ODBC Server Installation and Management Manual

Managing NonStop ODBC Server Resources
HP NonStop ODBC Server Installation and Management Manual—429395-002
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Security Considerations
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Continue, realizing that accounting data will not be recorded for any subsequent
statements.
It is recommended that the database administrator create a tool (such as a system-
stored procedure) either to summarize the data to another history table or to archive it
to a tape. The database administrator should periodically generate the resource
accounting report and run this tool to clean up the ZNUMTRX table to prevent an
overflow situation.
Security Considerations
Resource accounting data is stored in SQL tables, which means that data is easily
accessible. To protect any users from inadvertently updating the data, these tables are
owned by the database administrator and are write/purge protected. Tools or clients
with read access should be able to generate reports by using the data.
The catalog table for storing the resource accounting profile is owned by the database
administrator and write protected so only the database administrator can change these
specifications.
Performance Considerations
There is minimal effect on performance when resource accounting data is being
recorded on a per-session basis. If the data is being recorded on a per-statement
basis, however, it incurs a cost of one extra write for every SQL statement. These
INSERT statements for recording the resource accounting data do not appear in the
ZNUMTRX table.
It is important to note that turning tracing on can trigger many INSERT statements and
could generate a large amount of data written to the resource accounting table.
Error Handling
Resource accounting errors are not critical to the execution of user applications. Such
an error is treated as a warning, and a message is logged to the EMS $0 as part of the
NonStop ODBC Server error messaging scheme.
Limitations
It is important to note that the metrics to be collected can be derived only from data
currently available. Because of limitations in SQL/MP, the following metrics are not
available:
•
Process time of the master executor's child processes, such as individual external
stored procedures and SORTPROGs
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I/O statistics from SORTPROGs
•
Process time and I/O statistics of the catalog manager from execution of a DDL
statement