Remove the debug variables innodb_purge_stop_now, innodb_purge_run_now

The InnoDB purge subsystem can be best stopped by opening a read view,
for example by START TRANSACTION WITH CONSISTENT SNAPSHOT.

To ensure that everything is purged, use wait_all_purged.inc,
which waits for the History list length in SHOW ENGINE INNODB STATUS
to reach 0. Setting innodb_purge_run_now never guaranteed this.

mysql-test/suite/innodb/r/innodb-wl5522-debug.result

@@ -494,7 +494,9 @@ c4 VARCHAR(2048),
 INDEX idx1(c2),
 INDEX idx2(c3(512)),
 INDEX idx3(c4(512))) Engine=InnoDB;
-SET GLOBAL INNODB_PURGE_STOP_NOW=ON;
+connect  purge_control,localhost,root;
+START TRANSACTION WITH CONSISTENT SNAPSHOT;
+connection default;
 SET GLOBAL innodb_disable_background_merge=ON;
 SET GLOBAL innodb_monitor_reset = ibuf_merges;
 SET GLOBAL innodb_monitor_reset = ibuf_merges_insert;
@@ -659,7 +661,10 @@ FROM information_schema.innodb_metrics
 WHERE name = 'ibuf_merges_inserts' AND count > 0;
 name
 SET GLOBAL innodb_disable_background_merge=OFF;
-SET GLOBAL INNODB_PURGE_RUN_NOW=ON;
+connection purge_control;
+COMMIT;
+disconnect purge_control;
+connection default;
 DROP TABLE test_wl5522.t1;
 CREATE TABLE test_wl5522.t1 (
 c1 BIGINT NOT NULL AUTO_INCREMENT PRIMARY KEY,

mysql-test/suite/innodb/t/innodb-wl5522-debug.test

@@ -1055,7 +1055,9 @@ CREATE TABLE test_wl5522.t1 (
 	INDEX idx3(c4(512))) Engine=InnoDB;
 
 # Stop purge so that it doesn't remove the delete marked entries.
-SET GLOBAL INNODB_PURGE_STOP_NOW=ON;
+connect (purge_control,localhost,root);
+START TRANSACTION WITH CONSISTENT SNAPSHOT;
+connection default;
 
 # Disable change buffer merge from the master thread, additionally
 # enable aggressive flushing so that more changes are buffered.
@@ -1125,7 +1127,10 @@ SELECT name
 SET GLOBAL innodb_disable_background_merge=OFF;
 
 # Enable normal operation
-SET GLOBAL INNODB_PURGE_RUN_NOW=ON;
+connection purge_control;
+COMMIT;
+disconnect purge_control;
+connection default;
 
 DROP TABLE test_wl5522.t1;
 

mysql-test/suite/innodb_zip/r/wl5522_debug_zip.result

@@ -123,7 +123,9 @@ INDEX idx1(c2),
 INDEX idx2(c3(512)),
 INDEX idx3(c4(512))) Engine=InnoDB
 ROW_FORMAT=COMPRESSED;
-SET GLOBAL INNODB_PURGE_STOP_NOW=ON;
+connect  purge_control,localhost,root;
+START TRANSACTION WITH CONSISTENT SNAPSHOT;
+connection default;
 SET GLOBAL innodb_disable_background_merge=ON;
 SET GLOBAL innodb_monitor_reset = ibuf_merges;
 SET GLOBAL innodb_monitor_reset = ibuf_merges_insert;
@@ -288,7 +290,10 @@ FROM information_schema.innodb_metrics
 WHERE name = 'ibuf_merges_inserts' AND count > 0;
 name
 SET GLOBAL innodb_disable_background_merge=OFF;
-SET GLOBAL INNODB_PURGE_RUN_NOW=ON;
+connection purge_control;
+COMMIT;
+disconnect purge_control;
+connection default;
 DROP TABLE test_wl5522.t1;
 CREATE TABLE test_wl5522.t1 (
 c1 BIGINT NOT NULL AUTO_INCREMENT PRIMARY KEY,

mysql-test/suite/innodb_zip/t/wl5522_debug_zip.test

@@ -321,7 +321,9 @@ CREATE TABLE test_wl5522.t1 (
         ROW_FORMAT=COMPRESSED;
 
 # Stop purge so that it doesn't remove the delete marked entries.
-SET GLOBAL INNODB_PURGE_STOP_NOW=ON;
+connect (purge_control,localhost,root);
+START TRANSACTION WITH CONSISTENT SNAPSHOT;
+connection default;
 
 # Disable change buffer merge from the master thread, additionally
 # enable aggressive flushing so that more changes are buffered.
@@ -391,7 +393,10 @@ SELECT name
 SET GLOBAL innodb_disable_background_merge=OFF;
 
 # Enable normal operation
-SET GLOBAL INNODB_PURGE_RUN_NOW=ON;
+connection purge_control;
+COMMIT;
+disconnect purge_control;
+connection default;
 
