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MDEV-30658 lock_row_lock_current_waits counter in information_schema.innodb_metrics may become negative

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MONITOR_OVLD_ROW_LOCK_CURRENT_WAIT monitor should has
MONITOR_DISPLAY_CURRENT flag set in its definition, as it shows the
current state and does not accumulate anything.

Reviewed by: Marko Mäkelä
This commit is contained in:
Vlad Lesin
2023-10-03 20:07:39 +03:00
parent 422774b40a
commit 96ae37abc5
5 changed files with 133 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
mysql-test/suite/innodb/r/innodb_skip_innodb_is_tables.result
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@ -50,7 +50,7 @@ lock_rec_locks lock 0 NULL NULL NULL 0 NULL NULL NULL NULL NULL NULL NULL disabl
lock_table_lock_created lock 0 NULL NULL NULL 0 NULL NULL NULL NULL NULL NULL NULL disabled counter Number of table locks created
lock_table_lock_removed lock 0 NULL NULL NULL 0 NULL NULL NULL NULL NULL NULL NULL disabled counter Number of table locks removed from the lock queue
lock_table_locks lock 0 NULL NULL NULL 0 NULL NULL NULL NULL NULL NULL NULL disabled counter Current number of table locks on tables
lock_row_lock_current_waits lock 0 NULL NULL NULL 0 NULL NULL NULL NULL NULL NULL NULL disabled status_counter Number of row locks currently being waited for (innodb_row_lock_current_waits)
lock_row_lock_current_waits lock 0 NULL NULL NULL 0 NULL NULL NULL NULL NULL NULL NULL disabled value Number of row locks currently being waited for (innodb_row_lock_current_waits)
lock_row_lock_time lock 0 NULL NULL NULL 0 NULL NULL NULL NULL NULL NULL NULL disabled status_counter Time spent in acquiring row locks, in milliseconds (innodb_row_lock_time)
lock_row_lock_time_max lock 0 NULL NULL NULL 0 NULL NULL NULL NULL NULL NULL NULL disabled value The maximum time to acquire a row lock, in milliseconds (innodb_row_lock_time_max)
lock_row_lock_waits lock 0 NULL NULL NULL 0 NULL NULL NULL NULL NULL NULL NULL disabled status_counter Number of times a row lock had to be waited for (innodb_row_lock_waits)

54
mysql-test/suite/innodb/r/mon_lock_wait_current_count.result Normal file
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@ -0,0 +1,54 @@
connect prevent_purge,localhost,root,,;
START TRANSACTION WITH CONSISTENT SNAPSHOT;
connection default;
SET GLOBAL innodb_monitor_disable='all';
SET GLOBAL innodb_monitor_enable='lock_row_lock_current_waits';
CREATE TABLE `t` (a INT PRIMARY KEY) engine=InnoDB STATS_PERSISTENT=0;
INSERT INTO t VALUES (5);
SELECT name, count FROM information_schema.innodb_metrics
WHERE name ='lock_row_lock_current_waits';
name count
lock_row_lock_current_waits 0
connect con1,localhost,root,,;
BEGIN;
SELECT * FROM t FOR UPDATE;
a
5
connect con2,localhost,root,,;
SET DEBUG_SYNC="lock_wait_before_suspend SIGNAL blocked WAIT_FOR cont";
BEGIN;
SELECT * FROM t FOR UPDATE;
connection default;
SET DEBUG_SYNC="now WAIT_FOR blocked";
SELECT name, count FROM information_schema.innodb_metrics
WHERE name ='lock_row_lock_current_waits';
name count
lock_row_lock_current_waits 1
SET GLOBAL innodb_monitor_disable='lock_row_lock_current_waits';
SET GLOBAL innodb_monitor_reset_all='lock_row_lock_current_waits';
SET GLOBAL innodb_monitor_enable='lock_row_lock_current_waits';
SELECT name, count FROM information_schema.innodb_metrics
WHERE name ='lock_row_lock_current_waits';
name count
lock_row_lock_current_waits 1
SET DEBUG_SYNC="now SIGNAL cont";
disconnect con1;
connection con2;
a
5
COMMIT;
disconnect con2;
connection default;
SET DEBUG_SYNC="reset";
SELECT name, count FROM information_schema.innodb_metrics
WHERE name ='lock_row_lock_current_waits';
name count
lock_row_lock_current_waits 0
DROP TABLE `t`;
SET GLOBAL innodb_monitor_disable='lock_row_lock_current_waits';
SET GLOBAL innodb_monitor_reset_all='lock_row_lock_current_waits';
SET GLOBAL innodb_monitor_enable='lock_row_lock_current_waits';
SET GLOBAL innodb_monitor_disable=default;
SET GLOBAL innodb_monitor_reset_all=default;
SET GLOBAL innodb_monitor_enable=default;
disconnect prevent_purge;

