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Visualizing AWR data using python

In my earlier post, I talked about, how tableau can be used to visualize the data. In some cases, I find it useful to query AWR base tables directly using Python and graph it using matplotlib package quickly. Since python is preinstalled in almost all computers, I think, this method will be useful for almost everyone. Of course, you may not have all necessary packages installed in your computer, you can install the packages using install python packages . Of course, if you improve the script, please send it to me, I will share it in this blog entry.

Script is available as a zip file: plotdb.py

Usage:

Data visualization, px qref waits, and a kernel bug!

Data visualization is a useful method to identify performance patterns. In most cases, I pull custom performance metrics from AWR repository and use tableau to visualize the data. Of course, you can do the visualization using excel spreadsheet too.

Problem definition
We had huge amount of PX qref waits in a database:

New Version Of XPLAN_ASH Utility

A new version 4.1 of the XPLAN_ASH utility is available for download.

As usual the latest version can be downloaded here.

This version in particular supports now the new 12c "Adaptive" plan feature - previous versions don't cope very well with those if you don't add the "ADAPTIVE" formatting option manually.

Here are the notes from the change log:

- GV$SQL_MONITOR and GV$SQL_PLAN_MONITOR can now be customized in the
settings as table names in case you want to use your own custom monitoring repository that copies data from GV$SQL_MONITOR and GV$SQL_PLAN_MONITOR in order to keep/persist monitoring data. The tables need to have at least those columns that are used by XPLAN_ASH from the original views

n/a

Rolling upgrads using logical standby database.

Couple of weeks ago there was a Twitter discussion started by Martin Bach (@MartinDBA) about cases for logical standby implementation. A rolling upgrade was mentioned by Tim Gorman (@timothyjgormanas) as one of potential recommendations for using this rare use product. I have been involved in such project in the past and I prepared an instruction and did quite large number of rolling upgrades from 11.1 into 11.2.

There are couple of my “gotchas”

Rolling upgrads using logical standby database.

Couple of weeks ago there was a Twitter discussion started by Martin Bach (@MartinDBA) about cases for logical standby implementation. A rolling upgrade was mentioned by Tim Gorman (@timothyjgormanas) as one of potential recommendations for using this rare use product. I have been involved in such project in the past and I prepared an instruction and did quite large number of rolling upgrades from 11.1 into 11.2.

There are couple of my “gotchas”

Oracle 11gR2 and 12cR1 on Oracle Linux 7 beta

I’ve been having a play with Oracle Linux 7 beta over the weekend. Not surprisingly my first thoughts were to install the Oracle database on it.

As expected, the installations were almost identical or Fedora 19.

Analysing Parallel Execution Skew - Without Diagnostics / Tuning Pack License

This is the third part of the video tutorial "Analysing Parallel Execution Skew". In this part I show how to analyse a parallel SQL execution regarding Parallel Execution Skew.

If you don't have a Diagnostics / Tuning Pack license the options you have for doing that are quite limited, and the approach, as demonstrated in the tutorial, has several limitations and shortcomings.

Here is the video:

Analysing Parallel Execution Skew - Data Flow Operations (DFOs) And DFO Trees

This is the second part of the video tutorial "Analysing Parallel Execution Skew". In this part I introduce the concept of "Data Flow Operations (DFOs)" and "DFO Trees", which is what a Parallel Execution plan is made of. DFOs / DFO Trees are specific to Parallel Execution and don't have any counterpart in a serial execution plan.

Understanding the implications of DFOs / DFO Trees is important as prerequisite for understanding some of the effects shown in the later parts of the video tutorial, hence I covered this as a separate topic.

Note that this tutorial also demonstrates some new 12c features regarding Parallel Execution, in particular how Oracle 12c now lifts many of the previous limitations that lead to the generation of multiple DFO Trees.

Here is the video:

New Version Of XPLAN_ASH Utility

A minor update 4.01 to the XPLAN_ASH utility is available for download.

As usual the latest version can be downloaded here.

These are the notes from the change log:

- More info for RAC Cross Instance Parallel Execution: Many sections now show a GLOBAL aggregate info in addition to instance-specific data

- The Parallel Execution Server Set detection and ASSUMED_DEGREE info now makes use of the undocumented PX_STEP_ID and PX_STEPS_ARG info (bit mask part of the PX_FLAGS column) on 11.2.0.2+

- Since version 4.0 added from 11.2.0.2 on the PX *MAX* DOP in the "SQL statement execution ASH Summary" based on the new PX_FLAGS column of ASH it makes sense to add a PX *MIN* DOP in the summary to see at one glance if different DOPs were used or not