Kerry Osborne’s Oracle Blog

I had an interesting little project this morning. Of course it takes longer to write it down than to do actually do it, but it was kind of interesting and since I haven’t done a post in quite some time (and it’s the day before Thanksgiving, so it’s pretty quite at the office anyway) I decided to share. One of the Enkitec guys (Tim Fox) was doing a performance comparison between various platforms (Exadata using it’s IB Storage Network, Oracle Database Appliance (ODA) using it’s direct attached storage, and a standard database on a Dell box using EMC fiber channel attached storage). The general test idea was simple – see how the platforms stacked up for a query that required a full scan of a large table. More specifically, what Tim wanted to see was the relative speed at which the various storage platforms could return data. The expectation was that the direct attached storage would be fastest and the fibre channel storage would be slowest (especially since we only had a single 2G HBA). He tested ODA and Exadata and got basically what he expected, but when he went to test the database on the Dell he was surprised that it was actually faster than either of the other two tests. So here’s some output from the initial tests: First the Exadata. It’s an X2 quarter rack with one extra storage server. Note that we had to set cell_offload_processing to false to turn off the Exadata storage optimizations, thus giving us a measurement of the hardware capabilities without the Exadata offloading.

> !sqlp
sqlp
 
SQL*Plus: Release 11.2.0.2.0 Production on Wed Nov 23 11:08:28 2011
 
Copyright (c) 1982, 2010, Oracle.  All rights reserved.
 
 
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
Data Mining and Real Application Testing options
 
SYS@DEMO1> @uptime
 
INSTANCE_NAME    STARTUP_TIME      CURRENT_TIME         DAYS    SECONDS
---------------- ----------------- ----------------- ------- ----------
DEMO1            07-NOV-2011 12:37 23-NOV-2011 11:08   15.94    1377058
 
SYS@DEMO1> set sqlprompt "_USER'@'EXADATA'>' "
SYS@EXADATA> 
SYS@EXADATA> ! cat /etc/redhat-release
Enterprise Linux Enterprise Linux Server release 5.5 (Carthage)
 
SYS@EXADATA> ! uname -a
Linux enkdb03.enkitec.com 2.6.18-194.3.1.0.3.el5 #1 SMP Tue Aug 31 22:41:13 EDT 2010 x86_64 x86_64 x86_64 GNU/Linux
 
SYS@EXADATA> alter session set "_serial_direct_read"=always;
 
Session altered.
 
SYS@EXADATA> alter session set cell_offload_processing=false;
 
Session altered.
 
SYS@EXADATA> set autotrace on
SYS@EXADATA> set timing on
SYS@EXADATA> select count(*) from instructor.class_sales;
 
  COUNT(*)
----------
  90000000
 
Elapsed: 00:00:43.01
 
Execution Plan
----------------------------------------------------------
Plan hash value: 3145879882
 
----------------------------------------------------------------------------------
| Id  | Operation                  | Name        | Rows  | Cost (%CPU)| Time     |
----------------------------------------------------------------------------------
|   0 | SELECT STATEMENT           |             |     1 |   314K  (1)| 00:00:02 |
|   1 |  SORT AGGREGATE            |             |     1 |            |          |
|   2 |   TABLE ACCESS STORAGE FULL| CLASS_SALES |    90M|   314K  (1)| 00:00:02 |
----------------------------------------------------------------------------------
 
 
Statistics
----------------------------------------------------------
          1  recursive calls
          0  db block gets
    1168567  consistent gets
    1168557  physical reads
          0  redo size
        526  bytes sent via SQL*Net to client
        524  bytes received via SQL*Net from client
          2  SQL*Net roundtrips to/from client
          0  sorts (memory)
          0  sorts (disk)
          1  rows processed
 
SYS@EXADATA> set autotrace off
SYS@EXADATA> @fss
Enter value for sql_text: select count(*) from instructor.class_sales
Enter value for sql_id: 
 
SQL_ID         CHILD      EXECS   AVG_ROWS     AVG_ETIME       AVG_CPU       AVG_PIO      AVG_LIO SQL_TEXT
------------- ------ ---------- ---------- ------------- ------------- ------------- ------------ ----------------------------------------
b2br1x82p9862      0          1          1         43.00          3.16  1,168,557.00    1,168,567 select count(*) from instructor.class_sa
 
Elapsed: 00:00:00.08

So the test on the Exadata took 43 seconds to read and transport roughly 1 million 8K blocks. The same test on the ODA looked like this: Continue reading ‘Tuning Oracle to Make a Query Slower’ »

I will be participating in an Exadata Virtual Conference which has been organized by Tanel Poder on August 3rd and 4th. This conference will follow the same format as the one Tanel and I did last year with Jonathan Lewis and Cary Millsap. It will be two half days which should provide some flexibility for people with busy schedules. The online format allows all participants to interact directly via chat while the speakers are presenting and then via voice during question and answer sessions. This is a great opportunity to talk to some guys that have done a bunch of work with Exadata. Andy Colvin will be discussing patching which has been problematic for some shops. Andy has done more patching than anyone I know. Randy Johnson will be discussing Resource Management on Exadata which is a key to successful consolidation projects. I will be talking about how Smart Scans work under the covers and covering techniques for determining when and where they are (or are not) occurring. Tanel will be covering in depth tuning and diagnostic techniques specific to Exadata. Of course, Randy, Tanel and I collaborated on the upcoming Apress book, Expert Oracle Exadata, which should be out a couple of weeks before the conference. Here’s a link to the page with all the conference details:

Exadata Virtual Conference

Note that there is a discount for early registration. I hope to see you there.

Well my lone abstract submission didn’t get selected at Open World this year. But apparently they have a second chance system where you can “Suggest a Session” and users can vote on which papers they’d like to see on the agenda. I went ahead and suggested “Tuning Exadata” – It sounds like something you shouldn’t have to do, but remember that Exadata is not an appliance that has few or no knobs to turn. It has all the power and options of an Oracle database and there are certainly things that you can do wrong that will keep Exadata from performing at its best. So the paper is about how you can know for sure whether Exadata is doing what it should and how to coerce it if you need to.

The mix.oracle.com site where this voting is supposed to take place is a little difficult to navigate (in my humble opinion) so here’s a direct link to the page where you can see the abstract (and vote if you deem it worthy). ;)

Tuning Exadata

You will have to log in with your Oracle Single Signon account (what you use for My Oracle Support – or Metalink for the old guys) or I think you can create an separate account if you want. By the way, Andy Colvin has submitted an abstract for a talk on Exadata Patching, which should be very informative if it gets picked. He’s done more Exadata patching than anyone I am aware of. Here’s a link to his abstract:

Rolling with the Punches – Adventures in Exadata Patching

There will undoubtedly be many deserving abstracts. For example, several of my OakTable brethren have suggested sessions as well. So please look around the site for others of interest as well. You can vote for as many as you want.

We’ve been joking around at the office about whether the Exadata X2-8 model has actually been observed in the wild. Some of the guys have been affectionately referring to it as Sasquatch because we’ve never actually seen one. Well we actually got our hands on real one today.

Not as pretty as the X2-2, but as long as it’s fast it doesn’t really matter what it looks like I guess. Thanks to Andy Colvin for the iPhone snap. We’ll be doing some testing with it soon so stay tuned. By the way, we’ve got our T-Shirts on order:

I spoke at an Oracle marketing event in San Antonio last night. Here is a link to the promotional page for the event (it will probably disappear soon). I promised to make a copy of my slides available so here it is: