Jonathan Lewis

Browsing around over the weeend, I came across this blog. I didn’t spend much time reading through the material, but at first sight I got the impression that a number of the articles might be useful to people who were starting to experiment with RAC systems  and could do with some step by step guidance when [...]

Here’s a summary of a question that appeared on the Oracle Forum some time ago: I had been seeing frequent log file switching (resulting in “checkpoint not complete” reports) at night when some export dumps have to occur simultaneously, so I increased my redo log file sizes from 5MB to 10MB. I now have a user who [...]

I’ve just been sent an email about an event in Edinburgh next month, featuring Chris Date in a two-day seminar titled “A Relational Approach to SQL” - plus a half-day forum on the third day. The event is organised by the e-Science Institute, with assistance from Oracle. Thanks for the assistence from Oracle, the cost to [...]

It’s been over a year now since Don Burleson published his “biased test cases” article. He removed it from his website after I had pointed out that his behaviour was likely to damage his reputation more than it would damage mine - at which point I deleted all the associated comments from my blog. Sadly, [...]

I posted a summary of page hits a little while ago when the WordPress statistics hit 750,000 page views, and commented at the time that a couple of the most popular items seemed to be related to the types of issue you get when you upgrade to 10g. Well, it occurred to me this morning to [...]

I don’t really have anything to do with XMLDB (beyond the fact that it’s an application built in an Oracle database, of course, and subject to tuning and bugs just like any other application), so it was nice to get an email last night from Marco Gralike telling me that the next release of XMLDB [...]

[Back to part 9] The following question appeared some time ago on the Oracle Forum: Event Waits Time(s) Avg Wait(ms) % Total Call Time Wait Class CPU time [...]

You may have noticed that I keep my blogroll quite short - I have a few names on there more or less permanently, and have a few “guest” slots that I change from time to time. At present, Cary Millsap isn’t on the list - though he has been one of the “guest” names in the [...]

If you make use of the blogroll I’ve got at the right of this page, you’ve probably visited Greg Rahn’s blog a few times. If so, you may have noticed that Don Burleson has decided to pitch in and throw some mud around because he feels threatened by Greg’s choice of example in a posting about [...]

Shortly after I published the previous post, I received an email from an old client who reminded me of a problem he had had with empty index blocks, the solution we had used (which was a coalesce) and an update on how things had changed in the latest releases of Oracle. Strangely, I was sure I [...]

Have you ever created an index on a column with a name like “last_update_date” – or maybe even a function-based index on “trunc(last_update_date)” ? You can probably guess the purpose of the column from its name – but could you also guess what state that index is going to be in a few weeks after you’ve [...]

There are a few expressions in the industry that irritate me - not necessarily for good reason but simply because they sound like the extremes of pretentiousness and marketing put together.  (Pretentious, moi !) For example: “root cause analysis”, “holistic methods”  and so on - it’s all those little ways of saying “we’re doing just the same [...]

A question about reporting data one page at a time came up on the Oracle Database Forum a couple of days ago – it’s a class of question that is becoming more common as more applications get web-based front-ends, but this example was a little more subtle than usual – so I spent a few [...]

Another landmark - this morning the blog counter reached 750,000. It’s taken a little longer to get the third 250,000 than it did the second - but given how little I’ve written over the last few months it’s still a pleasant surprise. WordPress supples some interesting stats, so I’ve copied up the top three entries for [...]

The agenda for the UK Oracle User Group annual conference is now available. If you like the look of the “Masterclass” events on the Friday, remember that you have to pre-book them.

Struggling as I am to find time to write items for the blog, I was pleased to get an email yesterday from someone who had discovered an interesting little feature of pl/sql programming and wanted to pass it on to me. I thought that other people (PL/SQL developers in particular) might find it useful, so I [...]

I’m still struggling to catch up after my holiday - it always amazes me how much time it takes to prepare for, and then recover from, a break, but if the client needs something done it has to be done - so the weeks before and after a holiday are always a little frantic. Still, just [...]

I’ve just come back from a couple of weeks wind-surfing - so I’ve spent the last few days recovering from sundry injuries and catching up on email. One of the emails raised a point about deterministic function which made me realise that I still had a few items that I had written for Howard Rogers’ Wiki [...]

A recent post on the OTN forum asked: I was wondering is there any fast method for updating 8 million records out of 10 million table? For eg : I am having a customer table of 10m records and columns are cust_id, cust_num and cust_name. i need to update 8m records out of 10m customer table as follows. update customer [...]

If you’ve ever looked at view v$sql_bind_capture, you’ve probably seen that (at least in 10.2) it allows you to see the actual values for bind variables that have been used with an SQL statement. For a long time I had assumed that this view was capturing the bind values used when the optimizer peeked at the variables [...]