8.7 Dynamic Runtime Instrumentation Tools Architecture (DRITA)

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8 Performance Analysis and Tuning : 8.7 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 offers this functionality, while consuming minimal system resources.
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.
Advanced Server's postgresql.conf file includes a configuration parameter named timed_statistics that controls the collection of timing data. The valid parameter values are TRUE or FALSE; the default value is FALSE.
This is a dynamic parameter which can be modified in the postgresql.conf file, or while a session is in progress. To enable DRITA, you must either:
Modify the postgresql.conf file, setting the timed_statistics parameter to TRUE.
After modifying the timed_statistics parameter, take a starting snapshot. A snapshot captures the current state of each timer and event counter. The server will compare the starting snapshot to a later snapshot to gauge system performance.
Use the edbsnap() function to take the beginning snapshot:

8 Performance Analysis and Tuning : 8.7 Dynamic Runtime Instrumentation Tools Architecture (DRITA)

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