Checking Query Disk Spill Space Usage

posted Jan 20, 2014, 5:52 PM by Sachchida Ojha   [ updated Jan 20, 2014, 5:53 PM ]
Greenplum Database creates work files on disk if it does not have sufficient memory to execute the query in memory. This information can be used for troubleshooting and tuning queries.

The gp_workfile_* views show information about all the queries that are currently using disk spill space. The information in the views can also be used to specify the values for the Greenplum Database configuration parameters gp_workfile_limit_per_query and gp_workfile_limit_per_segment. Let look into details about these views.

1. gp_workfile_entries
2. gp_workfile_usage_per_query
3. gp_workfile_usage_per_segment

1. gp_workfile_entries
This view contains one row for each operator using disk space for workfiles on a segment at the current time. The view is accessible to all users, however non-superusers only to see information for the databases that they have permission to access.

2. gp_workfile_usage_per_query
This view contains one row for each query using disk space for workfiles on a segment at the current time. The view is accessible to all users, however non-superusers only to see information for the databases that they have permission to access.

3. gp_workfile_usage_per_segment
This view contains one row for each segment. Each row displays the total amount of disk space used for workfiles on the segment at the current time. The view is accessible to all users, however non-superusers only to see information for the databases that they have permission to access

Note: Above views are available from V 4.2.5 and above.
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