The Admin> Settings view enables Command Center administrators to configure settings for Command Center features.
Query Monitor Guest Access Settings
Turn on Allow guests to view Query Monitor to allow users access to the Query Monitor without logging in. When enabled, the Allow guests to view Query Monitor feature allows anyone with access to the Greenplum Command Center web server to click View Query Monitor on the Command Center sign-in screen and see the Query Monitor page without logging in. These anonymous users cannot cancel queries and cannot access any other Command Center features.
When this feature is off, the View Query Monitor link does not appear on the sign-in screen and anonymous users cannot see the Query Monitor page.
Command Center users with Admin permission can toggle the feature on an off with a mouse click. Users with Operator or Operator Basic permission see a message reporting if the feature is on or off.
History Settings
Turn on Enable GPCC history data collection to save query history, host metrics, and disk usage metrics to tables in the gpperfmon database gpmetrics schema. This option defaults to on for a VMware Greenplum 6 installation, but the VMware Greenplum metrics collector extension is inactive until Command Center is started.
Enter a number of seconds to set the minimum runtime for a query to be saved in history. The default is to save all queries. Set this threshold to prevent Command Center from filling history with trivial queries.
When you enable GPCC history data collection:
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Command Center saves query and metrics history in the gpmetrics schema tables in the gpperfmon database. Only queries that execute for at least the number of seconds you specify are saved. Query plan node history is only saved for queries that run for at least 10 seconds, or the number of seconds you specify, if greater than 10.
See gpmetrics Schema Reference for information about the gpmetrics history tables.
Configure Retention Period For History Data
When History data collection is enabled, you may specify how long Command Center stores historical usage data in the gpcc_*_history tables. The default is to keep the data forever.
Using the History Data Retention Period dropdown menu, you may choose to have Command Center keep the data for 3 months, 6 months, 12 months, 24 months, or forever. In addition, for values other than Forever, you may configure the time of day at which Command Center purges the data, in the History Data Purge Time dropdown menu.
Once you have selected values in each of these two dropdown menus, click Save to save your selection.
Performance Settings
Configure Performance Settings to tune the the Command Center backend’s overall resource consumption. You may tune a number of settings:
Sampling Interval
Specifies, in seconds, how often Command Center agents sample queries. The default is 5. Increase this value if the agent is consuming too many resources.
You may also change this value by setting the sampling_interval parameter in the gpmetrics configuration file (gpcc.conf).
Number of Sampling Threads
Limits the number of threads the Command Center agent uses in a one-time sampling.
NOTEYou should only adjust this value when Command Center agents are experiencing severe performance issues on segment hosts.
Set the value based on the number of the running Postgres progresses on the segment hosts. If the value is too small, the collected metrics will be inaccurate. If the value is too large, Command Center may interfere with the performance of the segments. By default, there is no limit.
You may also change this value by setting the sampling_threads parameter in the gpmetrics configuration file (gpcc.conf).
Table Statistics Check Interval
Specifies, in minutes, how often Command Center refreshes the statistics in the Table Browser. The default is 5, which is also the minimum accepted value. If the value you set is not divisible by 60 it will be rounded to the nearest minute.
Increase this value if the table statistics checking causes performance issues.
New tables and changed values such as the file size and the last access time may not be seen until the number of seconds specified in the configuration parameter stats_check_interval have elapsed.
You may also change this value by setting the stats_check_interval parameter in the gpmetrics configuration file (gpcc.conf). To disable table statistics collection, set this stats_check_interval to -1.
NOTEIn the configuration file, the value unit is seconds.
Table Size Check
When enabled, Command Center calculates table sizes when checking table statistics information. Disable it to save computing resources.
You may also change this value by setting the disable_size_check parameter in the gpmetrics configuration file (gpcc.conf).
You may update table sizes by running the gpcc-util table-scan command.
Agent Memory Limit
Limits the percentage of virtual memory that an agent process uses. When this limit is reached, Command Center terminates the agent to release the memory and then restarts the agent after approximately 15 seconds.
You may also change this value by setting the agent_virt_mem_percent parameter in the gpmetrics configuration file (gpcc.conf).
NOTEThis does not affect the agent on the coordinator host. If the agent on the coordinator host consumes too much memory, you must restart it manually to release the memory, by running the
gpcc startcommand.
Visual Plan Collection
Use this setting to enable and disable the displaying of the visual query plan tree. When you enable this setting, Command Center prompts you to reload the database by clicking a button.
Setting the server configuration parameter gpcc.enable_send_instrument enables this setting.
Keep this setting disabled to realize better performance when workloads are mainly engaged in transactional processing (OLTP).
