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May 2013

Debugger Dangers – Part 2

About 5 years ago I wrote about the risks that connecting to Oracle processes via debuggers may cause and what are (in my opinion) the safer and less safer options for taking stack samples from running Oracle processes.

In the end of that article I listed different options for getting a stack traces and whether they were safe or not.

For example, ORADEBUG-based process stack traces (DUMP ERRORSTACK, SHORT_STACK and event the process/system state dumps (at level 256 or higher) are not 100% safe – because they alter the execution path of the process they attached to. Your process may crash or get some error if you hit a bug (of course once you patch/fix the bug, you’ll be fine again – until you may hit the next bug).

An example bug is this:

Debugger Dangers – Part 2

About 5 years ago I wrote about the risks that connecting to Oracle processes via debuggers may cause and what are (in my opinion) the safer and less safer options for taking stack samples from running Oracle processes.

In the end of that article I listed different options for getting a stack traces and whether they were safe or not.

For example, ORADEBUG-based process stack traces (DUMP ERRORSTACK, SHORT_STACK and event the process/system state dumps (at level 256 or higher) are not 100% safe – because they alter the execution path of the process they attached to. Your process may crash or get some error if you hit a bug (of course once you patch/fix the bug, you’ll be fine again – until you may hit the next bug).

An example bug is this:

Bug 15677306 : SUNBT6994922 ORACLE LOGWRITER HARD HANG WHEN SIGUSR INTERRUPTS LIBAIO

Star Trek Into Darkness

After yesterday’s visit to see Fast & Furious 6, I went this morning to see Star Trek Into Darkness.

The reviews I read about this pretty much slated it as being extremely self indulgent. Being only an observer of the franchise, rather than a rabid fan, I only noticed a few of the main back references and I didn’t really see them as a bad thing. Instead, I thought they added a little extra dimension to the story.

It’s a full-on action flick more than a sci-fi film really, but worth going to see in my opinion. If they do more of them I will probably go to see them. If they don’t I won’t cry myself to sleep. :)

Fast & Furious 6…

Similar to the Resident Evil franchise, you know exactly what you are going to get when you go to see one of the Fast & Furious franchise. Fast & Furious 6 does not disappoint. It contains a liberal mix of car porn, car chase porn and disaster porn, with the odd bit of comedy thrown in for good measure. It is totally ridiculous, but totally fantastic at the same time.

Summer Cold… Again…

As seems to be the norm for me, the weather has taken a turn for the better and I’ve got a cold. :(

I’d like to say a quick sorry to a couple of people from the BGOUG conference who are waiting for feedback from me about some questions. I will get round to it, but the return to work and this blasted cold have made life complicated.

I spent Friday at work with my face buried in tissues, between necking Covonia. I spent Friday evening until this morning asleep in bed, with occasional periods of sleep in the bath. It’s amazing what 30+ hours in bed can do to a cold and how much damage it can do to your back!

New blog with general Oracle database posts.

Started Oracle database tidbits blog here.

List Exadata Storage Cell disk summary with cellpd.sql and cellpdx.sql scripts

In the previous post I explained how to list Exadata disk layout and topology details with the exadisktopo scripts, in this post I’ll introduce one celldisk overview script, which I use to quickly see the celldisk configuration, specs and error statuses. The cellpd.sql script (Cell Physical Disk) will show the following output:

List Exadata Storage Cell disk summary with cellpd.sql and cellpdx.sql scripts

In the previous post I explained how to list Exadata disk layout and topology details with the exadisktopo scripts, in this post I’ll introduce one celldisk overview script, which I use to quickly see the celldisk configuration, specs and error statuses. The cellpd.sql script (Cell Physical Disk) will show the following output:

List Exadata Storage Cell disk summary with cellpd.sql and cellpdx.sql scripts

In the previous post I explained how to list Exadata disk layout and topology details with the exadisktopo scripts, in this post I’ll introduce one celldisk overview script, which I use to quickly see the celldisk configuration, specs and error statuses. The cellpd.sql script (Cell Physical Disk) will show the following output:

List Exadata Disk Layout and Topology with the exadisktopo scripts

Here are two more Exadata scripts for listing the end-to-end ASM<->Exadata disk topology from V$ASM_ views and from V$CELL_CONFIG. These scripts see both the ASM level layout and the storage cell-level disk topology.

The exadisktopo.sql script shows all disks starting from the ASM diskgroup layer, going deeper and deeper all the way to the OS disk device level in the storage cells. It uses outer joins, so will show celldisks even if there are no corresponding grid disks allocated on them (or if there are no ASM disks using them). It also shows the Flash cards used as flash cache, thus there are no ASM disks on them usually.