Using one Client with multiple Oracle wallets

16. October 2020 Uncategorized 0
Last week I got a task from one customer, to set up the Oracle Client, which could seamless connect to multiple databases in the Oracle Cloud, for which we need the Oracle wallet. Let’s say there is one database in the EU region Frankfurt, and the second one is in the EU region Zurich. I ...

Database Upgrade using autoupgrade tool

This time I had to upgrade a SE2 12.2 database running on Windows on Azure Cloud to the version 19.3. I do not have such setup in my lab, so I was a little bit sceptical about it, and it will turn out – with a reason. So, I read a ton of a articles ...

You should take care about statistics!

Ever since Oracle introduced the CBO (Cost Based Optimizer) there were some performance issues, mostly because of missing or staled statistics in the database. I stopped to count the cases, when I just gathered fresh statistics for some table(s) and voilà – the query runs 100x faster! I will mention just one of the latest ...

Wrong result returns when Subquery is unnested

A couple of days ago I got a request to take a look at one SQL query, which obviously returns the wrong result. The database version is 12.2 running on Windows on Azure Cloud. Simplified for the demo purpose it looks like this – the query returns 1 and 2, but it should return 1, ...

LMS0: terminating the instance due to error 481

15. December 2016 Uncategorized 1
One production RAC database has been upgraded to 12c and everything went fine for a couple of months, but suddenly after some time, one instance got terminated with the error messages: LMS2 (ospid: 17238): terminating the instance due to error 481 ORA-00481: LMON process terminated with error   The analysis was not so easy. We ...

DataPatch: patch 23177536: The database must be in upgrade mode <- are you serious!?

29. September 2016 Uncategorized 2
Today I applied the latest patchset 12.1.0.2.160719  (July 2016) and afterwards I executed datapatch tool, but got a really stupid error: [oracle/ACME1@acme01 OPatch]$ sqlplus / as sysdba SQL> select  PATCH_ID, PATCH_UID, VERSION, STATUS, DESCRIPTION      from DBA_REGISTRY_SQLPATCH      order by BUNDLE_SERIES;       no rows selected [oracle/ACME1@acme01 OPatch]$ ./datapatch -verbose SQL Patching tool version 12.1.0.2.0 ...

Upgrade to 12c: ORA-38753: Cannot flashback if there is tablespace with FLASHBACK=NO !

Yesterday at customers site I had to upgrade one 11g database to 12c and stumbled upon a tricky issue. As I already upgraded a many dozens of databases, I think (or I thought at least), that I am pretty familiar with the whole process: planning, preparation, check list, pre-upgrade tasks and so on… But, yesterday ...

Unified Auditing: some gotchas to be aware of!

Database should be offline when you are enabling pure Unified Auditing or you will get this error: ORA-00600: internal error code, arguments: [krsh_fsga_sgaq.ds_not_found], [], [], [], [], [], [], [], [], [], [], [] By default, in 12c version the auditing runs in mixed-mode, which means you can combine traditional auditing with unified auditing. There ...

“Slow” system & ORA-00445: background process “DIAG” did not start after 120 seconds ?

Since I am currently checking all Oracle systems at the customers site, I thought at first sight, that almost all of them are overutilized or wrong configured, because everything seemed so sloooooow… Especially the new logins and creating of the new processes were a way too slow – more than 5 seconds! Sometimes I waited ...