How to detach storage device from running virtual machine in VirtualBox

In this post I want to show how to test what will happen with your cluster if you simply detach shared storage device from it. VirtualBox is great tool for that purpose because you can test such scenario without involving many people or causing any damage.

I am aware that (more...)

Recover corrupted blocks using Flashback Logs

Starting with 11g Oracle can perform block media recovery using flashback logs to get good copies of the blocks.

Flashback database is not enabled by default so first step would be to enable it. When enabled a process RVWR (Recovery Writer) copies modified blocks to flashback buffer. Later this buffer (more...)

Oracle Restart: srvctl fails to start database with error CRS-5010

I’ve installed Oracle Grid Infrastructure on one of my standalone test servers. This software includes Oracle ASM as volume manager and Oracle Restart for managing Oracle components. As recommended, Grid Infrastructure and RDBMS software are installed under different users.

Grid Infrastructure:
RDBMS: 11.2.0. (more...)

Change the SID of the Oracle database using DBNEWID

In this post I will describe how to change Oracle SID using utility DBNEWID. As I can see DBNEWID is available from 9i version but I’ve never heard about it. Till now, I have used procedure where I’m manually editing and re-creating control file.

But I think it’s much better (more...)

Transaction restrictions for Parallel DML on 11g

This will be just short post about restriction on parallel DML that I wasn't aware of. Last week we had to perform quick update of several million rows in very big table. Parallel DML has proven to be the best tool to speed up large DML operation. A DML can (more...)

Kill stuck Oracle process from OS using DBMS_SCHEDULER

Last month we had annoying problems caused by stuck Oracle process holding locks and not releasing them. Every few days one process hangs with status “ACTIVE” and “SQL*Net message from client” wait event.

In that state it holds locks and never releases them. As this is active OLTP database, new sessions arrive wanting those locked resources but they could not get them. So after some time you get lots of waiters and if you don’t react quickly maximum number of processes could be reached. Then your database refuses new connections and you're system becomes unresponsive.

To complicate a problem little (more...)

Listener log missing when Oracle Clusterware starts listener resource script

This post could be interesting for those who are running active/passive failover clusters with Oracle Clusterware used for managing resources. In this case owner of the Clusterware installation is not the same as owner of the Oracle RDBMS installation. Among others, Clusterware is assigned for managing listener resource (start,stop,check).

Till 11g version listener logs were by default written in “$ORACLE_HOME/network/log” but with 11g ADR (Automatic Diagnostic Repository) is introduced and location for listener log is changed. From 11g default location is “$ORACLE_BASE/diag/tnslsnr/<hostname>/listener_<dbname>/trace”.

I’ve noticed that when you start listener as owner of Oracle RDBMS everything is working fine. Listener log (more...)