 DROP TABLE test_wl5522.t1;
 

mysql-test/suite/sys_vars/r/sysvars_innodb.result

@@ -2274,34 +2274,6 @@ NUMERIC_BLOCK_SIZE	0
 ENUM_VALUE_LIST	NULL
 READ_ONLY	NO
 COMMAND_LINE_ARGUMENT	OPTIONAL
-VARIABLE_NAME	INNODB_PURGE_RUN_NOW
-SESSION_VALUE	NULL
-GLOBAL_VALUE	OFF
-GLOBAL_VALUE_ORIGIN	COMPILE-TIME
-DEFAULT_VALUE	OFF
-VARIABLE_SCOPE	GLOBAL
-VARIABLE_TYPE	BOOLEAN
-VARIABLE_COMMENT	Set purge state to RUN
-NUMERIC_MIN_VALUE	NULL
-NUMERIC_MAX_VALUE	NULL
-NUMERIC_BLOCK_SIZE	NULL
-ENUM_VALUE_LIST	OFF,ON
-READ_ONLY	NO
-COMMAND_LINE_ARGUMENT	OPTIONAL
-VARIABLE_NAME	INNODB_PURGE_STOP_NOW
-SESSION_VALUE	NULL
-GLOBAL_VALUE	OFF
-GLOBAL_VALUE_ORIGIN	COMPILE-TIME
-DEFAULT_VALUE	OFF
-VARIABLE_SCOPE	GLOBAL
-VARIABLE_TYPE	BOOLEAN
-VARIABLE_COMMENT	Set purge state to STOP
-NUMERIC_MIN_VALUE	NULL
-NUMERIC_MAX_VALUE	NULL
-NUMERIC_BLOCK_SIZE	NULL
-ENUM_VALUE_LIST	OFF,ON
-READ_ONLY	NO
-COMMAND_LINE_ARGUMENT	OPTIONAL
 VARIABLE_NAME	INNODB_PURGE_THREADS
 SESSION_VALUE	NULL
 GLOBAL_VALUE	4

storage/innobase/handler/ha_innodb.cc

@@ -19750,8 +19750,6 @@ innobase_fts_find_ranking(FT_INFO* fts_hdl, uchar*, uint)
 
 #ifdef UNIV_DEBUG
 static my_bool	innodb_background_drop_list_empty = TRUE;
-static my_bool	innodb_purge_run_now = TRUE;
-static my_bool	innodb_purge_stop_now = TRUE;
 static my_bool	innodb_log_checkpoint_now = TRUE;
 static my_bool	innodb_buf_flush_list_now = TRUE;
 static uint	innodb_merge_threshold_set_all_debug
@@ -19775,52 +19773,6 @@ wait_background_drop_list_empty(
 	row_wait_for_background_drop_list_empty();
 }
 
-/****************************************************************//**
-Set the purge state to RUN. If purge is disabled then it
-is a no-op. This function is registered as a callback with MySQL. */
-static
-void
-purge_run_now_set(
-/*==============*/
-	THD*				thd	/*!< in: thread handle */
-					MY_ATTRIBUTE((unused)),
-	struct st_mysql_sys_var*	var	/*!< in: pointer to system
-						variable */
-					MY_ATTRIBUTE((unused)),
-	void*				var_ptr	/*!< out: where the formal
-						string goes */
-					MY_ATTRIBUTE((unused)),
-	const void*			save)	/*!< in: immediate result from
-						check function */
-{
-	if (*(my_bool*) save && trx_purge_state() != PURGE_STATE_DISABLED) {
-		trx_purge_run();
-	}
-}
-
-/****************************************************************//**
-Set the purge state to STOP. If purge is disabled then it
-is a no-op. This function is registered as a callback with MySQL. */
-static
-void
-purge_stop_now_set(
-/*===============*/
-	THD*				thd	/*!< in: thread handle */
-					MY_ATTRIBUTE((unused)),
-	struct st_mysql_sys_var*	var	/*!< in: pointer to system
-						variable */
-					MY_ATTRIBUTE((unused)),
-	void*				var_ptr	/*!< out: where the formal
-						string goes */
-					MY_ATTRIBUTE((unused)),
-	const void*			save)	/*!< in: immediate result from
-						check function */
-{
-	if (*(my_bool*) save && trx_purge_state() != PURGE_STATE_DISABLED) {
-		trx_purge_stop();
-	}
-}
-
 /****************************************************************//**
 Force innodb to checkpoint. */
 static
@@ -20629,16 +20581,6 @@ static MYSQL_SYSVAR_BOOL(background_drop_list_empty,
   "Wait for the background drop list to become empty",
   NULL, wait_background_drop_list_empty, FALSE);
 
-static MYSQL_SYSVAR_BOOL(purge_run_now, innodb_purge_run_now,
-  PLUGIN_VAR_OPCMDARG,
-  "Set purge state to RUN",
-  NULL, purge_run_now_set, FALSE);
-
-static MYSQL_SYSVAR_BOOL(purge_stop_now, innodb_purge_stop_now,
-  PLUGIN_VAR_OPCMDARG,
-  "Set purge state to STOP",
-  NULL, purge_stop_now_set, FALSE);
-
 static MYSQL_SYSVAR_BOOL(log_checkpoint_now, innodb_log_checkpoint_now,
   PLUGIN_VAR_OPCMDARG,
   "Force checkpoint now",
@@ -21912,8 +21854,6 @@ static struct st_mysql_sys_var* innobase_system_variables[]= {
   MYSQL_SYSVAR(purge_batch_size),
 #ifdef UNIV_DEBUG
   MYSQL_SYSVAR(background_drop_list_empty),
-  MYSQL_SYSVAR(purge_run_now),
-  MYSQL_SYSVAR(purge_stop_now),
   MYSQL_SYSVAR(log_checkpoint_now),
   MYSQL_SYSVAR(buf_flush_list_now),
   MYSQL_SYSVAR(merge_threshold_set_all_debug),