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Dennis Ritchie RIP
There can be few scientists who have contributed so much to the world as Dennis Ritchie. Completely anonymous to the world at large, and to far too much of the computing fraternity too, his involvement...
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Oracle Timestamp Processing – mildly annoying
I was writing a small piece of SQL this morning which I needed to account for daylight savings time correctly. All of my databases run in UTC, so a quick foray into using TIMESTAMP AS TIME ZONE seemed...
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Implicit Conversion Errors
A while ago, I failed over a database (as planned) to it’s Dataguard copy, and of course everything worked as expected. Everything, that is, except a couple of reports which get sent directly from the...
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SYSTIMESTAMP INTERVAL Processing
…or how to calculate dates in Oracle. This is just a quick post to try to encourage the use of the INTERVAL function when adjusting (sys)timestamps (or dates). I thought this would be better expressed...
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Exposing the Oracle Alert Log to SQL
I’ve been spending some time working in Apex recently, building a small app to draw together the monitoring of application and infrastructure components into a single easy-to-visualise tool. As part of...
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SQL Developer insight
When using SQL Developer, there is a feature called Completion Insight which help you write SQL and PL/SQL in the SQL Worksheets. It will auto-pop helpful things, like object name when typing a SELECT...
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Oracle’s Locking Model – Multi Version Concurrency Control
Filed under: Administration, Programming Tagged: acid, concurrency, lock, multi version concurrency control, mvcc, optimistic, oracle, pessimistic, redo, undo
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Doing it properly?
When giving a presentation last year about how much a DBA should do to get to the bottom of a problem; in a discussion between Martin Widlake, myself, and the audience we amusingly concluded that we...
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Developers Killing Sessions
When you end up spending a far great a percentage of your day than seems sensible killing off Java connections that Developers have carelessly left lying around, locking objects all over the place, you...
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Adding NOT NULL Columns with DEFAULT values – 11G
In Oracle, if we add a column to a table which is NOT NULL, we are allowed to do it directly, in a single statement, as long as we supply a DEFAULT value to populate any pre-existing rows. This would...
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Developers
Just a small Sunday night anecdote with a wider point. I, or maybe a colleague, recently received an update statement from a developer. Now, this developer is long of tooth and is well versed in the...
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Locking Privileges in Oracle
What permissions do you need to lock rows on an Oracle table? What about to lock the whole table? It’s not quite as much as you may think! Lets have a couple of users; schema_owner and user1 SQL>...
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