Friday Feb 21, 2014

dumping SGA

If you are desperately salvaging out data or doing forensics or auditing type of job or just poking around buffer cache or in-memory columnar area and do not want to use oracle tools, I found there are at least 2 ways.

  1. Run gcore on oracle process
  2. You can pipe to od or perl with 'shmcat'. Plus, you can dump shared memory segments selectively.

shmcat | Free Development software downloads at SourceForge.net

This is a simple tool that dumps shared memory segments (System V and POSIX), files and text. It might be useful when you have to debug programs that use shared memory.

Lastly, here are some caveats and foot notes.

  1. I don't think we(oracle) support that instance will run healthy after dumping SGA. Please check with apporopriate channel.
  2. I don't know if any oracle tool can dump SGA in similar way. And I'm afraid Oracle Support won't help finding such tool.
  3. I'm not sure if there's a case when one needs to dump SGA to salvage data even when db is noarchivelog mode and on-line redo logs are accidentally deleted or when all background processes died unexpectedly.

Thursday Feb 13, 2014

RSS proxy by 'netcat' and 'curl'

If you are like me and having problem with your RSS reader,
maybe you can use 'nc'(netcat) and 'curl' combination to work around your problem.

I got this idea by reading this page.

Using netcat to build a simple TCP proxy in Linux - Notes - Tweakblogs - Tweakers

nc -l -p 8080 <fifo | nc tweakers.net 80 >fifo

I admit that I don't fully understand the above line. Maybe I need to read the netcat's source files.
But this works. Here's the script.

#!/bin/bash
# Run this script with nohup and point your RSS browser to localhost:8080
while true
do
  nc -l localhost 8080 < fifo |     curl --silent http://feeds.feedburner.com/OLLRecentActivity?format=xml |       xml_grep --exclude 'channel/item/description' > fifo
done

I don't think this qualifies as 'proxy' because the input is just stubbed out. Also, if your RSS reader is
capable of readling from local file, 'nc' is certainly an overkill.

Lastly, I used 'xml_grep' because I had it installed on my server by chance.
I want to rewrite with XSLT and post here when I have time.

 





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The views expressed on this blog are my own and do not necessarily reflect the views of Oracle.

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