Tales From A Lazy Fat DBA

Loves all databases! – Its all about performance, troubleshooting & much more …. ¯\_(ツ)_/¯

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Archive for October, 2017

What’s new in coming few days here on FATDBA ….

Posted by FatDBA on October 24, 2017

Some of the performance troubleshooting that i have done using few of the specialized tools/scripts – SYSTEMTAP, CALIPER, STRACE, PTRACE, Few of the Profilers, Representation using PGraph, FlameGraphs and few of the beautifully written scripts/tools from legends like Brendan Gregg (www.brendangregg.com/), Luca Canali (cern.ch/canali) etc.

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DB Sick/Hung/Slow :( …. How to troubleshoot using ‘Real Time ADDM’ ??

Posted by FatDBA on October 24, 2017

The new emergency monioring feature of “Real Time ADDM” or RT ADDM (Performance Menu within the EM Console) of Enterprise Manager Cloud provides a new feature which allows the DBAs to connect with the non responsive or hang/stalled database. Now someone might ask that this was earlier achieved using ‘-prelim’ option which allows the execution of ORADEBUG commands but if you remember it was not that flexible and allows only limited arguments like hanganalyze, ashdump etc.

This all new feature of 12c is one step ahead as it directly connects (Using the light weight lock/latch-free connection) with the SGA area and hits the hang Analysis and Active Session History tables and also helps to view the blockers etc. and other in-memory performance statistics.

So this is quite helpful at times when we have …
– Sick Systems
– DB is very slow
– DB Hung due to any contention for resources etc.
– DBAs are unable to login to Database.

So before that moment when we are all set to bounce the database there is this option available to take a look inside the database to understand the system.

Hope It Helps
Prashant Dixit

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12c all new Parallel Upgrade utility.

Posted by FatDBA on October 24, 2017

With Oracle Database 12c enters the all new Parallel Upgrade Utility, catctl.pl. This utility exchanges the catupgrd.sql script that was used in earlier releases.
Although you can still use the catupgrd.sql script, it is vilipended starting with Oracle Database 12c and will be removed in future releases.
Oracle urges database upgrades be performed with the new Parallel Upgrade Utility, catctl.pl.

If you choose to run the catupgrd.sql script instead of running catctl.pl, doing so now requires an additional input argument as follows:

SQL> @catupgrd.sql PARALLEL=NO

If you run catupgrd.sql without the parameter, then Oracle displays the following error message:

NOTE:

The catupgrd.sql script is being deprecated in the 12.1 release of Oracle Database. Customers are encouraged to use catctl.pl as the replacement for catupgrd.sql when upgrading the database dictionary.

cd $ORACLE_HOME/rdbms/admin
$ORACLE_HOME/perl/bin/perl catctl.pl -n 4 catupgrd.sql

Refer to the Oracle Database Upgrade Guide for more information.

Hope It Helps
Prashant Dixit

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