Database Blog
MySQL Parser Deficiencies
MySQL is a very popular database for many applications. But the parser has some important deficiencies that developers need to be aware of. The parser is inconsistent and not robust in the way that it enforces statement syntax. This may lead to ambiguity and...
Oracle Editioning — Upgrading database applications while in use
Among the features introduced in Oracle 11g is Edition Based Redefinition. This feature enables us to have multiple active versions of database objects in order to facilitiate online application upgrades. Prior to this release, if an application used stored procedures...
Critical Oracle Security and Stability Flaw Discovered
Infoworld today announced that they have been researching a flaw in oracle that can result in the inability to restore your database. Large oracle shops with interconnected databases are most at risk. The problem revolves around oracle's SCN (system change number)....
Total System Failure: Why you should validate your database backup
Every now and then things happen that make us realize how important double checking things can be. I had a recent experience in which four unrelated parties (including me) did the wrong thing regarding one business transaction. If any one of us had done the right...
Database Downtime: Prepare For The Unexpected
Test your Assumptions: Database Backup and Recovery Every now and then something happens that really drives home the need to test and validate the assumptions that we have about the availability of our IT assets. I had an experience this week that brought to mind the...
Query Rewrite: What is MySQL Doing To My Queries?
The Impact of Query Rewrite on MySQL Query Optimization When processing a query, every relational database vendor takes a number of similar steps to parse, validate, and optimize a query. MySQL does the following: Validates the query syntax -- does it use valid...
Database Security: Is Your Database Vulnerable To Internal Attack?
Enforcing Least Privilege To Enhance Database Security The principle of least privilege refers to the practice of ensuring that each individual has only the privilege and access that is necessary to perform their job function. In most IT shops that run an Oracle...
Database Security Issues in the Cloud, Part 2: Regulatory Compliance
As the number of databases moving to public, private and hybrid cloud computing infrastructure increases, security concerns are a significant and growing problem. Organizations will do well to scrutinize the security practices of cloud providers and other third...
Advantages and Disadvantages of Disk-Based Backup and Recovery
Data Backup Advantages & Disadvantages While tape-based backup approaches may still be optimal for long-term data retention, more and more database storage/backup administrators are moving from tape to disk technology for everyday data backup and data recovery....
Why I Avoid Database Hints: a followup
In an earlier blog post about database hints, I gave a number of reasons why I dont like to use hints in SQL queries. Today I wanted to follow up to share one situation where I think hints are OK, even necessary. As described very well in an article in an article by...
Secure The Database, Inside and Out
It has been a relatively short time since I wrote my last post on database security but so many breaches have occurred since then that it seems like much longer. In just the past few months, Sony's gaming system was shut down for two weeks, a nuclear facility in Iran...
Oracle Security: Oracle’s Audit All Command Doesn’t Really Audit All
When attempting to make their Oracle database as secure as possible, many organizations turn on Oracle's auditing feature. Oracle has a very robust auditing feature that enables us to log every action taken in the database. We can audit connections, object creation,...
Bridge the Gap Between Database Security and Application Security
Strong Database Security Today’s database systems have sophisticated security mechanisms designed to enable the protection of data and the tracking of the viewing and modification of the data. For example, Oracle has database roles that govern what database objects a...
Database Security Issues in the Cloud: Part 1
Cloud Database Security Issues And Challenges The benefits of cloud computing, including reduced IT ownership and operating costs and improved resource utilization, are just too good for many organizations to pass up. More and more businesses of all sizes are moving a...
Five Leading Causes of Oracle Database Performance Problems
As we evaluate our clients’ Oracle databases and help them solve problems relating to performance and stability, we see many causes for these issues. However, there are a small number of basic issues that tend to cause problems on the majority of systems. Our Tech...
Remove that Clutter: The Annual Database Security Audit and Cleanup
As the New Year begins, many of us take the beginning of a new calendar year as a cue to to clean out and shred our old files and reorganize our storage spaces so that we have room for all the new supplies and equipment we will need in the new year. We do this because...
Oracle RAC is Now Supported on VMware
In a recent change to its long-standing policy, Oracle Corp. will now support its customers running Oracle Real Application Cluster (RAC) software on VMware platforms in certain circumstances. This positive move for customers was announced in a document titled...
Oracle Performance Tuning — Trust but Verify
During an Oracle Performance Tuning engagement in the past, I learned a valuable lesson about validating the information that you are given during a database evaluation. About ten years ago, a client called me with a serious problem. They had just completed...
Oracle Performance Tuning: Periodically reorganize database objects
One of our Oracle Consultants shared a story with me today that illustrates the importance of periodically reorganizing objects in an oracle database. He was examining a performance problem with a very small oracle table. The table had only 154 rows!. Hardly a large...
Oracle Security — Data Masking using Enterprise Manager
Database administrators often have to provide test data sets to developers, QA teams, or UAT teams. This can be done manually creating test data sets, which can take a very long time especially when the goal is to stress test a new system and a large amount of data is...