I have faced an issue with a program (who uses a old Java 1.6 runtime) and tires to connect to an Oracle Database, the program sometimes connects in few seconds, sometimes need minutes and sometimes fails (and in the database alert logs appears an ORA-3136 due a client connection time-out). The issue are not related […]Read more "Slow or failed connections to Oracle Database using Java"
In this entry I try to explain some basic facts about character sets in Oracle Databases and the most current issues with them. The databases can store different types of information, numbers, dates, characters, raw data (data with a format know by the owner but not necessary by the database) among others, but internally all […]Read more "Oracle character set basics"
I have some Ubuntu virtual machines for do my little labs, and to execute them I use VirtualBox, one good and Open Source virtualization platform. One of the first things we do after install a new Ubuntu is enable ssh access to them, due is far easy for me to work on terminal windows from […]Read more "Enable SSH access on Virtualbox Ubuntu Virtual Machine"
If you need to connect to a windows system from your Ubuntu environment one of the easiest methods is using “rdesktop” an open source Linux tool who “mimics” the Microsoft Terminal Client Windows application. To use this tool you only need some sort of graphics desktop on your Ubuntu system and install the rdesktop pakage: […]Read more "Terminal Server connections from Ubuntu"
Inside most installations of Oracle Clusterware 11g exists an “Berkeley DB” database used to store system performance data. This database also exists on the initial release of 12g (184.108.40.206) database, and after that (from 12c patch1 or 220.127.116.11) this “Berkeley DB” is replaced by an Oracle DB (called “Grid Infrastructure Management Repository”) This database is […]Read more "Cluster Health Monitor Database size, or who is filling my clusterware volume?"
The expdp and impdp tools appeared in Oracle 10g many years ago, from that moment these were the “supported” way to export and import information from Oracle Databases (in Oracle proprietary format). In this post I’ll try to explain the most misunderstood/not known points of this tools. An export is not a backup. Well, so […]Read more "Oracle expdp and impdp hints"
For those of us who work with 12c Databases the task of recovering dropped tables or older versions of them from RMAN backup is an “automated task” executed by RMAN. It is only necessary one command like this: Under the hood RMAN: Creates an auxiliary instance Restores all necessary data files for the affected tablespaces […]Read more "Recover a table from a RMAN backup on Oracle Database 11g"