AWR report Oracle 12C | Oracle Community


awr report

An AWR report shows data captured between two snapshots (or two points in time). The AWR reports are divided into multiple sections. The HTML report includes links that can be used to navigate quickly between sections. The content of the report contains the workload profile of the system for the selected range of ahjanss.gas: 5. Dec 14,  · I have been looking out for help to understand AWR. i did find some resources but many were vague or incomplete or had issue of some sort. Can someone, please point to a resource where i can read and understand AWR on Oracle 12C database. The procedure of report generation in Oracle10g is quite different with AWR. The final AWR report can be built by using the PL/SQL API provided in the dbms_workload_repository package. Two procedures that generate AWR reports from are awr_report_text and awr_report_html. These procedures generate the AWR report for the specified.

Performance Tuning Basics 15 : AWR Report Analysis – Expert Oracle

The report generated by AWR is a big report and it can take years of awr report to actually awr report all aspects of this report. In this post we will try to explain some important sections of AWR, significance of those sections and also some important tips. Please note that explaining all sections of AWR will not be possible so we will stick to some of the most frequently used sections.

Note that this is not comprehensive information and goal is to help in giving an overview of few key sections to Junior DBAs as a primer and to encourage them to build further the knowledge in related fields. Stick to Particular Time: Awr report must have a specific time when Database was slow so that you can choose a shorter timeframe to get a more precise report.

This will help to isolate the problem. This contains information about the Database and environment. Along with the snapshot Ids and times. Important thing to notice is that the configuration like CPU and Memory has not changed when the performance is degraded, awr report. This means that for every minute of Elapsed time there is 2.

Elapsed time should contain the issue duration. Load Profile. Here in load profile average active sessions, DB CPU, awr report, logical and physical reads, awr report, user calls, executions, parses, hard parses, logons, rollbacks, transactions —.

High redo figures mean that either lots of new data is being saved into the database, awr report, or existing data is undergoing lots of changes, awr report. What do you do if you find that redo generation is too high and there is no business reason for that? Just keep an eye open for any suspicious DML activity. Any unusual statements? Or usual statements processed more usual than often? Or produce more rows per execution than usual? Also, be sure awr report take a good look in the segments statistics section segments by physical writes, segments by DB block changes etc.

Same as DB time it does not include background process. That may help in pointing which SQL awr report having more logical reads. These consume both latches and shared pool area. How much hard parsing is acceptable? It depends on too many things, like number of CPUs, awr report, number of executions, how sensitive are plans to SQL parameters etc.

But as a rule of a thumb, awr report, anything below 1 hard parse per second is probably okay, and everything above per second suggests a problem if the database has a large number of CPUs, say, abovethose numbers should be scaled up accordingly. Soft Parses: Soft parses are not listed but derived by subtracting the hard parses from parses, awr report. Clearly, awr report get is less expensive than physical read because database has to work harder and more to get the data, awr report.

In particular, when the database is executing many times per a user call, awr report, this could be an indication awr report excessive context switching e, awr report.

Number of logons Establishing a new database connection is also expensive and even more expensive in case of audit or triggers. Instance Efficiency Percentage. Re parsing is high on CPU and should be avoided. The way this ratio is computed, it will be a number near percent when the application executes a given SQL statement many times over but has parsed it only once.

If the number of parse calls is near the number of execute calls, this ratio trends towards zero. When this number is low, parsing is consuming CPU and shared awr report latching. If the value awr report low then it means that there could be a parsing problem. You may need to look at bind variable issues or shared pool sizing issue.

We awr report start by reviewing library cache contention and contention in shared pool latches. You may need to increase the shared pool. Awr report ratio relates to requests that a server process makes for a specific buffer. This is the percentage of those requests in which the requested buffer is immediately available, awr report.

All buffer types are included in this statistic. If the ratio is low, check the Buffer Wait Statistics section of the report for more detail on which type of block is being contended, awr report.

Most likely, awr report, additional RAM will be required. Note awr report there could be significant waits that are not listed here, so check the Foreground Wait Events Wait Event Statistics section for any other time consuming wait events. Sequential read is an index read followed by table read because it is doing index lookups which tells exactly which block to go to. If you have say very high wait average example ms or ms, it means that your disks are slow.

