One of my customers had a problem with a very slow TRUNCATE TABLE operation on a partitioned table having 22 000 partitions. The problem has raised after a test migration to database 12c. I’ve prepared a little demo to address this issue and show the walkaround for it. Oracle Database 12c (12.1.0.2): Oracle Database 11g […]
A lot companies consolidates databases into one appliance – like for example Oracle Exadata. So you can have a lot of different databases in one physical cluster. And what if I tell you that you can execute any OS command as an oracle user, having just access to a database user with appropriate privileges? What […]
Ludzie z PLUG (http://www.linux.org.pl/) zorganizowali w tym roku pewną wyjątkową konferencję – dBConf (https://www.dbconf.pl/2014/pl/) pod hasłem "Bazodanowcy wszystkich środowisk łączcie się!". Idea zacna i mam nadzieję, że zyska popularność na polskiej scenie konferencyjnej, bo jak często się zdarza, żeby Oracle’owiec pogawędził przy piwku ze specem od DB2 lub SQL Server’a? Wymienił się uwagami z fanem […]
Hash and sort operations are perfomed in PGA. Quoting after the documentation: A sort operator uses a work area (the sort area) to perform the in-memory sorting of a set of rows. Similarly, a hash-join operator uses a work area (the hash area) to build a hash table from its left input. If the work […]
In Oracle 12c (12.1.0.2 to be exact) we can find a cool new feature: Oracle ASM Filter Driver. Quoting after the documentiation: Oracle ASM Filter Driver (Oracle ASMFD) is a kernel module that resides in the I/O path of the Oracle ASM disks. Oracle ASM uses the filter driver to validate write I/O requests to […]
A few months ago I showed how to restore a controlfile, when you have no idea in which backupset is the newest file https://blog.ora-600.pl/2014/04/26/oracle-myth-you-need-dbid-to-restore-the-controlfile/ On last training one of my students asked me, how to locate an appropriate spfile backup after using this trick (the restored database has a different DBID). Well, you can just […]
Sometimes you have to export all metadata for a schema but you have no access to data pump or other tools. SQL Developer can cause a lot of problems with referential constraints. But there is always a good old SQL*Plus 🙂 http://ora-600.pl/oinstall/metadata.sql
http://www.itcertificationmaster.com/become-oracle-certified-master-fun-profit-kamil-stawiarski/
In Oracle 12c there is a possibility to define a PL/SQL function inside the "WITH" clause, which can reduce the context switching overhead. Short example: