SET_DATA_COLLECTOR_POLICY

Updates selected retention policy properties for a specified component. SET_DATA_COLLECTOR_POLICY (using parameters) is another version of this function that uses named parameters instead of positional arguments.

Before you change a retention policy, you can view its current settings by querying the DATA_COLLECTOR table or by calling the GET_DATA_COLLECTOR_POLICY function.

This is a meta-function. You must call meta-functions in a top-level SELECT statement.

Behavior type

Syntax

SET_DATA_COLLECTOR_POLICY('component', 'memory-buffer-size', 'disk-size' [,'interval-time']  )

Arguments

component

The retention policy to update.

Query DATA_COLLECTOR to get a list of components:

=> SELECT DISTINCT component, description FROM DATA_COLLECTOR 
   WHERE component ILIKE '%Depot%' ORDER BY component;
   component    |          description
----------------+-------------------------------
 DepotEvictions | Files evicted from the Depot
 DepotFetches   | Files fetched to the Depot
 DepotUploads   | Files Uploaded from the Depot
(3 rows)

memory-buffer-size

Maximum amount of data, in kilobytes, that is buffered in memory before moving it to disk. The retention policy property MEMORY_BUFFER_SIZE_KB is set from this value. This value must be positive and greater than 0.

Consider setting this parameter to a high value in the following cases:

• Unusually high levels of data collection. If the value is too low, the Data Collector might be unable to flush buffered data to disk quickly enough to keep up with the activity level, which can lead to loss of in-memory data.

• Very large data collector records—for example, records with very long query strings. The Data Collector uses double-buffering, so it cannot retain in-memory records that are more than half the size of the memory buffer.

disk-size

Maximum disk space, in kilobytes, allocated for this component's Data Collector table. The retention policy property DISK_SIZE_KB is set from this value. If set to 0, the Data Collector retains only as much component data as it can buffer in memory, as specified by memory-buffer-size.

interval-time

How long to retain data in the component's Data Collector table, an INTERVAL. The INTERVAL_TIME retention policy property is set from this value. If the value is positive, it also sets the INTERVAL_SET policy property to true.

For example, if you specify the TupleMoverEvents component and set this value to two days ('2 days'::interval), the DC_TUPLE_MOVER_EVENTS Data Collector table retains records over the last 48 hours. Older Tuple Mover data is automatically dropped from this table.

Setting a component's policy's INTERVAL_TIME property has no effect on how much data storage the Data Collector retains on disk for that component. Maximum disk storage capacity is determined by the DISK_SIZE_KB property. Setting the INTERVAL_TIME property only affects how long data is retained by the component's Data Collector table. For details, see Configuring data retention policies.

To disable the INTERVAL_TIME policy property, set this value to a negative integer. Doing so reverts two retention policy properties to their default settings:

• INTERVAL_SET: false

• INTERVAL_TIME: 0

With these two properties thus set, the component's Data Collector table retains data on all component events until it reaches its maximum limit, as set by the DISK_SIZE_KB retention policy property.

Privileges

Superuser

Examples

=> SELECT SET_DATA_COLLECTOR_POLICY('ResourceAcquisitions', '1500', '25000');
 SET_DATA_COLLECTOR_POLICY
---------------------------
 SET
(1 row)

See also

• SET_DATA_COLLECTOR_POLICY (using parameters)
• Configuring data retention policies