The event indicates that index scan is happening while reading data from table. High no. Generally high no. In this case, re-building the index will compact its contents into fewer blocks. By rebuilding the table with its rows sorted by the particular index columns we can reduce the Clustering Factor and hence the number of table data blocks that we have to visit for each index block.

The index scan will help in reducing no. This section lists down both Tables and Indexes on which Physical Reads are happening. When first process is reading the block the other processes goes in a wait as the block is in unshared more. Typical scenario for this event to occur is, when we have batch process which is continuously polling database by executing particular SQL repeatedly and there are more than one parallel instances running for the process.

All the instances of the awr report will try to access same memory blocks as the SQL they are executing is the same. This is one of the situation in which we experience this event. Only when the process has acquired lock the process can modify the row otherwise the process waits for the lock. This wait situation triggers this event, awr report. Once the lock is released, processes waiting on this event can acquire lock on the row and perform DML operation.

Host CPU. In either case CPU is a bottleneck or not there could be individual expensive SQLs with high CPU time, which could indicate suboptimal execution plans, especially if accompanied with high buffer gets. Based on load, database server keeps on allocating or deallocating memory assigned to different components of SGA and PGA.

Shared Pool Statistics. Time Model Statistics. Of course, if there are other major CPU users in awr report system, the formula must be adjusted accordingly. Even if it looks like it is big enough, if you aregetting multiple small sorts to disk it could mean your user load is awr report it.

Wait Event Histogram. It means that our disks are working good. Wait is low for most of the sessions going to database, awr report. SQL ordered by Elapsed Time. In this report, look for query has low executions and high Elapsed time awr report Exec s and this query could be a candidate for troubleshooting or optimizations. In above report, you can see first query has maximum Elapsed time but only 2 execution. So you have to investigate this. This number should be high value which will mean that we were able to capture all those SQLs which consumed the DB Time.

Executions Total no, awr report. The sql 2 took 51k seconds and seems to be called in sql ID 1, as their module names are same. Since the SQL 2 insert statement took almost all of the time so we sill focus on this query for tuning. SQL ordered by Gets. SQL ordered by Reads.

In contrast query at number 4 in this table has been executed around awr report times but since reads per execution is low so number 4th query is not the top query to worry about.

SQL ordered by Parse Calls. Tablespace IO Stats. Buffer Pool Advisory. PGA Memory Advisory. So our PGA allocation is way too high, awr report. Shared Pool Advisory. SGA Target Advisory. The SGA target advisory report is somewhat of a summation of all the advisory reports previously presented in the AWR report.

It helps you determine the impact of changing the settings of the SGA target size awr report terms of overall database performance. The report uses a value called DB Time as awr report measure of the increase or decrease in performance relative to the memory change made.

Also the report will summarize an estimate of physical reads associated with the listed setting for the SGA. Buffer Wait Statistics. The buffer wait statistics report helps you drill down on specific buffer wait events, and where the waits are occurring. Enqueue Activities. Awr report Enqueue activity report awr report information on enqueues higher level Oracle locking that occur.

As with other reports, if you see high levels of wait times in these reports, awr report, you might dig further into the nature of the enqueue and determine the cause of the delays. This can give some more information for enqueue waits e.


How to generate AWR report from Oracle Database -


awr report


Jul 09,  · An AWR report outputs a series of statistics based on the differences between snapshots that may be used to investigate performance and other issues. Running a Basic Report. With appropriate licenses for AWR, you may generate an AWR report by executing the following script and pick the two snapshots you want to use for the sample. An AWR report shows data captured between two snapshots (or two points in time). The AWR reports are divided into multiple sections. The HTML report includes links that can be used to navigate quickly between sections. The content of the report contains the workload profile of the system for the selected range of ahjanss.gas: 5. AWR Report • The AWR report is the most well known performance report. • Oracle tuning professionals frequently start their analysis with this report. • AWR report contains much data – but contains no concrete recommendations for action.