Log Buffer #458: A Carnival of the Vanities for DBAs

This Log Buffer Edition covers various useful tips and tricks from blogs for Oracle, SQL Server and MySQL.


  • pstack(or thread stack) for Windows to diagnose Firefox high CPU usage
  • With the ever-changing browser landscape, we needed to make some tough decisions as to which browsers and versions are going to be deemed “supported” for Oracle Application Express.  There isn’t enough time and money to support all browsers and all versions, each with (more...)

Log Buffer #457: A Carnival of the Vanities for DBAs

This Log Buffer Edition begins with some great blog posts from Oracle, goes through SQL Server and then ends with MySQL.


  • Ruby-oci8 is a ruby interface for an Oracle Database.
  • Another python graph – one wait event.
  • This article compares FBL and HDL – two of the commonly used data loading tools in Fusion HCM to highlight key differences and similarities.
  • Better Data Modeling: Customizing Oracle Sql Developer Data Modeler (#SQLDevModeler) to Support Custom Data (more...)

Log Buffer #456: A Carnival of the Vanities for DBAs

This Log Buffer Edition covers many aspects discussed this week in the realms of Oracle, SQL Server and MySQL.


  • Oracle and Informatica have a very close working relationship and one of the recent results of this collaboration is the joint project done by Informatica and our Oracle ISV Engineering team to test the performance of Informatica software with Oracle Database 12c In-memory on Oracle SPARC systems.
  • The only thing you can do easily is (more...)

Log Buffer #455: A Carnival of the Vanities for DBAs

What better to do during the holiday season than to read the Log Buffer? This log buffer edition is here to add some sparkle to Oracle, MySQL and SQL Server on your days off.


  • Ops Center version 12.3.1 has just been released. There are a number of enhancements here.
  • Oracle R Enterprise (ORE) 1.5 is now available for download on all supported platforms with Oracle R Distribution 3.2.0 / R-3.2. (more...)


There might be a situation where executing some DDL in pluggable database may cause the following error:

ORA-65040: operation not allowed from within a pluggable database

This error could occur if a tablespace is being dropped from within PDB and this tablespace is a former default tablespace having some of the system objects. Even system objects cannot be moved with simple alter statements from within PDBs.

So in order to move these objects from within (more...)

Got Published in AUSOUG’s Foresight Online Spring 2015

AUSOUG's Foresight Online Spring 2015 Edition is the premier publication by Australian Oracle User Group.

Following are highlights of this edition:

  • President's Message
  • DBA Article: Automated Testing of Oracle BPM Suite 12c Processes with SOAP UI - Peter Kemp, State Revenue Office, Victoria
  • DBA Article: Best Practices for Oracle on Pure Storage
  • Apps Article: Performance Review Data Capture - Brad Sayer, More4Apps
  • DBA / Dev Article: Database Developers – Feeling (more...)

Sharding in Oracle 12c Database

Sharding for Oracle DBAs is still pretty much an alien or pretty new concept. In the realms of big data, this term is being used quite extensively though.

What is Sharding in simple words:

Sharding is partitioning. Horizontal partitioning to be exact.

Sharding means partitioning a table rows on basis of some criteria and storing that partitioned rows of table (i.e. a shard) on different database servers. These database servers are cheap low commodity (more...)

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...)

Showing Interval Partitons Code in DBMS_METADATA.GET_DDL

-- If you want to display the system generated partitions as part of the CREATE TABLE DDL, then set the EXPORT parameter of the dbms_metadata to true.

-- The default behavior of "DBMS_METADATA.GET_DDL" is that it does not show Interval Partitions created by the system for interval partitioned tables and indexes.

-- In the case of Interval Partitioning, New Partitions are created automatically when corresponding row is inserted.  This newly created partition information (more...)

Oracle Querayable Patch Interface

Starting from Oracle 12c, from within the SQL patching information can be obtained. A new package DBMS_QOPATCH offers some really nifty procedures to get the patch information. Some of that information is shared below:

To get patch information from the inventory:

SQL> select xmltransform(dbms_qopatch.get_opatch_install_info, dbms_qopatch.get_opatch_xslt) from dual;

Oracle Home      : /u01/app/oracle/product/12.1.0/db_1
Inventory      : /u01/app/oraInventory

The following is an equivalent of opatch lsinventory command at the OS level:

SQL> select (more...)

Steps to Blackout Agent of Cloud Control 12c

1) Set the environment to the cloud control agent. You can agent name from /etc/oratab file.

myserver: $ . oraenv
ORACLE_SID = [ORCL] ? agent12c

2) Check which targets are being monitored by the cloud control agent on this server:

myserver: $ emctl config agent listtargets
Oracle Enterprise Manager Cloud Control 12c Release 4 
Copyright (c) 1996, 2014 Oracle Corporation.  All rights reserved.
[MYSERVER, host]
[MYSERVER:3872, oracle_emd]
[ORCL, oracle_database]

3) Check if there is any existing (more...)

Exadata Vulnerability

This Exadata vulnerability is related to glibc vulnerability. A heap-based buffer overflow was found in glibc's __nss_hostname_digits_dots() function, which is used by the gethostbyname() and gethostbyname2() glibc function calls.

A remote attacker able to make an application call either of these functions could use this flaw to execute arbitrary code with the permissions of the user running the application.

In order to check if your Exadata system suffers from this vulnerability, use:

[root@server ~]# ./ghostest-rhn-cf. (more...)