What is AWR analysis?

An AWR report has data on database activity between two points in time – two snapshots. It has many different sections with a large amount of database performance data. You can use this information to compare statistics captured during a period of bad performance to a baseline, and diagnose performance issues.

How do I get an AWR report?

To generate an AWR Compare Periods report on the local database instance using the command-line interface:

1. At the SQL prompt, enter: @$ORACLE_HOME/rdbms/admin/awrddrpt.sql.
2. Specify whether you want an HTML or a text report: Enter value for report_type: html.

Which two things should a DBA look for in AWR report?

Look at the Host CPU and Instance CPU sections. The key things to look for are the values “%Idle” in the “Host CPU” section and “%Total CPU” in the “Instance CPU” section. execution plans, especially if accompanied with high (buffer) gets.

How do you find long running queries in AWR?

Answer: You can query the v$session_longops view to find long-running queries and you can query the AWR to find historical queries (if you have purchased the AWR packs).. The Oracle data dictionary contains a little-known view called the v$session_longops.

How can I increase my AWR retention period?

Steps to Modify AWR Snapshot Interval

1. STEP 1: Check the Database name and DBID.
2. STEP 2: Check the existing snapshot_interval time.
3. STEP 3: Modify the existing snapshot interval.
4. STEP 4: Check the modified snapshot interval.

What is the default time interval for AWR snapshot?

Description: AWR snapshot default interval is 60 minutes and its retention are 8 days. In order to investigate detailed database performance related problems, it is recommended to use an interval of 15 minutes and retention of 31 days.

What is db time in AWR?

The DB Time is a time model statistic that is the sum of all Oracle process’ CPU consumption plus the sum of non-idle wait time. When optimizing Oracle databases, we focus on reducing the processing “time”, usually by tuning SQL statements.

What is consistent gets in Oracle?

A ‘consistent get’ is when Oracle gets the data in a block which is consistent. with a given point in time, or SCN. The consistent get is at the heart of. Oracle’s read consistency mechanism.

What is version count in AWR report?

As the AWR report starts reporting on any Version Count > 20; it is a good indicator of a potential performance issue. Version counts in to the hundreds and thousands can be catastrophic and these cases need to be examined and the numers reduced.

How would you troubleshoot a slow running query in Oracle?

Always use EXPLAIN PLAN to troubleshoot a slow running query in Oracle….

1. Find the SQL_ID of the slow running query.
2. Step 2 – Run the SQL Tuning advisor for that SQL_ID.
3. Step 3 – Check the sql plan hash value and pin the good plan:

Why does Oracle query take so long to execute?

On a large table this could take a long time either way, maybe even longer than the 4 or 5 minutes you’re seeing. Once the data is retrieved, the temporary index would be dropped in the background. When you do another query, Oracle needs to build a new temporary index, which is why it takes that long for every query.

Where is the AWR snapshot interval?

You can list AWR Snapshots by executing following command to see Snapshots and their Intervals. SQL> select snap_id, begin_interval_time,end_interval_time from dba_hist_snapshot; Execute following script to find out Snapshot interval Time and Retention Day.

How to choose the right AWR report?

If you want to decide right decision, you need to analyze in detail and compare AWR report with minimum two or three AWR report. These AWR reports should be last day’s and last week’s or month’s, namely they should be same load or similar load. To find out whether Load profile’s value is high or not, compare these values with older AWR reports.

What is the difference between dump report and AWR report?

The difference between the dump (heap or thread) and Automatic Workload Repository report is that dump reports are the actual snapshots taken at a particular time whereas AWR report is a comparison report of two snapshots taken at the different timestamps.

What is AWR report in DBMS?

AWR Report In the heap dump and thread dump analyse topics, we have seen that how the snapshot of memory and thread at a particular time describes the whole picture and helps to determine the performance bottleneck. In a similar fashion, the Automatic Workload Repository (also caller AWR) report provides information about the database bottleneck.

How to identify unselective indexes in AWR report?

You need to see then the “File IO Stats” section in the AWR report. The event indicates that index scan is happening while reading data from table. High no. of such event may be a cause of unselective indexes i.e. oracle optimizer is not selecting proper indexes from set of available indexes.