Posts by Christo Kutrovsky
I’m heading to Oracle OpenWorld in just a few hours! This year I ended up with two exciting sessions. I would invite you to pre-register, but they are already packed! You are welcome to join the waiting list, and I highly suggest you to do so if you like them.
Interval partitioning – the ability to create partitions on the fly was introduced in 11g. When the feature came out, there were several nasty bugs. One such particular “limitation” has to do with parallel group by on the partition key. If you want to see just that part, skip towards the end, but I think reading the whole blog will offer some insights in how Oracle Parallel Query works.
Since I was using a version of 11 already, an experimental upgrade was not a problem. With the BE (boot environments) feature, one could boot into any version safely. BE is an awesome feature. Need to install a patch? Install into a boot environment – any problems reboot into the old environment. BEs leverage ZFS snapshots to create a clone of your boot disk, install any patches onto it and allow you to switch flawlessly between the two.
Unfortunately, there is no easy way to monitor what’s in the Smart Flash Cache. Oracle only provided a “list flashcachecontent” command in the cellcli tool, it has no summarization options, and only displays object numbers. So I wrote this handy tool which lets you query the cell flash content on all cells, similarly, you can query the buffer cache (db_cache) contents in v$bh.
Blogging from the Speaker Ready room which is now suited on the balcony overlooking the exhibition. I must say that I like the new location. Not only it is closer to the action, but allows you to oversee who is hanging out over the exhibitors. There’s been a number of interesting sessions, but it’s little things here and there that I learn that provide some real value. Here’s a few examples
This is just a quick post to note that I’ve corrected my blog on Storage Indexes here, after a follow up blog from Kerry Osborne indicating an error on my part.
As a follow up from my previous post on Exadata Design, where I question the use of dimensions for certain attributes in data warehouses, I figured I should test whether HCC works with tables that have more than 255 columns, It does. Here’s my test case.
Oracle Exadata V2 is a very well balanced database machine combined with smart and innovative software. One of these innovative features is the Storage Index – a game changing feature in my opinion.As with any feature, there are intended use cases, limitations and caveats. Use it right, and amazing performance gains can be achieved. Use it wrong, and nothing will happen. This is what is great about storage indexes in particular. They are there, without any overhead. It’s only a question of how to leverage them, in addition or combination withevery other feature that Oracle Exadata has to offer.
Many have expressed the deepest desire to see OPT_ESTIMATE documented, but that never happened. I’ve just troubleshot a problem and used this hint a lot during my “what if” scenario testing, and found this hint to be quite useful. Thus, I decided to document it here on the blog. I will come back and update this blog as I discover new parameters, and feel free to suggest what you’ve found in the comments. If you can, include an example to illustrate usage.
Here are the slides from my presentation at RMOUG 2010. I am not sure how much sense all this will make without my comments. We may do it in a webinar if there is sufficient interest. Regardless I will probably be doing it again at some point in the future.
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