ORA-01917: user or role ‘PDB_DBA’ does not exist

I manually created a container database (CDB) in my Linux 6.4 based virutal machine. After creating it, I tried to create a pluggable database but got following error:

SQL> select instance_name,status from v$instance;

---------------- ------------
cdbtest          OPEN

1 row selected.

SQL> show con_name


SQL> select * from cdb_pdbs;

      DBID    CON_UID GUID                             STATUS    CREATION_SCN
---------- ---------- -------------------------------- --------- ------------

Amazon S3 to Glacier – Cloud ILM

Falling in love with Kate Upton is easy but more easier is to be swept off your feet by information lifecycle management (ILM) in the Amazon Web Services (AWS). Simple, easily-configurable, fast, reliable, cost effective and proven are the words which describe it.

Pythian has been involved with ILM for a long time. With various flavors of databases and systems, Pythian has been overseeing creation, alteration, and flow of data for a long time until (more...)

Last Successful login time in 12c

One cool small yet valuable feature in Oracle 12c is the display of 'Last Successful login time'. If authentication is from the OS level, then it isn't shown. A small demo is as follows:

[oracle@targettest ~]$ sqlplus '/ as sysdba'

SQL*Plus: Release Production on Sun Sep 6 18:22:00 2015

Copyright (c) 1982, 2013, Oracle.  All rights reserved.

Connected to:
Oracle Database 12c Enterprise Edition Release (more...)

d in Vertica

A quick neat way to list down important and oft-needed information like names of databases, schemas, users, tables, projections etc. We can also use patterns with the 'd' to narrow down the results. Let's see it in action:

Connect with Vertica vsql:

vsql  -U dbadmin -w vtest -h -p 5433 -d vtest

 Welcome to vsql, the Vertica Analytic Database interactive terminal.
Type:  h or ? for help with vsql commands
g (more...)

Creating User Schema Table and Projections in Vertica

Vertica is a an exciting database with some real nifty features. Projections is a ground breaking unique feature of Vertica which dramatically increases performance benefits in terms of querying and space benefits in terms of compression.

Following test commands are impromptu sesssion in which a user is being created, then a schema is created, and that user is authorized on that schema. Then a table is created with a default superprojection and then a projection (more...)

Mongostat ; A Nifty Tool for Mongo DBA

One of the main Mongodb DBA's task is to monitor the usage of Mongodb system and it's load distribution. This could be needed for proactive monitoring, troubleshooting during performance degradation, root cause analysis, or capacity planning.

Mongostat is a nifty tool which comes out of the box with Mongodb which provides wealth of information in a nicely and familiar formatted way. If you have used vmstat, iostat etc on Linux; Mongostat should seem very familiar.


Shift Command in Shell Script in AIX and Linux

Shell in Unix never ceases to surprise. Stumbled upon 'shift 2' command in AIX few hours ago and it's very useful.

'Shift n' command shifts the parameters passed to a shell script by 'n' numbers to the left.

For example:

if you have a shell script which takes 3 parameters like:

./mytest.sh arg1 arg2 arg3

and you use shift 2 in your shell script, then the values of arg1 and arg2 will be lost (more...)

Recover Oracle Undo Tablespace without Backup

Woke up with an issue regarding a Oracle 10.2.0 database on Linux complaining about an Undo file on startup.

sqlplus '/ as sysdba'

SQL*Plus: Release - Production on Fri May 22 20:11:07 2015

Copyright (c) 1982, 2006, Oracle.  All Rights Reserved.

Connected to an idle instance.

SQL> startup pfile='init.ora'
ORACLE instance started.

Total System Global Area 2801795072 bytes
Fixed Size                  2075504 bytes
Variable Size            1275069584 bytes

LPAR and Oracle Database

What is LPAR?

LPAR stands for Logical Partitioning and it's a feature of IBM's operating system AIX (Also available in Linux). By abstracting all the physical devices in a system, LPAR creates a virtualized computing environment.

In a server; the processor, memory, and storage are divided into multiple sets. Each set in a server consist of resources like processor, memory and storage. Each set is called as LPAR.

One server can have many LPARs operating (more...)