As mentioned in a few blog comments in the past, it’s not the greatest idea to advertise on the web that you’re going on holiday (or vacation if you prefer), given the easy availability of home addresses online. You might as well leave the back door open for the burglars and save the locks being smashed. However, post-dated blog publishing helps, as does everyone not going away together at the same time.<\/p>\n
I’m in London now and have some time on my hands. When I go to sleep at midnight (unusual in itself), I’m likely to wake up at 5 or 6 am. If I’m on holiday, I may drop off again a couple of times and, at a push, can stretch this lie-in until about 8, like this morning. What I wouldn’t expect, unlike your average 14 year old female, is to sleep until 10 – just in time to make breakfast at 10:30! I thought I’d only bought the laptop for an occasional email pick-up, but it looks like I’m going to have a few hours each day. At least I’ll get a proper share of the bathroom in the morning!<\/p>\n
Then again, the fact I bought Cost Based Oracle – Fundamentals<\/a> along might indicate I was expecting this. Hotel rooms help me concentrate. William McIllvaney, one of my favourite authors often books himself into a hotel to finish his books on the basis that they’re so soul-destroyingly anonymous that he has no option but to write because there’s nothing else to do 😉 It helps that I can’t get wireless net access in the bedroom so internet access is going to be limited to the lobby. (Note for friends – that’s why I’m not replying to emails as promptly as usual)<\/p>\n As for the blog title, I hope you’re not expecting a discussion of William Wallace, the Magna Carta or the sources of the desperate situation in the Middle East at the moment, but I’ve been reminded several times recently of the importance of historical perspective in performance tuning. You’ll have to trust me that I’ve been aware of this for a very long time and it’s one of the reasons why I’ve had a few minor arguments on the benefits of Statspack. For the record, I’m a bit of a fan and will get around to defending it one day.<\/p>\n The problem is that you’ll often find you face one of a few different types of performance problems. I’ve ordered these with a vague degree of difficulty, easiest to solve first.<\/p>\n 1) You know you have a problem and can re-create it by running a specific part of the application, be it a user action or batch job. If you have 1, you’re lucky because you can switch on 10046 tracing at level 8 in all current versions of Oracle and see what the job is doing and where the time’s being spent. (I’ll leave the 10g stuff until later.) There are plenty of good 10046 tracing resources around, notably Optimising Oracle Performance<\/a> and the Oracle Press OWI book<\/a>, which I’ve been reading recently. The latter was recommended to me by a few people and I think it’s an excellent companion to the Millsap\/Holt book. As I’ve said before, I rarely recommend Oracle Press books. I’ve bought some that I considered truly awful and even the best are often padded with friendly, chatty language that I’d expect in a blog, not a technical book. I don’t even like the printed layout. This book, however, is one of the best and maybe that’s because there are several authors plus a good half dozen or so excellent technical editors, including people like Oracle’s Graham Wood, who knows as much about this subject as anyone. I still find it a *bit* ‘fluffy’ in places, but I suspect good performance tuning books are tough to write because the subject is deep and wide. If you’re looking for a slightly more down-to-earth, practical ‘how-to’ book to go with Optimising Oracle Performance, this is as good as I’ve come across so far.<\/p>\n Oh, damn, that looks and smells like a short review and I thought I’d banned myself from reviews!<\/p>\n Mmmm, so much for historical perspective. I’ll try to get back on the subject tomorrow …<\/p>\n","protected":false},"excerpt":{"rendered":"
2) You have an intermittent recurring problem which looks system-wide and can’t easily be attributed to a particular part of the application.
3) You had a problem yesterday afternoon and have never had a problem before.<\/p>\n