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debug_sync: Implement NO_CLEAR_EVENT syntax

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When waiting on a signal, NO_CLEAR_EVENT allows one to not clear the
signal, effectively allowing other threads to wait for the same signal.
This commit is contained in:
Vicențiu Ciorbaru 2021-09-29 11:24:05 +03:00
parent 8885225de6
commit cd873c8688
3 changed files with 43 additions and 2 deletions
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16
mysql-test/main/debug_sync.result
View File

@ -299,4 +299,20 @@ disconnect con1;
disconnect con2;
connection default;
DROP TABLE t1;
#
# Test NO_CLEAR_EVENT flag. The signal should still be visible after
# the wait has completed succesfully.
#
SET DEBUG_SYNC= 'now SIGNAL s1';
SHOW VARIABLES LIKE 'DEBUG_SYNC';
Variable_name Value
debug_sync ON - current signals: 's1'
SET DEBUG_SYNC= 'now WAIT_FOR s1 NO_CLEAR_EVENT';
SHOW VARIABLES LIKE 'DEBUG_SYNC';
Variable_name Value
debug_sync ON - current signals: 's1'
SET DEBUG_SYNC= 'now WAIT_FOR s1';
SHOW VARIABLES LIKE 'DEBUG_SYNC';
Variable_name Value
debug_sync ON - current signals: ''
SET DEBUG_SYNC= 'RESET';

11
mysql-test/main/debug_sync.test
View File

@ -428,6 +428,17 @@ disconnect con2;
connection default;
DROP TABLE t1;
--echo #
--echo # Test NO_CLEAR_EVENT flag. The signal should still be visible after
--echo # the wait has completed succesfully.
--echo #
SET DEBUG_SYNC= 'now SIGNAL s1';
SHOW VARIABLES LIKE 'DEBUG_SYNC';
SET DEBUG_SYNC= 'now WAIT_FOR s1 NO_CLEAR_EVENT';
SHOW VARIABLES LIKE 'DEBUG_SYNC';
SET DEBUG_SYNC= 'now WAIT_FOR s1';
SHOW VARIABLES LIKE 'DEBUG_SYNC';
#
# Cleanup after test case.
# Otherwise signal would contain 'flushed' here,

18
sql/debug_sync.cc
View File

@ -48,6 +48,8 @@ struct st_debug_sync_action
String wait_for; /* signal to wait for */
String sync_point; /* sync point name */
bool need_sort; /* if new action, array needs sort */
bool clear_event; /* do not clear signal when waited
for if false. */
};
/* Debug sync control. Referenced by THD. */
@ -1253,6 +1255,7 @@ static bool debug_sync_eval_action(THD *thd, char *action_str, char *action_end)
/* Set default for EXECUTE and TIMEOUT options. */
action->execute= 1;
action->timeout= opt_debug_sync_timeout;
action->clear_event= true;
/* Get next token. If none follows, set action. */
if (!(ptr= debug_sync_token(&token, &token_length, ptr, action_end)))
@ -1303,6 +1306,15 @@ static bool debug_sync_eval_action(THD *thd, char *action_str, char *action_end)
goto set_action;
}
/*
Try NO_CLEAR_EVENT.
*/
if (!my_strcasecmp(system_charset_info, token, "NO_CLEAR_EVENT")) {
action->clear_event= false;
/* Get next token. If none follows, set action. */
if (!(ptr = debug_sync_token(&token, &token_length, ptr, action_end))) goto set_action;
}
/*
Try HIT_LIMIT.
*/
@ -1591,8 +1603,10 @@ static void debug_sync_execute(THD *thd, st_debug_sync_action *action)
}
error= 0;
}
// TODO conditional on clear-event
debug_sync_global.clear_signal(action->wait_for);
if (action->clear_event)
debug_sync_global.clear_signal(action->wait_for);
DBUG_EXECUTE("debug_sync_exec",
if (thd->killed)
DBUG_PRINT("debug_sync_exec",