Postgres Plus Advanced Server Oracle Compatibility Developer's Guide : 11.4 Dynamic Runtime Instrumentation Tools Architecture (DRITA)

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Postgres Plus Advanced Server Oracle Compatibility Developer's Guide

 

11.4 Dynamic Runtime Instrumentation Tools Architecture (DRITA)

The Dynamic Runtime Instrumentation Tools Architecture (DRITA) allows a DBA to query catalog views to determine the wait events that affect the performance of individual sessions or the system as a whole. DRITA records the number of times each event occurs as well as the time spent waiting; you can use this information to diagnose performance problems.

DRITA compares snapshots to evaluate the performance of a system. A snapshot is a saved set of system performance data at a given point in time. Each snapshot is identified by a unique ID number; you can use snapshot ID numbers with DRITA reporting functions to return system performance statistics.

DRITA consumes minimal system resources.

11.4.1 Initialization Parameters

DRITA includes a configuration parameter, timed_statistics, to control the collection of timing data. This is a dynamic parameter that can be set in the postgresql.conf file or while a session is in progress. The valid values are TRUE or FALSE; the default value is FALSE.

11.4.2 Setting up and Using DRITA

To use DRITA, you must first create a small set of tables and functions. To create the tables and functions that store and report information, run the following scripts:

snap_tables.sql 
snap_functions.sql 

After creating the required tables and functions, take a beginning snapshot. The beginning snapshot will be compared to a later snapshot to gauge system performance. To take a beginning snapshot:

SELECT * from edbsnap()

Then, run the workload that you would like to evaluate; when the workload has completed (or at a strategic point during the workload), take an ending snapshot:

SELECT * from edbsnap()

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