Wednesday, April 28, 2010

STATSPACK and AWR Statistics Comparison(**An Important interview question**)

STATSPACK and AWR Statistics Comparison

The AWR repository holds all of the statistics available in STATSPACK as well as some additional statistics which are not. The following information on statistics is specific to those stored in the AWR that are not part of the STATSPACK:

1)STATSPACK does not store the Active Session History (ASH) statistics available in the AWR dba_hist_active_sess_history view. The ASH allows DBAs to perform time-series analyses of wait events for a particular session history.

2)An important difference between STATSPACK and the AWR is that STATSPACK does not store history for new metric statistics introduced in Oracle10g. The key AWR views, dba_hist_sysmetric_history and dba_hist_sysmetric_summary , help the DBA build time-series reports for important database performance metrics such as Total Time Waited or Response Time Per Txn.

The AWR also contains views such as dba_hist_service_stat , dba_hist_service_wait_class and dba_hist_service_name , which store history for performance cumulative statistics tracked for specific services.

3)The latest version of STATSPACK included with Oracle10g contains a set of specific tables, which track history of statistics that reflect the performance of the Oracle Streams feature. These tables are stats$streams_capture , stats$streams_apply_sum , stats$buffered_subscribers , stats$rule_set , stats$propagation_sender , stats$propagation_receiver and stats$buffered_queues . The AWR does not contain the specific tables that reflect Oracle Streams activity; therefore, if a DBA relies heavily on the Oracle Streams feature, it would be useful to monitor its performance using STATSPACK utility.

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2 comments:

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  2. Hi Ashok...

    Thanks for the suggestion.


    Best regards,

    Rafi.

    ReplyDelete