Revert r1850 as MySQL did not approve the addition.

log for r1850:

Implement this feature request:
http://bugs.mysql.com/30706

* Add a function that returns the number of microseconds since
  epoch - ut_time_us().

* Add (innodb|innobase|srv)_replication_delay MySQL config parameter.

* Add UT_WAIT_FOR() macro that waits for a specified condition to occur
  until a timeout elapses.

* Using all of the above, handle the replication thread specially in
  srv_conc_enter_innodb().

handler/ha_innodb.cc

@@ -7962,12 +7962,6 @@ static MYSQL_SYSVAR_BOOL(use_adaptive_hash_indexes, innobase_use_adaptive_hash_i
   "Enable the InnoDB adaptive hash indexes (enabled by default)",
   NULL, NULL, TRUE);
 
-static MYSQL_SYSVAR_ULONG(replication_delay, srv_replication_delay,
-  PLUGIN_VAR_RQCMDARG,
-  "Replication thread delay (ms) on the slave server if "
-  "innodb_thread_concurrency is reached (0 by default)",
-  NULL, NULL, 0, 0, ~0UL, 0);
-
 static MYSQL_SYSVAR_LONG(additional_mem_pool_size, innobase_additional_mem_pool_size,
   PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
   "Size of a memory pool InnoDB uses to store data dictionary information and other internal data structures.",
@@ -8097,7 +8091,6 @@ static struct st_mysql_sys_var* innobase_system_variables[]= {
   MYSQL_SYSVAR(rollback_on_timeout),
   MYSQL_SYSVAR(stats_on_metadata),
   MYSQL_SYSVAR(use_adaptive_hash_indexes),
-  MYSQL_SYSVAR(replication_delay),
   MYSQL_SYSVAR(status_file),
   MYSQL_SYSVAR(support_xa),
   MYSQL_SYSVAR(sync_spin_loops),

include/srv0srv.h

@@ -136,8 +136,6 @@ extern ulong	srv_max_buf_pool_modified_pct;
 extern ulong	srv_max_purge_lag;
 extern ibool	srv_use_awe;
 extern ibool	srv_use_adaptive_hash_indexes;
-
-extern ulint	srv_replication_delay;
 /*-------------------------------------------*/
 
 extern ulint	srv_n_rows_inserted;

include/ut0ut.h

@@ -17,21 +17,6 @@ Created 1/20/1994 Heikki Tuuri
 
 typedef time_t	ib_time_t;
 
-/*************************************************************************
-Delays execution for at most max_wait_us microseconds or returns earlier
-if cond becomes true; cond is evaluated every 2 ms. */
-
-#define UT_WAIT_FOR(cond, max_wait_us)				\
-do {								\
-	ullint	start_us;					\
-	start_us = ut_time_us(NULL);				\
-	while (!(cond) 						\
-	       && ut_time_us(NULL) - start_us < (max_wait_us)) {\
-								\
-		os_thread_sleep(2000 /* 2 ms */);		\
-	}							\
-} while (0)
-
 /************************************************************
 Gets the high 32 bits in a ulint. That is makes a shift >> 32,
 but since there seem to be compiler bugs in both gcc and Visual C++,
@@ -167,18 +152,6 @@ ut_usectime(
 /*========*/
 	ulint*	sec,	/* out: seconds since the Epoch */
 	ulint*	ms);	/* out: microseconds since the Epoch+*sec */
-
-/**************************************************************
-Returns the number of microseconds since epoch. Similar to
-time(3), the return value is also stored in *tloc, provided
-that tloc is non-NULL. */
-
-ullint
-ut_time_us(
-/*=======*/
-			/* out: us since epoch */
-	ullint*	tloc);	/* out: us since epoch, if non-NULL */
-
 /**************************************************************
 Returns the difference of two times in seconds. */
 

srv/srv0srv.c

@@ -28,7 +28,6 @@ Created 10/8/1995 Heikki Tuuri
 #include "srv0srv.h"
 
 #include "ut0mem.h"
-#include "ut0ut.h"
 #include "os0proc.h"
 #include "mem0mem.h"
 #include "mem0pool.h"
@@ -342,8 +341,6 @@ disable adaptive hash indexes */
 ibool	srv_use_awe			= FALSE;
 ibool	srv_use_adaptive_hash_indexes	= TRUE;
 
-ulint	srv_replication_delay		= 0;
-
 /*-------------------------------------------*/
 ulong	srv_n_spin_wait_rounds	= 20;
 ulong	srv_n_free_tickets_to_enter = 500;
@@ -994,10 +991,11 @@ srv_conc_enter_innodb(
 	if (trx->mysql_thd != NULL
 	    && thd_is_replication_slave_thread(trx->mysql_thd)) {
 
-		UT_WAIT_FOR(srv_conc_n_threads
-			    < (lint)srv_thread_concurrency,
-			    srv_replication_delay * 1000);
-
+		/* TODO Do something more interesting (based on a config
+		parameter). Some users what to give the replication
+		thread very low priority, see http://bugs.mysql.com/25078
+		This can be done by introducing
+		innodb_replication_delay(ms) config parameter */
 		return;
 	}
 

ut/ut0ut.c

@@ -127,31 +127,6 @@ ut_usectime(
 	*ms  = (ulint) tv.tv_usec;
 }
 
-/**************************************************************
-Returns the number of microseconds since epoch. Similar to
-time(3), the return value is also stored in *tloc, provided
-that tloc is non-NULL. */
-
-ullint
-ut_time_us(
-/*=======*/
-			/* out: us since epoch */
-	ullint*	tloc)	/* out: us since epoch, if non-NULL */
-{
-	struct timeval	tv;
-	ullint		us;
-
-	ut_gettimeofday(&tv, NULL);
-
-	us = (ullint) tv.tv_sec * 1000000 + tv.tv_usec;
-
-	if (tloc != NULL) {
-		*tloc = us;
-	}
-
-	return(us);
-}
-
 /**************************************************************
 Returns the difference of two times in seconds. */