Author: Christo Kutrovsky

The Answer to Free Memory, Swap, Oracle and Everything

I have submitted an abstract for my new presentation about linux/unix memory and Oracle to the Rocky Mountain Oracle Users Group for the Training Days in Denver on February 14-15, 2007. I pilot tested it at the Ottawa Oracle User Group in June. The feedback was good and since then I have kept developing the presentation. Soon to be submitted for HotSos 2007.

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Oracle: How to move a table to another schema?

A client asked me, “How can I move a table to another schema in Oracle?” The quick answer I gave him is, “not possible”. You have to rebuild it via “create table as select”. You might ask, justifiably, why would you want to do that anyway? His problem was that the application has been split into 2 parts, and he wanted to have separate schemas for each part, to ensure that there is no cross-schema table access.

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Eurotrip Vacation For Me

It’s time for vacation for me.

I am off to Europe and then vising home – Sofia, Bulgaria. I will be back in 4 weeks. Yes I did earn to have a long vacation, and yes, Pythian is really nice in allowing me to have it all at once.

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RMAN in 10g

There’s always these little things that you discover when you read the manuals. For example the “duration” option for RMAN backup. It looks very neat, and is actually in RMAN from 10g Release 1.

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ZFS – VM for Storage?

James Foronda sent a link to his blog entry about silent data corruption in an Oracle-l discussion. He points out a new file system called ZFS that has self-healing features.I read all the slides and it really looks like something cool to try out. It has some features similar to Oracle’s ASM, such as dynamic adding of disks, self balancing etc. It’s fully transactional, supports snapshots, online everything. Auto striping (not sure how this would work). Very feature rich.

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Oracle 10g R2 RAC – vip on wrong interface

I was installing RAC, and during the clusterware install I picked up the wrong interfaces for public and private. What had happened was I had a 10.x.x.x IP on both eth0 and eth1, which was messing up the routing. The solution? Simply modify the VIP in the cluster configuration.

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ASM multi-disk performance

If you have the ability to combine disk spindles at both the SAN level and Oracle (ASM) level, which one is better? Should you combine all your spindles on the SAN and present 1 big disk to OS and give that to ASM? Or should you present each individual disk spindle to ASM and let ASM do the mirroring? The disk group with 2 disks is slower! Those results are consistent, and confirmed with diagnostic output from iostat. You may start to wonder why would 2 be slower then 1. It should be twice as fast!

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Day two at Collaborate 2006 (Christo)

After I actually woke up I found myself attending a session about LogMiner by Chet Watmough. Log Miner in my opinion is a vastly under-used utility. It has such great versatility. Chet showed some techniques to add additional logging. By inserting the client info information into a dummy table, just to produce a record in the redo stream, he can identify who did what.

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First Day at IOUG 2006

So I made my decision and went to “RAC & ASM best practices” presented by Kirk McGowan of Oracle. I wanted to see how far the documentation / common sense was from what will actually work. It wasnt that far from the docs, which is good. It means Oracle got it right.

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Reading The Docs About Stuff You Know

I needed to change the undo_retention parameter in a 10gR2 database. Unfortunately I forgot whether the parameter was in seconds or minutes, and I wanted to see what the default was. So I open up the docs, go into the Reference guide and get the info I need from the top few lines. I wanted to set undo_retention to some large value in order to use flashback. So I decided to read if they were any notes about setting this too large. I started reading the notes. I’ve read this in the past, so didn’t expect anything new. Then I read the following: “For fixed-size undo tablespaces, the system automatically tunes for the maximum possible undo” What? Fixed size undo vs autoextend undo ? That’s new!

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