| If the system is CPU-bound or disk-bound, or the processing is skewed. |
- Look at physical resource utilization:
Use Teradata Viewpoint. Monitor physical resources to view CPU/disk usage by node. Monitor virtual resources to view CPU/disk usage by vproc.
Look at DBC.ResusageSpma to view CPU, disk, and BYNET usage.
- Look at workload utilization:
Use DBQL to find the user with the skewed processing.
- Look at data distribution:
Use DBC.TableSizeV to identify tables with skewed data distribution.
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| If the processing is skewed, identify the user. |
- Use Teradata Viewpoint.
- Check DBC.SessionInfoV or run Query Session to identify the current user.
- Check DBC.LogOnOffV to view historical users.
- Check DBC.AMPUsage to identify the heavy resource user.
- Check DBC.DiskSpaceV to identify large spool user.
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| If the processing is skewed, get information on the problematic query. |
- To identify the query, ask the user or check query log.
- Run EXPLAIN on the query to determine if a bad join plan exists. Look for unexpected product joins. Verify that large tables are not joined before small tables. Look for estimates that are too high or too low.
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