Commit 7949ffc8 authored by unknown's avatar unknown
Browse files

InnoDB: tolerate system clock glitches a little better 

in the error monitor thread.  (Bug #5898)


innobase/include/sync0arr.h:
  sync_array_print_long_waits(): return error status
innobase/srv/srv0srv.c:
  srv_error_monitor_thread(): Keep track on successive fatal timeouts,
  and crash the server only if the timeouts have been exceeded for
  several times in succession.
innobase/sync/sync0arr.c:
  sync_array_print_long_waits(): return error status
parent 1601646a

innobase/include/sync0arr.h

+3 −1
Original line number Diff line number Diff line
@@ -97,9 +97,11 @@ sync_arr_wake_threads_if_sema_free(void); 
/**************************************************************************

Prints warnings of long semaphore waits to stderr. */



void

ibool

sync_array_print_long_waits(void);

/*=============================*/

			/* out: TRUE if fatal semaphore wait threshold

			was exceeded */

/************************************************************************

Validates the integrity of the wait array. Checks

that the number of reserved cells equals the count variable. */

innobase/srv/srv0srv.c

+16 −4
Original line number Diff line number Diff line
@@ -1754,7 +1754,8 @@ srv_error_monitor_thread( 
			/* in: a dummy parameter required by

			os_thread_create */

{

	ulint	cnt	= 0;

	/* number of successive fatal timeouts observed */

	ulint	fatal_cnt	= 0;



#ifdef UNIV_DEBUG_THREAD_CREATION

	fprintf(stderr, "Error monitor thread starts, id %lu\n",
@@ -1763,8 +1764,6 @@ srv_error_monitor_thread( 
loop:

	srv_error_monitor_active = TRUE;



	cnt++;



	os_thread_sleep(2000000);



	if (difftime(time(NULL), srv_last_monitor_time) > 60) {
@@ -1774,7 +1773,20 @@ srv_error_monitor_thread( 
		srv_refresh_innodb_monitor_stats();

	}



	sync_array_print_long_waits();

	if (sync_array_print_long_waits()) {

		fatal_cnt++;

		if (fatal_cnt > 5) {



			fprintf(stderr,

"InnoDB: Error: semaphore wait has lasted > %lu seconds\n"

"InnoDB: We intentionally crash the server, because it appears to be hung.\n",

				srv_fatal_semaphore_wait_threshold);



			ut_error;

		}

	} else {

		fatal_cnt = 0;

	}



	/* Flush stderr so that a database user gets the output

	to possible MySQL error file */

innobase/sync/sync0arr.c

+7 −8
Original line number Diff line number Diff line
@@ -889,15 +889,18 @@ sync_arr_wake_threads_if_sema_free(void) 
/**************************************************************************

Prints warnings of long semaphore waits to stderr. */



void

ibool

sync_array_print_long_waits(void)

/*=============================*/

			/* out: TRUE if fatal semaphore wait threshold

			was exceeded */

{

        sync_cell_t*   	cell;

        ibool		old_val;

	ibool		noticed = FALSE;

	ulint           i;

	ulint		fatal_timeout = srv_fatal_semaphore_wait_threshold;

	ibool		fatal = FALSE;



        for (i = 0; i < sync_primary_wait_array->n_cells; i++) {
@@ -914,13 +917,7 @@ sync_array_print_long_waits(void) 
                if (cell->wait_object != NULL

		    && difftime(time(NULL), cell->reservation_time)

		    > fatal_timeout) {



			fprintf(stderr,

"InnoDB: Error: semaphore wait has lasted > %lu seconds\n"

"InnoDB: We intentionally crash the server, because it appears to be hung.\n",

				fatal_timeout);



		    	ut_error;

			fatal = TRUE;

                }

       	}
@@ -948,6 +945,8 @@ sync_array_print_long_waits(void) 
		fprintf(stderr,

"InnoDB: ###### Diagnostic info printed to the standard error stream\n");

	}



	return(fatal);

}



/**************************************************************************