Oracle database internals by Riyaj

Discussions about Oracle performance tuning, RAC, Oracle internal & E-business suite.

Archive for the ‘Presentations’ Category

Demos do fail.

Posted by Riyaj Shamsudeen on April 15, 2015

I am an ardent believer of “show me how it works” principle and usually, I have demos in my presentation. So, I was presenting “Tools for advanced debugging in Solaris and Linux” with demos in IOUG Collaborate 2015 in Las Vegas on April 13 and my souped-up laptop (with 32G of memory, SSD drives, and an high end video processor etc ) was not responding when I tried to access folder to open my presentation files.

Sometimes, demos do fail. At least, I managed to complete the demos with zero slides :-) Apologies to the audience for my R-rated rants about laptop issues.

You can download presentations files from the links below.

Session_145_advanced_debugging_using_UNIX_tools

Session_189_Riyaj_Inmemory_internals_files

Posted in in-memory, inmemory, Performance tuning, Presentations | Tagged: , , , , , | Leave a Comment »

IOUG Collaborate 2015

Posted by Riyaj Shamsudeen on March 25, 2015

I will be presenting two topics in IOUG Collaborate 2015 in Vegas. Use the show planner and add my presentations to your schedule :)

Session #189: April 13 Monday 9:15 to 10:15AM Topic: Oracle Database 12c In-Memory Internals. Room Palm B

Session #145: April 13 Monday 12:45PM-1:45PM Topic: Tools and Techniques for Advanced Debugging in Solaris & Linux (mostly live demo). Room Palm B.

Posted in inmemory, Oracle database internals, Performance tuning, Presentations, RAC | Tagged: , , , , , | Leave a Comment »

RMOUG Training Days 2015

Posted by Riyaj Shamsudeen on January 19, 2015

I will be talking in Rocky Mountain Oracle User Group Training Days 2015( http://www.rmoug.org), with live demos (hopefully there will be no failures in the demo). My topics are:

Feb 17: Deep dive: 3:15PM to 5:15PM – RAC 12c optimization: I will discuss RAC global cache layer in detail with a few demos. You probably can’t find these deep Global Cache layer details anywhere else :)

Feb 19: Wednesday: 2:45PM to 3:45PM – Advanced UNIX tools: I will discuss both Solaris and Linux advanced tools to debug deep performance issues.

Feb 19: Wednesday: 12:15PM – 1:15PM – Exadata SIG panel with Alex Fatkulin.

Come to Denver. Come on, it won’t be cold ( I think :) )

Uploading presentation and scripts of the presentation files: RMOUG_2015_Riyaj_RAC_12c_optim files

Presentation files for Unix tools demos: RMOUG_2015_Riyaj_Unix_tools

Posted in 11g, 12c, Presentations, RAC | Tagged: , , , | 1 Comment »

In-memory pre-population speed

Posted by Riyaj Shamsudeen on October 6, 2014

While presenting at Oaktable World 2014 in San Fransisco, I discussed the in-memory pre-population speed and indicated that it takes about 30 minutes to 1 hour to load ~300GB of tables. Someone asked me “Why?” and that was a fair question. So, I profiled the in-memory pre-population at startup.

Profiling methods

I profiled all in-memory worker sessions using Tanel’s snapper script and also profiled the processes in OS using Linux perf tool with 99Hz sample rate. As there is no other activity in the database server, it is okay to sample everything in the server. Snapper output will indicate where the time is spent; if the time is spent executing in CPU, then the perf report output will tell us the function call stack executing at that CPU cycle. Data from these two profiling methods will help us to understand the root cause of slowness.

  1. @snapper.sql out,gather=stw 600 10 “select sid from v$session where program like ‘%W00%'”
  2. Perf tool : perf record -F 99 -u oracle -g sleep 3600

continue reading

Posted in 12c, in-memory, inmemory, Oracle database internals, Performance tuning, Presentations | Tagged: , , , , , , , | Leave a Comment »

Golden rules of RAC performance diagnostics

Posted by Riyaj Shamsudeen on March 20, 2014

After collaborating with many performance engineers in a RAC database, I have come to realize that there are common pattern among the (mis)diagnosis. This blog about discussing those issues. I talked about this in Hotsos 2014 conference also.

Golden rules

Here are the golden rules of RAC performance diagnostics. These rules may not apply general RAC configuration issues though.

  1. Beware of top event tunnel vision
  2. Eliminate infrastructure as an issue
  3. Identify problem-inducing instance
  4. Review send-side metrics also
  5. Use histograms, not just averages

Looks like, this may be better read as a document. So, please use the pdf files of the presentation and a paper. Presentation slide #10 shows indepth coverage on gc buffer busy* wait events. I will try to blog about that slide later (hopefully).

