Relational DBMS used to be fairly straightforward product suites, which boiled down to:
- A big SQL interpreter.
- A bunch of administrative and operational tools.
- Some very optional add-ons, often including an application development tool.
Now, however, most RDBMS are sold as part of something bigger.
With cellcli you can run the calibrate command, this will measure the performance of your harddisks and flashcards. It will eventually report to you the throughput and amount of IOPS that was measured during the calibrate, it will also report to you which luns are not performing up to par.
As part of my Cloud Control journey I encountered a strange problem where I got the following error for few Exadata Storage Server (cell) targets:
Metric evaluation error start - oracle.sysman.emSDK.agent.fetchlet.exception.FetchletException: em_error=Failed to execute_exadata_response.pl ssh -q -o ConnectTimeout=60 -o BatchMode=yes -o StrictHostKeyChecking=no -o (more...)
Thanks to all those who came to my session "Are Indexes Unnecessary in Exadata" at Oracle Open World 2013. Considering it was late afternoon of the last day of the conference, especially after the appreciation concert, it was a pleasure to see a packed room. Judging by the interaction I (more...)
I heard a strange report from a client late last week - they weren't getting any smart scans on their Exadata - a data warehouse, no less (and we checked to see if cell_offload_processing was set to true). Queries would run normally, but for some reason, the "cell physical IO (more...)
You have bought Exadata after spending a fortune and more importantly after convincing everybody in the organization and in your family that this is the ultimate resource machine which hosts the world’s best database, Oracle 12c. You are not off the mark with those statements, though one might term them bit exaggerated. The point is […]
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A while back, I noticed this session in the Open World 2013 content catalog. I didn't think much of it at the time, other than that it had a catchy title. The other day, I downloaded the latest Exadata deployment utility via the OneCommand tool. I noticed something a little (more...)
I have seen several clients who are struggling to decode page allocation failures on Exadata, in this post i will try to explain how to read the backtrace. The following is an anonymized client case where page allocation failures are leading up to a node reboot.
Jan 1 11:58:02 dm01db01 (more...)
Just a quick reminder - I'll be presenting my "Getting Ready for Exadata" seminar in London on July 1. We'll cover various topics on what you need to know before you purchase an Exadata and how to manage one of these systems on a daily basis. We'll have lots of (more...)
An Oracle Exadata Full Rack consists of 8 DB compute nodes. Oracle has shifted the strategy to patching the exadata in 18.104.22.168.0 onwards to using Yum as the method of patching. the Quarterly Full Stack does not include the DB Compute nodes patches anymore. So that (more...)
Rene Kundersma at Oracle just published a nifty new utility named dbnodeupdate.sh that will assist with the sometimes-cumbersome process of updating the compute nodes in an Exadata environment. Starting last year with 22.214.171.124.0, Oracle introduced yum updates for the Exadata compute nodes. Previously, each Exadata (more...)
I’ll be co-speaking with Tyler Muth at E4 and we will be talking about Performance Visualization… some of you may already know that I’m really a big fan of Tableau and just to give you an example on what the tool can do I’ve consolidated all the different viz that (more...)
The basic idea behind the Exadata Hybrid Columnar Compression (hereby referred as EHCC) is to reprise the benefits of column based storage while sustaining to the fundamental row based storage principle of Oracle database. Oftentimes the databases following column based storage claim that comparatively they needs less IO to retrieve (more...)
When using Locally Managed Tablespaces
(LMT) with variable, system managed extent sizes (AUTOALLOCATE
) and data files residing in ASM
the Allocation Unit (AU)
size can make a significant difference to the algorithm that searches for free extents.The corresponding free extent search algorithm when searching for free extents >= the AU size
seems to only search for free extents on AU boundaries
in order to avoid I/O splitting
.Furthermore the algorithm seems to (more...)
Here is an interesting limitation to Exadata Smart Scans
- if more than 254 columns
from a table (not HCC compressed, more on that in moment) need to be projected, Smart Scans for that particular segment will be disabled
and Exadata will fall back to conventional I/O. This means that the number of columns in the projection clause can make a significant difference
to performance, since only Smart Scans allow taking advantage of offloading
I have announced my webinar on Oracle ZFS Storage Appliance for Exadata Backup & Recovery in NYOUG DBA webinar series. You can download webinar slides and voice recod from NYOUG web site
In Friday December 14, 2012 at 12:00 PM -1:00 PM EDT I will be giving a webinar for NYOUG SIG with the following abstract
When it comes to the backup and recovery infrastructure of the Exadata Database Machine, conventional solutions often have only limited performance to keep up with Exadata throughput, whereas Oracle ZFS Storage Appliance can be configured as a very fast, capable, and easy-to-manage backup and recovery solution for any Exadata environment. In this session Husnu Sensoy will describe some of the configuration possibilities of the ZFS Storage Appliance to create a flexible backup and recovery environment for Exadata, (more...)
I’ve been working a lot with graphing DB and OS metrics in R. I find it especially useful in Exadata POVs (proof of value) to gather and graph the oswatcher vmstat files for the compute nodes and iostat for the cells. For an example, take a look at this graph (PDF, 168 KB) of what [...]