Steve Callan

Cascade is one of those clauses (or keywords) which seems to permeate many areas within the Oracle RDBMS. Generally speaking, when an event or action includes a cascade clause, the intent is that good things will follow. Good things, in this context, means that extra work will be done for you. To illustrate the point, […]

Some words in Oracle have special meaning. Maybe not to you, but then you’re not the one having to parse, execute and fetch what you type. To be more precise, the “some words” in the first sentence can be categorized as reserved words and keywords. Within the keywords category, context comes into play because a […]

In the days of yore, we had rollback segments. In order to use a rollback segment in a transaction, either by letting Oracle choose one or by explicitly setting/naming one, the rollback segment first had to be specified in the initialization parameter file. With the advent of Automatic Undo Management (AUM), Oracle abstracts the management […]

As mentioned in a previous article, there is more than one approach or tool to use in a “tuning opportunity.” Ideally, the opportunity occurs before code has gone into production, but as we’re all aware of, a lot of time spent on tuning code takes places in production. Context is always important to keep in […]

A user deletes data from a table and commits it. How do you retrieve that data? If using a version of Oracle with flashback technology – AND you are made aware of the error while the undo information is still retained – that’s not so much of a problem. If running in noarchivelog mode, and […]

Depending upon what you’re investigating when it comes to performance, one tool may be all you need to answer the question at hand. For more complex questions, chances are several tools may be needed. Tools, in this scenario, can consist of using an explain plan, monitoring sessions and diagnostic information as can be observed using […]

One of the basic facts or concepts that virtually all DBAs know is that truncating a table to remove data is faster than deleting the same data. But beyond that truism, there are subtle differences that when taken into account, can help improve the overall performance of a job or process. Truncation and deletion each […]

I like to recommend good products or finds from time to time, and the subject of this recommendation is Tim Hall’s Oracle PL/SQL Tuning Expert Secrets for High Performance Programming (published by Rampant TechPress). Books on PL/SQL, like books on other topics related to Oracle, range from the just so-so to what can be called […]

The internal workings of the Oracle RDBMS are a marvel to behold. Think about all of the things you do know with respect to what it takes to issue a select statement, perform an update, or create a table. Latches, locks, serialization, caching, pinning, flushing, checkpointing, sorting, space management, undo, redo, and the list goes […]

We all know the path up the physical and logical chains of an Oracle database. A fairly typical statement in most database administration books states that a tablespace is where the physical meets the logical. Further, these books go into great detail about the building blocks of each chain. The lowest starting point on the […]

Today’s journey takes on a trip into Oracle’s data dictionary, specifically, the dictionary part or aspect of it. It’s interesting and informative to take a peak under the covers and see how Oracle, (the product, that is), is put together. Aside from trying to reverse engineer things, looking at the underlying components presents an “If […]

Depending on your environment, working with and between Windows and UNIX can be somewhat problematic. It seems that no two workplaces are the same when it comes to the network file system. Two of the more commonly seen problems include not being able to get a GUI tool (e.g., Oracle Universal Installer) to display and […]