Golden rules of RAC diagnostics paper

Golden rules of rac diagnostics ppt

Scripts mentioned in the presentation can be downloaded here.

scripts

Posted in 11g, Performance tuning, Presentations, RAC | Tagged: , , , , , | 3 Comments »

Hotsos 2014

Posted by Riyaj Shamsudeen on February 25, 2014

I will be presenting in HOTSOS symposium 2014 discussing correct methods to diagnose RAC performance issues. Very surprisingly, even very senior performance engineers make mistakes in their analysis while reviewing RAC issues. Come to my presentation and learn the golden rules of RAC performance diagnostics.

Posted in 12c, Performance tuning, Presentations, RAC | Leave a Comment »

DOUG presentation on dbms_xplan

Posted by Riyaj Shamsudeen on October 22, 2012

Please join us at the DOUG (DALLAS ORACLE USERS GROUP) Oracle Database Forum meeting on Thursday, October 25, 2012 from 5 pm – 7 pm.
Presented by Riyaj Shamsudeen, OraInternals, & Sahil Thapar:

“Out with the old way, Enter dbms_xplan: A Swiss army knife for performance engineers”

Rough outline:
(i) Ability to query access path from memory, AWR repository
(ii) Ability to use cardinality feedback method to understand access plan issues. Few tips from a real world experience will be provided too.
(iii) Ability to understand issues with database links etc.
(iv) Options such as ADVANCED, ALLSTATS etc
(v) Why should you choose dbmx_xplan over tkprof+sql_trace combination?
(vi) Disadvantages of dbms_xplan and a quick introduction to dbms_monitor.

Refreshments sponsored by me :)

Update: Uploading the presentation pdf files. Enjoy :)

dbms_xplan

Posted in Performance tuning, Presentations | Tagged: , , , , | 5 Comments »

June 2012: Jonathan Lewis is coming to Dallas

Posted by Riyaj Shamsudeen on June 15, 2012

Quick note about Jonathan Lewis trip to Dallas: Jonathan Lewis will be presenting two day seminar on two topics, “Beating the Oracle Optimizer” (June 28) and “Troubleshooting and tuning” (June 29th).

The event will be held June 28-29, 2012 at SMU-in-Legacy in Plano, TX.

This is a must-attend event for experienced DBAs and Developers. Especially, if you are planning to upgrade your database/application in the near-future or if you are in the middle of an upgrade, you must attend these two seminars. This seminar series provide enormous value resolving complex Production performance issues.

Click Here for details.

Posted in Performance tuning, Presentations | Tagged: , | Leave a Comment »

All about RAC and MTU with a video

Posted by Riyaj Shamsudeen on May 22, 2012

Let’s first discuss how RAC traffic works before continuing. Environment for the discussion is: 2 node cluster with 8K database block size, UDP protocol is used for cache fusion. (BTW, UDP and RDS protocols are supported in UNIX platform; whereas Windows uses TCP protocol).

UDP protocol, fragmentation, and assembly

UDP Protocol is an higher level protocol stack, and it is implemented over IP Protocol ( UDP/IP). Cache Fusion uses UDP protocol to send packets over the wire (Exadata uses RDS protocol though).

MTU defines the Maximum Transfer Unit of an IP packet. Let us consider an example of MTU set to 1500 in a network interface. One 8K block transfer can not be performed with just one IP packet  as the IP packet size (1500 bytes) is less than 8K. So, one transfer of UDP packet of 8K size is fragmented to 6 IP packets and sent over the wire. In the receiving side, those 6 packets are reassembled to create one UDP buffer of size 8K. After the assembly, that UDP buffer is delivered to an UDP port of a UNIX process. Usually, a foreground process will listen on that port to receive the UDP buffer.

Read the rest of this entry »

Posted in 11g, Oracle database internals, Performance tuning, Presentations, RAC, video | Tagged: , , , , , , , , , , , , , , , , , , | 11 Comments »

My COLLABORATE 12-IOUG sessions

Posted by Riyaj Shamsudeen on April 19, 2012

If you are attending Collaborate 2012, you might be interested in my content-rich sessions below :

Session Number: 326
Session Title: SCAN, VIP, HAIP, and other RAC acronyms
Session Date/Time/Room: Tue, Apr 24, 2012 (10:45 AM – 11:45 AM) : Surf C

Session Number: 327
Session Title: Internals and Performance Boot Camp: Truss, pstack, pmap, and more
Session Date/Time/Room: Wed, Apr 25, 2012 (03:00 PM – 04:00 PM) : Palm A

Hope to see you there!

Update: I am uploading presentation files. Presentations are much more recent than the document :-)

pstack_truss_etc
2012_327_Riyaj_pstack_truss_doc
SCAN_VIP_HAIP_etc
2012_326_Riyaj_scan_vip_haip_doc

Thanks for attending!

Posted in Oracle database internals, Performance tuning, Presentations, RAC | Tagged: , , , , , , , , , , , , | 1 Comment »

 
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