Recently, at a customer site, I discovered the Attunity connector 1.1 for Oracle. The customer uses this connector to transfer data from Oracle to SQL Server using Integration Services (SSIS) and informed me that performances are greatly improved. So I decided to post a blog about this connector and perform a benchmark between Attunity connector and Microsoft OLE DB provider for Oracle.

Last week, Oracle Ace Director Jonathan Lewis held an Oracle Optimizer Workshop at dbi services Basel Area. I would like to share some of the key learnings of this really interesting exchange I experienced together with my colleagues.

Oracle has introduced three new caching features in its Oracle 11g release:

• Query result cache
• Client OCI result cache
• PL/SQL function result cache

In this posting, I will present the query result cache feature.

Oracle SQL Developer and Data Modeler are becoming more and more popular as they are both cost-free and available on many Operating Systems (Linux/Unix,Windows and Mac) with different installation types: "This zip does not include JRE" or "This zip file includes the JRE". On linux, the choice is limited because the only version available doesn't include Java Runtime Environment. And it's an RPM !! So what... In this post I will provide all information required to install and run these tools on an Ubuntu machine.

MySQL 5.6 offers improved partition maintenance through "partition exchange". Even if not yet available, dbi services performed some tests on the MySQL Community Edition 5.6.2 m5 release (still under development).

Performance tunning is becoming a key focus for most of the DBAs. In scope of the "dbi services labs", I made some tests on functions which can help improving these, but which are not always well-known. Today's article is going to describe one of these, the SPARE COLUMNS.
The property of Spare columns is not the most used in client environment that we have seen.
This article present a script to find the potential columns that can have the sparse property with the usage restrictions to make a space tuning in your database and especially for Data Warehouse (DWH).

The database example that we used, is AdventureWorksDW2008R2.

Last week at a customer site, we experienced an excessive redo log generation rapidly filling up the FRA (Flash/Fast Recovery Area) with archivelog files. This eventually caused the database to crash.

During the last weeks, I experienced an uncommon bug during upgrade of security sensible databases: The upgrade process was sticking for hours on the script c1101000.sql which tried to fill the column DBID with the database DBID of the tables AUD$ and/or FGA_LOG$ (auditing and fine grained auditing tables).

Sometimes, you need to modify the statistics of a table. There are various reasons: either for the performance analysis or because the execution plan changed. Oracle offers two methods: statistics restore or statistics export. Both are in the dbms_stats package.

While discussing with some tuning gurus, I was made aware about this feature. It is not so far from the adaptive cursor sharing perfectly described in Chris Antognini's blog: http://antognini.ch/papers/BindVariablePeeking_20090718.pdf

This feature compares the real execution (number of returned/actual rows - "A-rows") with some expectations (number of expected rows - "E-rows") and chooses another plan for the next executions if the difference between the expectation and the actual result is too big. "Cardinality Feedback" is not well documented in the Oracle documentation.

Since Oracle 11.2, Oracle provides ORION in the RDBMS binaries (in ${ORACLE_HOME}/bin). ORION - ORacle Input Output Numbers - is an I/O calibration tool allowing to simulating and testing I/O performances an Oracle database would be confronted with. ORION basically supports four kinds of database activities based on either small or large I/O. ORION can, as any respectable I/O simulation tool, generate an adapted workload using a given percentage of reads and write operations.

You do not want to install or configure swingbench, load runner etc. - just to test the performance of your I/O system based on filesystems? Then Flexible I/O is the right tool for you. This post provides an overview.

As you certainly already have heard, Oracle 11g comes with a new feature called “Instance caging”. This feature allows Oracle DBAs to easily manage Oracle Instance CPU consumption. How does it work? Quite easily ... see below.

Index compression comes from Oracle 8i and has quite the same mechanism as table compression. Index compression eliminates duplicate column values in the leaf blocks. Let's see how it works:

MySQL Workbench provides several necessary tools in order to manage a MySQL environment. MySQL Workbench 5.2 is available for Windows, Mac, and Linux platforms. It encapsulates three main functionalities: SQL Development, Data Modeling, and Server Administration.

Have you ever noticed strange figures while collecting the Oracle optimizer system statistics ? If so, you need to provide the optimizer with the correct number, as explained in this posting.