Posts Tagged ‘RAC performance’
Posted by Riyaj Shamsudeen on January 28, 2017
I will be speaking about the following topics in Rocky Mountain Oracle User group Training days (RMOUG, Denver) February 7-9, 2017.
Come to my presentations and say Hi to me 🙂
1. RAC Cache Fusion Internals and Performance Tuning RAC Wait Events – Tuesday 3:15PM to 5:15PM
2. Index and Redo Internals – Wednesday 4-5PM
3. Database In-Memory Internals – Thursday 11:15-12:15PM
RMOUG training days 2017
Here are the scripts and presentations as promised 🙂 Of course, no implied or explicit warranty.
index_and_redo_internals scripts zip
Disclaimer: These are my opinions based upon research and data, it doesn’t reflect the views of my employer.
Posted in 12c, inmemory, Oracle database internals, Performance tuning, Presentations, RAC | Tagged: oracle performance, RAC performance, RAC presentations, RAC training, rmoug, rmoug 2017 | Leave a Comment »
Posted by Riyaj Shamsudeen on March 24, 2016
Over the last many years, some of you have invited me to attend conferences in India, and talk about Oracle RAC and performance. I have not had an opportunity to make it to conferences in India, until now 🙂
I am excited to announce that I will be participating in OTN sponsored Oracle ACE Director’s tour in India (April 23rd to May 2nd 2016), and presenting ( with deep dive demos ) about RAC, performance, and in-memory. This is a golden opportunity for you to learn some of the internal stuff that I talk about in my class too.
Refer http://otnyathra.com for further details.
I am also excited to be in the tour with Connor McDonald, Biju Thomas, Sai, and many others. Don’t forget to send an email to Sai, the conference rooms will fill out quickly.
Did I mention deep dive demos? 🙂
Update 1: Updating the presentation slides and scripts. Do ask if I miss any script that you are looking for 🙂
Posted in 12c, Performance tuning, Presentations, RAC | Tagged: oracle performance, RAC performance | 5 Comments »
Posted by Riyaj Shamsudeen on November 18, 2015
Thanks for coming to my presentations in RAC day at Dublin, Ohio. Please find the presentation files below. Hopefully, I will get video files and upload that here too.
OOUG presentation files and scripts
md5 checksum of the zip file is:
Posted in Oracle database internals, Performance tuning, Presentations, RAC | Tagged: oracle performance, RAC, RAC performance | 3 Comments »
Posted by Riyaj Shamsudeen on October 22, 2015
I will be talking about RAC and performance in-depth, with lots of demos, in a RAC day training with Ohio Oracle User group on Nov 16,2015 Monday. Venue for the presentation is Dublin, Ohio.
Agenda for the day:
08:00a – 09:00: Registration / Breakfast
09:00a – 09:15: Announcements -Introduction of the speaker
09:15a – 10:30: Underpinning for Oracle RAC and Clusterware
10:30a – 10:45: Break
10:45a – 11:45: RAC cache fusion internals
11:45a – 01:00: Lunch
01:00p – 02:00: RAC Performance tuning Part 1 – Wait events and object tuning
02:00p – 02:15: Break
02:15p – 03:30: RAC performance tuning Part 2 – locks, library cache locks etc.
03:30p – 03:45: Member Announcements, Gift Drawings
Please RSVP to the co-ordinators so that you will have a seat 🙂
OOUG RAC day
Posted in Oracle database internals, Performance tuning, Presentations, RAC | Tagged: oracle performance, RAC, RAC performance, RAC performance myths | 1 Comment »
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: gc buffer busy, RAC performance, RAC training, rmoug | 1 Comment »
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.
Here are the golden rules of RAC performance diagnostics. These rules may not apply general RAC configuration issues though.
- Beware of top event tunnel vision
- Eliminate infrastructure as an issue
- Identify problem-inducing instance
- Review send-side metrics also
- 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.
Posted in 11g, Performance tuning, Presentations, RAC | Tagged: gc buffer busy, oracle performance, RAC performance, RAC performance diagnostics, RAC performance myths, RAC performance scripts | 3 Comments »
Posted by Riyaj Shamsudeen on September 9, 2013
I blogged about DFS lock handle contention in an earlier blog entry. SV resources in Global Resource Directory (GRD) is used to maintain the cached sequence values. I will further probe the internal mechanics involved in the cached sequences. I will also discuss minor changes in the resource names to support pluggable databases (version 12c).
Let’s create an ordered sequence in rs schema and then query values from the sequence few times.
create sequence rs.test_seq order cache 100;
select rs.test_seq.nextval from dual; -- repeated a few times.
Sequence values are permanently stored in the seq$ dictionary table. Cached sequence values are maintained in SV resources in GRD and SV resource names follows the naming convention to include object_id of the sequence. I will generate a string using a small helper script and we will use that resource name to search in the GRD.
SELECT DISTINCT '[0x'
|| '],[SV]' res
FROM dba_objects WHERE object_name=upper('&objname')
AND owner=upper('&owner') AND object_type LIKE 'SEQUENCE%'
Enter value for objname: TEST_SEQ
Enter value for owner: RS
Read the rest of this entry »
Posted in 12c, Oracle database internals, Performance tuning, RAC, weird stuff | Tagged: oracle performance, pluggable database, RAC internals, RAC performance, SV resource, weird stuff | 2 Comments »
Posted by Riyaj Shamsudeen on September 8, 2013
A quick note, Expert Oracle RAC book co-written by me is available now: Expert Oracle RAC 12c. I have written about 6 chapters covering the RAC internals that you may want to learn 🙂 I even managed to discuss the network internals in deep, after all, network is one of the most important component of a RAC cluster.
Posted in 12c, Oracle database internals, Performance tuning, RAC | Tagged: oracle performance, performance, RAC internals, RAC performance | Leave a Comment »
Posted by Riyaj Shamsudeen on June 1, 2012
This is a quick note about reverse path filtering and impact of that feature to RAC. I encountered an interesting problem recently with a client and it is worth blogging about it, with a strong hope that it might help one of you in the future.
Environment is 184.108.40.206 GI, Linux 5.6. In a 3 node cluster, Grid Infrastructure (GI) comes up cleanly in just one node, but never comes up in other nodes. If we shutdown GI in first node, we can start the GI in second node with no issues. Meaning, GI can be up in just one node at any time.
System Admins indicated that there are no major changes, only few bug fixes. Seemingly, problem started after those bug fixes. But there were few other changes to the environment /init.ora parameter change etc. So, the problem was not immediately attributable to just OS changes.
Read the rest of this entry »
Posted in Oracle database internals, Performance tuning, RAC | Tagged: "has Disk HB, advanced RAC training, but no Network HB", cssd not joining cluster, RAC performance, reverse path filtering, rp_filter | 11 Comments »
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: cache fusion mtu, fragmentation and reassembly, gc lost packets, ipfrag_high_thres, ipfrag_low_thres, ipfrag_time, Jumbo frames, MTU, MTU=9000, oracle performance, RAC internals, RAC performance, RAC presentations, RAC training, RAC video, RAC videos, RDS, UDP vs tcp, wireshark | 13 Comments »