Built-in tasks and sensors
The Scheduler contains built-in tasks and sensors that run automatically.
The following table shows the built-in Scheduler tasks
and sensors. Sensors have results tables to store the information
they collect, and retention periods to determine how long that information
is stored. You can change task and sensor properties, for example,
the frequency, by updating the ph_task table. Some tasks are
triggered by thresholds. You can change thresholds by updating the ph_threshold table.
You can disable a task or sensor by changing the value of the tk_enable column
in the ph_task table to f.
You can determine how long tasks take by querying the run_duration column in the ph_task table.
| Task or sensor | Description | Results table | Frequency | Retention |
|---|---|---|---|---|
| add_storage | This task add more storage space automatically when automatic space management is configured. | As needed | ||
| Alert Cleanup | This task removes all alert entries from the ph_alert table that are older than the threshold of 15 days. The threshold is named ALERT HISTORY RETENTION in the ph_threshold table. | Once a day | ||
| auto_compress | This task compresses tables that are configured for automatic compression. | |||
| auto_crsd | This task compresses, shrinks, repacks, and
defragments tables and fragments. By default, this task is disabled. You must enable it by updating the ph_task table. Each of the operations has 2 rows in the ph_threshold table: one to control whether it is enabled and one to control its threshold. For more information, see Scheduling data optimization. |
Once a week | ||
| autoreg exe | This task registers database extensions when they are first used. | As necessary | ||
| autoreg migrate-console | Internal. This task checks every database with a logging option of log or buffered log, and, if necessary, migrates all built-in database extensions to the correct version for the database server. This task creates sub-tasks for individual databases, as necessary. | At server startup | ||
| autoreg vp | This task creates a specialized virtual processor for a database extension as necessary. | As necessary | ||
| auto_tune_cpu_vps | This task automatically adds CPU virtual processors
if the number of allocated VPs is less than half the number of CPU
processors on the computer. For more information, see Automatic addition of CPU virtual processors. |
At server startup | ||
| Auto Update Statistics Evaluation | This task analyzes all the tables in all logged
databases, identifies the tables whose distributions must be updated,
and generates UPDATE STATISTICS statements for those tables, based
on the current automatic update statistics (AUS) policies. The AUS
policies are set by thresholds in the ph_threshold table:
For more information, see Automatic statistics updating. |
Once a day | ||
| Auto Update Statistics Refresh | This task runs the UPDATE STATISTICS statements generated by the Auto Update Statistics Evaluation task. The PDQ priority for updating statistics is set to 10 by the threshold named AUS_PDQ in the ph_threshold table. | Saturday and Sunday between 1:00 AM and 5:00 AM | ||
| bad_index_alert | This task checks for corrupted indexes. If any
corrupted indexes are found, a warning alert is added to the ph_alert table. For more information, see Validate indexes. |
Once a day | ||
| bar_act_log_rotate | This task rotates the ON-Bar activity log file
that is specified in the BAR_ACT_LOG configuration parameter. When the ON-Bar activity log rotates, the server switches to a new online message log file and increments the ID numbers for the previous log files by one. When the maximum number of log files is reached, the log file with the highest ID is deleted. The threshold for the maximum logs to rotate is specified in the ph_threshold table. |
3 A.M. every 30 days (with a maximum of 12 log files) | ||
| bar_debug_log_rotate | This task rotates the ON-Bar debug log file
that is specified in the BAR_DEBUG_LOG configuration parameter. When the ON-Bar debug log rotates, the server switches to a new online message log file and increments the ID numbers for the previous log files by one. When the maximum number of log files is reached, the log file with the highest ID is deleted. The threshold for the maximum logs to rotate is specified in the ph_threshold table. |
3 A.M. every 30 days (with a maximum of 12 log files) | ||
| check_backup | This task checks to ensure that backups have
run since the time specified by thresholds in the ph_threshold table:
If a backup has not occurred, a warning alert is added to the ph_alert table. |
Once a day | ||
| check_for_ipa | This task adds an entry in the ph_alert table for each table that has one or more outstanding in-place alter operations. | Once a week | ||
| idle_user_timeout | This task terminates user sessions that have
been idle for longer than 60 minutes. By default, this task is disabled. You must enable it by updating the ph_task table. For more information, see Automatically terminating idle connections. |
Every 2 hours | ||
| ifx_ha_monitor_log_replay_task | This task monitors the high-availability cluster replay position. | Not set | ||
| mon_checkpoint | This sensor saves information about checkpoints. | mon_checkpoint | Every hour | 7 days |
| mon_chunk | This sensor saves general information about chunk usage and I/O chunk performance. | mon_chunk | Every hour | 30 days |
| mon_command_history | This task deletes rows from the command_history table that are older than the threshold of 30 days. The threshold is named COMMAND HISTORY RETENTION in the ph_threshold table. | Once a day | ||
| mon_compression_estimates | This sensor saves information about how much space might be saved if the data is compressed. | mon_compression_ estimates | Once a week | 30 days |
| mon_config | This sensor saves the most recent value for each configuration parameter in the onconfig file. | mon_config | Once a day | |
| mon_config_startup | This sensor saves the value for each configuration parameter in the onconfig file when the server starts. | mon_config | At server startup | 99 days |
| mon_iohistory | This sensor saves performance information about chunk I/O. You can change the IO_SAMPLES_PER_HOUR parameter in the ph_threshold table to collect information more frequently. | Every hour | 30 days | |
| mon_low_storage | This
task scans the list of dbspaces to find spaces that fall below the
threshold specified by the SP_THRESHOLD configuration parameter. Then,
the task expands the spaces by extending chunks or adding chunks using
entries in the storage pool. For more information, see Automatic space management. |
mon_low_storage | Every hour | 7 days |
| mon_memory_system | This sensor collects information about the amount of memory the server uses. | mon_memory_system | Every hour | 7 days |
| mon_page_usage | This sensor saves information about the pages that are used and free in storage spaces. | mon_page_usage | Once a day | 7 days |
| mon_profile | This sensor saves server profile information. | mon_prof | Every 4 hours | 30 days |
| mon_sysenv | This startup sensor saves information about the environment when the database server starts. | mon_sysenv | At server startup | 60 days |
| mon_table_names | This sensor saves table names along with their creation time. | mon_table_names | Once a day | 30 days |
| mon_table_profile | This sensor saves table profile information, including the total number of update, insert, and delete operations that occurred on this table. | mon_table_profile | Once a day | 7 days |
| mon_users | This sensor saves profile information about each user. | mon_users | Every 4 hours | 7 days |
| mon_vps | This sensor collects virtual processor information. | mon_vps | Every 4 hours | 15 days |
| online_log_rotate | This task rotates the online message log file
that is specified in the MSGPATH configuration parameter. When the online message log rotates, the server switches to a new online message log file and increments the ID numbers for the previous log files by one. When the maximum number of log files is reached, the log file with the highest ID is deleted. The threshold for the maximum logs to rotate is specified in the ph_threshold table. |
3 A.M. every 30 days (with a maximum of 12 log files) | ||
| post_alarm_message | This task posts alerts. | Every hour | ||
| purge_tables | This task identifies rolling window tables whose purge policies have been exceeded. It discards or detaches qualifying fragments, according to each purge policy, until that policy is satisfied, or until no more fragments can be removed. | Daily at 00:45 | ||
| SET tk_enable | This task enables the tasks that rotate message log files. | 3 A.M. every 30 days | ||
| sync_registry | This task automatically converts the connection information between the sqlhosts file format and the Windows™ registry format. | Every 15 minutes |