Author Archives: mgogala

About mgogala

I am a consultant with an extensive Oracle DBA experience. I have worked on very large databases. I have worked with OPS and RAC since its inception.I am also a published book writer, having published two books about PHP. This blog is about the challenges and adventures in my professional life. Sorry, no family pictures here.

SCOTT/TIGER for SAP Hana

SAP Hana is becoming increasingly popular these days. It comes with its own demo schema, STUDENT. However, being an old Oracle hack, I ported the SCOTT schema from Oracle to SAP Hana. Every Oracle DBA has a bunch of queries … Continue reading

Posted in Uncategorized | Leave a comment

Finding the trace files

In Oracle versions before 12c, it was necessary to resort to complex magic to find out the location of the process trace file. One of the most famous recipes is probably the one invented by René Nyffenegger and available here: http://www.adp-gmbh.ch/ora/misc/find_trace_file.htmlContinue reading

Posted in Uncategorized | 2 Comments

ACFS 12.2 Quirks with defragmentation

I have a 12.2 RAC cluster in my lab, on two virtual machines. Checking out what acfsutil can do, I figured out that it can supposedly do defragmentation: [grid@rac1 ~]$ acfsutil defrag -help Usage: acfsutil [-h] command … # (Version … Continue reading

Posted in Uncategorized | Leave a comment

RAC 12.2, part 2

Well, today was an interesting day. My ASM, configured with so much effort, stopped working: root@rac1 grid]# . ~grid/.bashrc [root@rac1 grid]# crsctl start ohasd CRS-4640: Oracle High Availability Services is already active CRS-4000: Command Start failed, or completed with errors. … Continue reading

Posted in Uncategorized | Leave a comment

RAC 12.2

I am in the process of installing RAC 12.2. The installation procedure has undergone a significant change, for the better. It’s now much easier to install it. However, memory and disk requirements have skyrocketed. I needed to allocate 10GB of … Continue reading

Posted in Uncategorized | Leave a comment

Rename Pluggable Database

I stumbled upon a convenient way to rename a pluggable database: SQL> alter system enable restricted session; System altered. SQL> alter database rename global_name to test12.home.com; Database altered. SQL> alter session set container=cdb$root; Session altered. SQL> select name from v$pdbs; … Continue reading

Posted in Uncategorized | 1 Comment

12c: OPTIMIZER_DYNAMIC_SAMPLING=11

Oracle 12c has a new feature related to optimizer dynamic sampling. The new level 11 is supposed to put the dynamic sampling on auto pilot and make the statistics available to other users. However, as soon as this was set, … Continue reading

Posted in Uncategorized | Leave a comment