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Teradata RDBMS Database Administration - NCR

NCR Teradata RDBMS Database Administration - NCR , 2004. - 616 p.
Download (direct link): teradatadatabaseadmin2004.pdf
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In the application phase, the system completes data transfer to the AMP from the client, and the AMPs process the various insert, update, and delete operations on the designated rows in the specified table. The system performs work mainly during the Teradata SQL session and also charges the work to the AMPs. Although AMPs or PEs are accumulating data in the Teradata SQL session, you may not notice the accumulation of data for a few sampling periods, depending on the size of the MultiLoad job or the sampling rate.

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Appendix B: Import/Export Utilities

Monitoring a FastLoad or MultiLoad Job

MultiLoad Phases Start of MultiLoad Phase 1 Teradata SQL Session n MLOAD Sessions
Acquisition Phase MultiLoad Acquisition Phase The system performs a small amount of work. AMPState or PEState looks IDLE most of the time and does not show resource usage. System charges work to AMPs. In Teradata Manager, AMPState or PEState is non-idle most of time; AMPCPU and AMPIO show resource usage.
Application Phase MultiLoad Application Phase System charges work to AMPs. In Teradata Manager, AMPState or PEState is non-idle most of time; AMPCPU or PECPU and AMPIO show resource usage.

Data Transfer Phase

Work is performed in two different partitions during the data transfer phase of a FastLoad or MultiLoad job:

Partition Description
Teradata SQL The system logs on one session under this partition. This session: Parses FastLoad/MultiLoad commands Performs security checking Controls the process of executing the FastLoad/MultiLoad job During the data transfer phase, the session processes CHECKPOINT commands that verify that previously transmitted data has been written to disk on the Teradata RDBMS. Note that for the Teradata SQL session, even though the client (or host) does not have an outstanding request, AMPs show usage of Central Processing Unit (CPU) and I/O resources.
FASTLOAD or MLOAD Under this partition, the system logs on n sessions under this partition, where n is greater than zero and less than or equal to the number of AMPs. These sessions each have a RunProcId corresponding to an AMP, and perform the initial data loading process. Once the system transfers all data to the AMPs, these sessions become idle. Note that when the data transfer phase complete, the AMPCPUSec and AMPIO values remain constant at the last value reported before data transfer completes on the FASTLOAD or MLOAD sessions. Your FastLoad or MultiLoad job is not hung because no increment in values has occurred.

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Teradata RDBMS Database Administration Appendix B: Import/Export Utilities

Monitoring a FastLoad or MultiLoad Job

Work is charged to different sessions during the data transfer phase. The following types of work are performed:

On AMPs that initially receive blocks of data transferred from the host (or client):

- Translate the data into internal Teradata RDBMS format.

- Perform some legality checking.

- Transmit the data to the AMP where it will be permanently stored. The system charges resources to the individual FASTLOAD/ MLOAD partition sessions.

On the AMPs where the data will be stored, that is, the AMPs which own the rows based on the Hash of the PI fields of the table:

- Collect the data rows into a buffer.

- Write the data to disk when the buffer is full.

- Process the CHECKPOINT operations periodically generated by the FastLoad/MultiLoad application. The system charges resources to the Teradata SQL partition session.

As far as the host (or client) is concerned, during the time data is transferred to the Teradata RDBMS, the Teradata SQL session does not have any outstanding requests. Thus, for the Teradata SQL session, the PEState is IDLE and the AMPState is ACTIVE, showing the consumption of large amounts of CPU and I/O resources. The only time a request is outstanding on this session is during the brief periods when the system is running a CHECKPOINT operation.

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Appendix B: Import/Export Utilities

Monitoring an ARC Job

Monitoring an ARC Job

This section describes how the nature of work done during the data loading phase and the table processing phase of an ARC job determines where and when the work is charged to the different sessions.

Consequently, the pattern of work charged to different sessions causes Teradata Manager to display resource usage of data in a particular way.

LSN

Like FastLoad and MultiLoad, the system logs on all sessions associated with the same ARC job as the same user name and with the same LSN.

LSN is associated with a session when the system logs on, and identifies a collection of sessions performing the same job.

To determine the total impact of an ARC job, calculate the total impact of all sessions reported with the same LSN.

I Resource Usage Charges

The system charges work or the part of the job done in a session partition to that partition. For those sessions in which work is charged to AMPs, the following resource usage is displayed in Teradata Manager:
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