76
mysql-test/suite/innodb/t/mon_lock_wait_current_count.test Normal file
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@ -0,0 +1,76 @@
# Check if lock_row_lock_current_waits counter in
# information_schema.innodb_metrics does not become negative after disabling,
# resetting and enabling.
--source include/have_innodb.inc
--source include/have_debug.inc
--source include/count_sessions.inc
--connect (prevent_purge,localhost,root,,)
START TRANSACTION WITH CONSISTENT SNAPSHOT;
--connection default
SET GLOBAL innodb_monitor_disable='all';
SET GLOBAL innodb_monitor_enable='lock_row_lock_current_waits';
CREATE TABLE `t` (a INT PRIMARY KEY) engine=InnoDB STATS_PERSISTENT=0;
INSERT INTO t VALUES (5);
SELECT name, count FROM information_schema.innodb_metrics
WHERE name ='lock_row_lock_current_waits';
--connect (con1,localhost,root,,)
BEGIN;
SELECT * FROM t FOR UPDATE;
--connect (con2,localhost,root,,)
SET DEBUG_SYNC="lock_wait_before_suspend SIGNAL blocked WAIT_FOR cont";
BEGIN;
--send SELECT * FROM t FOR UPDATE
--connection default
SET DEBUG_SYNC="now WAIT_FOR blocked";
SELECT name, count FROM information_schema.innodb_metrics
WHERE name ='lock_row_lock_current_waits';
SET GLOBAL innodb_monitor_disable='lock_row_lock_current_waits';
SET GLOBAL innodb_monitor_reset_all='lock_row_lock_current_waits';
SET GLOBAL innodb_monitor_enable='lock_row_lock_current_waits';
######################################
# Equals to zero if the bug is not fixed, as MONITOR_DISPLAY_CURRENT is not
# set for this counter and its value is reset during previous
# "SET GLOBAL innodb_monitor_reset_all='lock_row_lock_current_waits'" execution.
#####
SELECT name, count FROM information_schema.innodb_metrics
WHERE name ='lock_row_lock_current_waits';
SET DEBUG_SYNC="now SIGNAL cont";
--disconnect con1
--connection con2
--reap
COMMIT;
--disconnect con2
--connection default
SET DEBUG_SYNC="reset";
######################################
# Equals to -1 if the bug is not fixed. I.e.
# innodb_counter_value[MONITOR_OVLD_ROW_LOCK_CURRENT_WAIT].mon_start_value is
# set to 1 during
# "set global innodb_monitor_disable='lock_row_lock_current_waits'" execution,
# and the value is counted as
# (value = 0) - (mon_value_reset = 0) - (mon_start_value = 1) +
# (mon_last_value = 0) = -1. See MONITOR_SET_DIFF() macro in
# srv_mon_process_existing_counter() for details.
#####
SELECT name, count FROM information_schema.innodb_metrics
WHERE name ='lock_row_lock_current_waits';
DROP TABLE `t`;
SET GLOBAL innodb_monitor_disable='lock_row_lock_current_waits';
SET GLOBAL innodb_monitor_reset_all='lock_row_lock_current_waits';
SET GLOBAL innodb_monitor_enable='lock_row_lock_current_waits';
--disable_warnings
SET GLOBAL innodb_monitor_disable=default;
SET GLOBAL innodb_monitor_reset_all=default;
SET GLOBAL innodb_monitor_enable=default;
--enable_warnings
--disconnect prevent_purge
--source include/wait_until_count_sessions.inc

1
storage/innobase/lock/lock0wait.cc
View File

@ -340,6 +340,7 @@ lock_wait_suspend_thread(
thd_wait_begin(trx->mysql_thd, THD_WAIT_TABLE_LOCK);
}
DEBUG_SYNC_C("lock_wait_before_suspend");
os_event_wait(slot->event);
DBUG_EXECUTE_IF("small_sleep_after_lock_wait",
{

2
storage/innobase/srv/srv0mon.cc
View File

@ -145,7 +145,7 @@ static monitor_info_t innodb_counter_info[] =
"Number of row locks currently being waited for"
" (innodb_row_lock_current_waits)",
static_cast<monitor_type_t>(
MONITOR_EXISTING | MONITOR_DEFAULT_ON),
MONITOR_EXISTING | MONITOR_DISPLAY_CURRENT | MONITOR_DEFAULT_ON),
MONITOR_DEFAULT_START, MONITOR_OVLD_ROW_LOCK_CURRENT_WAIT},
{"lock_row_lock_time", "lock",