OEL/RHEL 7 – firewalld

How cool is getting Linux. Hope it won’t look like Windows soon. If they put a butterfly or shiny window in the “start menu” I’m out of the game.
The “new” firewalld is cool and dynamic, but my servers are square, boring and static. Maybe if I’m using RHEL/OEL 7 in my laptop it will be worthy. For me this is just one unneeded layer of complexity on top of iptables, but this is just my opinion. Maybe you can find it useful in some cases, maybe if you use your server for wifi client or whatever. To be honest, I like the reload function, which is not bad, but still not a big deal. You can achieve this with iptables as well. Of course here is easier.
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Optimizer statistics – parse time statistics aggregation

It’s getting harder and harder to find time for writing. Anyway, this post stays from a long time in my drafts so, I think is time to finish and post it. That one is the last one from the optimizer statistics series. For now, of course :)

After describing the horror around the way that Oracle is handling the global statistics, it’s time to take a look what happens if we don’t have global statistics at all.

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Optimizer statistics – Gathering Statistics and Histograms

It’s such a mess with those histograms and statistics that I had to rewrite this post at least ten times. It’s such a mess that I still cannot believe how poorly maintained the global statistics are and how badly created the histograms are. Because of this mess and the depth of the topic this post is a bit longer than usual, but I find it really useful and I think it can give answers to many questions.

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Optimizer statistics – Stale percentage and partitioning

Oracle is full of surprises, dbms_stats and optimizer statistics as well. That’s why I’m starting a new series named “Optimized statistics” in which I’ll cover some gathering and usage issues related to them.

As we know 11g has a cool feature which tracks how much data we had changed in our objects and if it’s more than the 10% /default/ it marks our statistic as stale. This is really useful because we don’t have to waste time scanning objects without having changed reasonable amount of data in them. But is it working for partitions? Well, not really, not till today.

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