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티베로 – The AWR-like “Tibero Performance Repository”

By Franck Pachot

In a previous post I introduced Tibero as The most compatible alternative to Oracle Database. Compatibility is one thing but one day you will want to compare the performance. I’ll not do any benchmark here but show you how you we can look at the performance with TPR – the Tibero Performance Repository – as an equivalent of AWR – the Oracle Automatic Workload Repository. And, as I needed to run some workload, I attempted to run something that has been written with Oracle Database in mind: the Kevin Closson SLOB – Silly Little Oracle Benchmark. The challenge is to make it run on Tibero and get a TPR report.


I’ve downloaded SLOB from:

20c: AWR now stores explain plan predicates

By Franck Pachot

In a previous post I explained this limitation in gathering filter and access predicates by Statspack and then AWR because of old bugs about reverse parsing of predicates. Oracle listens to its customers through support (enhancement requests), though the community (votes on database ideas), and through the product managers who participate in User Groups and ACE program. And here it is: in 20c the predicates are collected by AWS and visible with DBMS_XPLAN and AWRSQRPT reports.

I’ll test with a very simple query:

set feedback on sql_id echo on pagesize 1000

SQL> select * from dual where ascii(dummy)=42;

no rows selected

SQL_ID: g4gx2zqbkjwh1

I used the “FEEDBACK ON SQL” feature to get the SQL_ID.

The Layman’s Term Guide to AWR for Microsoft- Part I

As often as I use the Automatic Workload Repository(AWR) data in my day-to-day job at Microsoft, I think most can imagine how often I’m explaining its value, along with tracing to my Microsoft peeps. Its time to write a post dedicated to the Microsoft crowd who want to understand a bit more about AWR, so hopefully its helpful!

What is the Automatic Workload Repository?

The Automatic Workload Repository, (AWR) had been around since Oracle 10g and requires the diagnostic and tuning management pack licensing to use all of its features in Oracle’s Enterprise Edition database. Versions before had limited collections vs. the modern reporting schema and every subsequent release of Oracle has added to it’s content, which explains the size increase stored in the objects/number of objects in the SYSAUX tablespace.

Purging SQL Statements and Execution Plans from AWR

A previous blog discussed the problem posed by old execution plans that were previously captured by AWR being used by dbms_xplan.display_awr() to describe current executions plans for the same execution plan but displaying the old costs.

Working with AWR: Old Statistics and Costs in Current Execution Plans

This is a blog about a little trap, into which it is easy to fall when analysing performance problems using ASH data and execution plans from AWR.
I will illustrate it with a real example taken from a production PeopleSoft system. A number of sessions were waiting on blocking locks.  I used ASH data to find statements running while holding a blocking lock.  That led me to a particular SQL ID and plan have value.

#eeeeee; border: 0px solid #000000; font-family: courier new; font-size: 100%; overflow: auto; padding-left: 4px; padding-right: 4px; width: 95%;">SQL_ID        SQL_PLAN_HASH_VALUE   ASH_SECS
------------- ------------------- ----------
5st32un4a2y92 2494504609 10670
652mx4tffq415 1888029394 7030
artqgxug4z0f1 8450529 580

Truncate AWR tables (unsupported)

When WRH$ tables grow too large so that they cannot be purged

This is no supported, please look at the My Oracle Support notes for a supported way to purge AWR when going too big, like re-creating AWR (needs to start the database in restricted mode) or purging with the normal procedure (can be long as it runs a delete). And do not copy-paste my statements as this is just an example.

When some tables grow too large, the purge job does not work correctly (because some things like the partitioning are done at the end). Then SYSAUX grows. And worse: the next upgrade may take hours if it has to change something on the AWR tables.

Upgrade time

Here is an example of an upgrade from 11g to 19c which took hours. Here is how I open the upgrade logs with “less” for the Top-10 longest statement execution:


This is another of the blog notes that have been sitting around for several years – in this case since May 2014, based on a script I wrote a year earlier. It makes an important point about “inconsistency” of timing in the way that Oracle records statistics of work done. As a consequence of being first drafted in May 2014 the original examples showed AWR results from and – I’ve just run the same test on to see if anything has changed.


Importing and Working with Exported AWR/ASH data in an Oracle database in a VirtualBox VM

A lot of my performance tuning work involves analysis of ASH and AWR data.  Frequently, I do not have direct access to the databases in question.  Sometimes, I ask clients to run eDB360 on their databases and send me the results, but sometimes I also want to work directly with ASH or AWR metrics.  So, I ask for an export of their AWR repository.
Oracle distributes a pair of scripts in $ORACLE_HOME/rdbms/admin.

CPU percent

A recent post on the ODC General Database forum asked for an explanation of the AWR report values “%Total CPU” and “%Busy CPU” under the “Instance CPU” label, and how the “%Busy CPU “ could be greater than 100%.  Here’s a text reproduction of the relevant sample supplied:

Quick history on database growth

AWR collects segment statistics, and this can be used to quickly understand an abnormal database growth. Here is a script I use to get, from the AWR history, the segments that have grown by more than 1% of the database size, in one hour.

First I must mention that this uses only the part of AWR which is not subject to additional option. This even works in Standard Edition:
------------------------------------ ----------- ------------------------------
control_management_pack_access string NONE