Or: “Why we should be happy about Adaptive Cursor Sharing”
Premier Support for 10g R2 ended in July 2010, and Extended Support will end in July 2013, 11gR2 is widely used, and 12c is on the horizon. Maybe it’s time for writing a kind of obituary for my first Oracle love, and to spread a salutary anecdote Tom Kyte told me years ago.
There is a company of the smaller kind with around one hundred people working there, but very profitable. Their business depends on a busy (near-) real time booking system – the one that needs one of those smaller OLTP database systems most of you will know. As users usually do, they are not aware that this system does exist at all.
One rainy summer Friday, suddenly all booking user masks were dead slow. They had no full time DBA, and the on-site application supporter didn’t find the cause, short of his impression that it must be the database, what else? But it was a short Friday, and the users did not worry too much, just worked up old stuff you never finish during normal business. On Monday, the issue was forgotten.
Some weeks later, on the first Thursday in fall, the same issue occurred. Now it was middle of the week, the business impact was more serious, and management winced. The application supporter was forced to look deeper, and now he was sure: The database! Next day, everything was fine. Having a so-called “one time issue”, they postponed closer and expensive investigation to “next time, if it happens again at all”.
Two days later, they were nearly-frozen again, and in the following weeks they experienced more and more bad days like that. The IT department didn’t find anything, so they started pulling the usual straws of any kind. Random rebooting, hardware pimping, and so on. The most useful measure they did, was to collect information about everything unusual and write it down. The secretary who was told to do so disagreed that it’s useful, and for a joke, she started adding today’s weather on top of the daily recording. To her surprise, and what made her the hero of those days, she always had to start each bad day’s report with bad weather news: “rain”, “thunderstorm”, “snowing”. This was the point when IT started asking for reinforcements, and they asked me to come on-site on the next bad day.
I hadn’t to wait long, three days later I was called to come ASAP and thus, arrived at the company in heavy morning rain. First thing they told me, that they found out that afternoon rain does not impact the performance. Crazy folks, aren’t they?