need any similar kluge for self time, since that already excludes
+	 * any recursive calls.)
 	 */
-	INSTR_TIME_ADD(f_total, fcu->save_f_time);
+	INSTR_TIME_ADD(f_total, fcu->save_f_total_time);
 
 	/* update counters in function stats table */
 	if (finalize)
 		fs->f_numcalls++;
-	fs->f_time = f_total;
-	INSTR_TIME_ADD(fs->f_time_self, f_self);
+	fs->f_total_time = f_total;
+	INSTR_TIME_ADD(fs->f_self_time, f_self);
 
 	/* indicate that we have something to send */
 	have_function_stats = true;
@@ -4573,8 +4573,8 @@ pgstat_recv_funcstat(PgStat_MsgFuncstat *msg, int len)
 			 * we just got.
 			 */
 			funcentry->f_numcalls = funcmsg->f_numcalls;
-			funcentry->f_time = funcmsg->f_time;
-			funcentry->f_time_self = funcmsg->f_time_self;
+			funcentry->f_total_time = funcmsg->f_total_time;
+			funcentry->f_self_time = funcmsg->f_self_time;
 		}
 		else
 		{
@@ -4582,8 +4582,8 @@ pgstat_recv_funcstat(PgStat_MsgFuncstat *msg, int len)
 			 * Otherwise add the values to the existing entry.
 			 */
 			funcentry->f_numcalls += funcmsg->f_numcalls;
-			funcentry->f_time += funcmsg->f_time;
-			funcentry->f_time_self += funcmsg->f_time_self;
+			funcentry->f_total_time += funcmsg->f_total_time;
+			funcentry->f_self_time += funcmsg->f_self_time;
 		}
 	}
 }