System limit alerts

Some system limits are instrumented by the IBM® i operating system to send messages to the QSYSOPR message queue when a threshold value has been reached.

Once each day, the IBM i will look for any limits that have surpassed their alerting level. This happens when Collection Services is recycled, typically just past midnight. At this time, a call is made to the QSYS2.PROCESS_SYSTEM_LIMITS_ALERTS procedure to identify and signal any alerts for the day.

The following limits are checked against their alerting level as part of this daily processing. If the level is exceeded, Start of change a severity 80 informational message SQL7062 End of change is sent to the QSYSOPR message queue. Since these limits will prevent database or other system activity from continuing if they are reached, you should take action to get the object's percent used for the limit below the alerting level. Reducing data by archiving it is one example of an action that could be taken.

Table 1. System limits that send alerting messages
Limit ID	Limit description	Maximum	Default Alerting Level	Alerting Cadence
15000	Maximum number of all rows in a partition	4,294,967,288	Greater than 90%	Once per day
15003	Maximum size of a table	1,869,169,767,219	Greater than 90%	Once per day
15104	Maximum number of variable-length segments	65,533	Greater than 90%	Once per day
15400	Maximum *MAX4GB Index Size	4,294,967,296	Greater than 90%	Once per day
15401	Maximum *MAX1TB Index Size	1,869,166,411,776	Greater than 90%	Once per day
15403	Maximum Encoded Vector Index Size	2,199,023,255,552	Greater than 90%	Once per day
19002	Maximum number of spooled files	2,610,000	Greater than 90%	Once per day

The SQL7062 QSYSOPR message is formatted like this:

MYLIB/MYTABLE *FILE HAS CONSUMED MORE THAN 90% OF THE LIMIT: 
15000-MAXIMUM NUMBER OF ALL ROWS (4008420999 OF 4294967288=93.33%). 
REFER TO ibm.biz/DB2foriAlerts FOR MORE DETAIL.

System limit alerts global variables

For each limit that is instrumented to send a system limit alert, a corresponding global variable is defined that can be used to modify the consumption level that causes the alert to be issued.

The following are the names of the global variables. The schema is SYSIBMADM.

Limit ID	Global variable	Shipped limit
15000	QIBM_SYSTEM_LIMITS_ALERT_15000_PERCENTAGE	90
15003	QIBM_SYSTEM_LIMITS_ALERT_15003_PERCENTAGE	90
15104	QIBM_SYSTEM_LIMITS_ALERT_15104_PERCENTAGE	90
15400	QIBM_SYSTEM_LIMITS_ALERT_15400_PERCENTAGE	90
15401	QIBM_SYSTEM_LIMITS_ALERT_15401_PERCENTAGE	90
15403	QIBM_SYSTEM_LIMITS_ALERT_15403_PERCENTAGE	90
19002	QIBM_SYSTEM_LIMITS_ALERT_19002_PERCENTAGE	90

You can redefine any of the global variable values to change the alerting percent on your system. The change will take effect the next time the altering levels are checked.

Use IBM i Access Client Solutions (ACS) to generate SQL for the global variable and use the OR REPLACE option to recreate it with a different default. For example, to send an alert when a file reaches 70% of its maximum size, use the following SQL statement:

CREATE OR REPLACE VARIABLE SYSIBMADM.QIBM_SYSTEM_LIMITS_ALERT_15000_PERCENTAGE 
	INTEGER   
	DEFAULT 70