MDEV-12345 Performance : replace calls to clock() inside trx_start_lo…

…w() by THD::start_utime

sql/sql_class.cc

@@ -4534,6 +4534,15 @@ extern "C" int thd_rpl_is_parallel(const MYSQL_THD thd)
   return thd->rgi_slave && thd->rgi_slave->is_parallel_exec;
 }
 
+
+/* Returns high resolution timestamp for the start
+  of the current query. */
+extern "C" unsigned long long thd_start_utime(const MYSQL_THD thd)
+{
+  return thd->start_utime;
+}
+
+
 /*
   This function can optionally be called to check if thd_report_wait_for()
   needs to be called for waits done by a given transaction.

storage/innobase/handler/ha_innodb.cc

@@ -1705,6 +1705,15 @@ thd_has_edited_nontrans_tables(
 	return((ibool) thd_non_transactional_update(thd));
 }
 
+/* Return high resolution timestamp for the start of the current query */
+UNIV_INTERN
+ib_uint64_t
+thd_query_start_micro(
+	const THD*	thd)	/*!< in: thread handle */
+{
+	return thd_start_utime(thd);
+}
+
 /******************************************************************//**
 Returns true if the thread is executing a SELECT statement.
 @return	true if thd is executing SELECT */

storage/innobase/handler/ha_innodb.h

@@ -420,6 +420,15 @@ int thd_slave_thread(const MYSQL_THD thd);
 */
 int thd_non_transactional_update(const MYSQL_THD thd);
 
+/**
+  Get high resolution timestamp for the current query start time.
+  The timestamp is not anchored to any specific point in time,
+  but can be used for comparison.
+
+  @retval timestamp in microseconds precision
+*/
+unsigned long long thd_start_utime(const MYSQL_THD thd);
+
 /**
   Get the user thread's binary logging format
   @param thd  user thread

storage/innobase/include/ha_prototypes.h

@@ -150,6 +150,13 @@ thd_has_edited_nontrans_tables(
 /*===========================*/
 	THD*	thd);	/*!< in: thread handle */
 
+/**
+Get high resolution timestamp for the current query start time.
+
+@retval timestamp in microseconds precision
+*/
+unsigned long long thd_query_start_micro(const MYSQL_THD thd);
+
 /*************************************************************//**
 Prints info of a THD object (== user session thread) to the given file. */
 UNIV_INTERN

storage/innobase/include/trx0trx.h

@@ -849,7 +849,7 @@ struct trx_t{
 
 	time_t		start_time;	/*!< time the trx state last time became
 					TRX_STATE_ACTIVE */
-	clock_t		start_time_micro;	/*!< start time of transaction in
+	ib_uint64_t	start_time_micro;	/*!< start time of transaction in
 					microseconds */
 	trx_id_t	id;		/*!< transaction id */
 	XID		xid;		/*!< X/Open XA transaction

storage/innobase/trx/trx0trx.cc

@@ -923,7 +923,8 @@ trx_start_low(
 
 	trx->start_time = ut_time();
 
-	trx->start_time_micro = clock();
+	trx->start_time_micro =
+		trx->mysql_thd ? thd_query_start_micro(trx->mysql_thd) : 0;
 
 	MONITOR_INC(MONITOR_TRX_ACTIVE);
 }

storage/xtradb/handler/ha_innodb.cc

@@ -1981,6 +1981,15 @@ thd_has_edited_nontrans_tables(
 	return((ibool) thd_non_transactional_update(thd));
 }
 
+/* Return high resolution timestamp for the start of the current query */
+UNIV_INTERN
+ib_uint64_t
+thd_query_start_micro(
+	const THD*	thd)	/*!< in: thread handle */
+{
+	return thd_start_utime(thd);
+}
+
 /******************************************************************//**
 Returns true if the thread is executing a SELECT statement.
 @return	true if thd is executing SELECT */

storage/xtradb/handler/ha_innodb.h

@@ -427,6 +427,15 @@ int thd_slave_thread(const MYSQL_THD thd);
 */
 int thd_non_transactional_update(const MYSQL_THD thd);
 
+/**
+  Get high resolution timestamp for the current query start time.
+  The timestamp is not anchored to any specific point in time,
+  but can be used for comparison.
+
+  @retval timestamp in microseconds precision
+*/
+unsigned long long thd_start_utime(const MYSQL_THD thd);
+
 /**
   Get the user thread's binary logging format
   @param thd  user thread

storage/xtradb/include/ha_prototypes.h

@@ -157,6 +157,13 @@ thd_has_edited_nontrans_tables(
 /*===========================*/
 	THD*	thd);	/*!< in: thread handle */
 
+/**
+Get high resolution timestamp for the current query start time.
+
+@retval timestamp in microseconds precision
+*/
+unsigned long long thd_query_start_micro(const MYSQL_THD thd);
+
 /*************************************************************//**
 Prints info of a THD object (== user session thread) to the given file. */
 UNIV_INTERN

storage/xtradb/include/trx0trx.h

@@ -882,7 +882,7 @@ struct trx_t{
 
 	time_t		start_time;	/*!< time the trx state last time became
 					TRX_STATE_ACTIVE */
-	clock_t		start_time_micro;	/*!< start time of transaction in
+	ib_uint64_t	start_time_micro;	/*!< start time of transaction in
 					microseconds */
 	trx_id_t	id;		/*!< transaction id */
 	XID		xid;		/*!< X/Open XA transaction

storage/xtradb/trx/trx0trx.cc

@@ -1121,7 +1121,8 @@ trx_start_low(
 
 	trx->start_time = ut_time();
 
-	trx->start_time_micro = clock();
+	trx->start_time_micro =
+		trx->mysql_thd ? thd_query_start_micro(trx->mysql_thd) : 0;
 
 	MONITOR_INC(MONITOR_TRX_ACTIVE);
 }