by Maciej Tokar | Aug 17, 2016 | Oracle 11g R2, Oracle 12c R1, Oracle Database, Other
Playing recently a little with one of the databases having as a task improvement of its overall performance I had noticed a group of queries with hundreds of child cursors. Let me show you one of them. Looks more or less like this – logic doesn’t matter at...
by Maciej Tokar | Jul 18, 2016 | Oracle 11g R2, Oracle Database, Other, Patching
I was playing with the query published by Syed Jaffar Hussain to list installed patches using DBMS_QOPATCH package that I described here http://dba24.pl/2016/07/12/how-to-list-the-db-patch-details-in-sql/. Unfortunately I came across some problems and would like to...
by Maciej Tokar | May 1, 2016 | Installation, Oracle 11g R2, Oracle 12c R1, Oracle Database, Real Application Cluster
This is short but I hope useful post on how to check if your Oracle software for database has got the RAC option enabled, how to enable and disable the option How to quickly check if you have RAC enabled Change directory to your database software...
by Maciej Tokar | Apr 2, 2016 | Linux, Oracle 11g R2, Oracle 12c R1, Oracle Database, Redhat 7
I had a nice Oracle DB crash recently on one of my environments with RHEL 7.1. Do you wonder why? Some OS updates had been installed by the OS admin and my DB got crazy. See what had happened ORA-27157: OS post/wait facility removed ORA-27300: OS system dependent...
by Maciej Tokar | Apr 2, 2016 | Oracle 11g R2, Oracle 12c R1, Oracle Database
Why are HugePages incompatible with Automatic Memory Management in Oracle Databases? Just few words to answer this straightforward question: You cannot use Automatic Memory Management (AMM) while implementing HugePages, because AMM works on dynamic SGA and PGA tuning....
