"gc buffer busy", "gc current block busy", "enq: TX- index contention" - How about you interconnect? Do you use Gigabit NIC? - Use Partition Table/Index - that can reduce index contention. - Increase SGA - Update? - Increase INITRANS - How about PCTFREE? Good Luck Surachart Opun http://surachartopun.com On Thu, Dec 24, 2009 at 9:29 PM, Pradeep Chetal < Pradeep.Chetal@xxxxxxxxxxxxxx> wrote: > > > Thomas, > > > > There are lot of updates (not inserts) but on some of the tables that are > populated by sequences and others without sequences. > > > > I will go through this and see if this helps. > > > > Thanks, > > > > -- Pradeep > > > ------------------------------ > > *From:* Thomas Roach [mailto:troach@xxxxxxxxx] > *Sent:* Thursday, December 24, 2009 9:08 AM > *To:* Pradeep Chetal > *Cc:* oracle-l@xxxxxxxxxxxxx > *Subject:* Re: Looking for pointers in troubleshooting -> RAC performance > degradation (single instance is fine) > > > > Sorry to early.. meant that it might "NOT" be the right solution for you :) > > On Thu, Dec 24, 2009 at 9:07 AM, Thomas Roach <troach@xxxxxxxxx> wrote: > > Hi, > > Are you doing a lot of inserts/updates to tables that have indexes that are > populated by sequences? You should find the objects the contention is on. To > assist with this, take a look at this page. > http://www.ardentperf.com/2007/09/12/gc-buffer-busy-waits-in-rac-finding-hot-blocks/ > > Basically what "could" be happening (what happened with me) was that I had > a bunch of sessions across nodes all fighting to put entries into the same > index blocks. Even on one node, this would be a contention issue. What I did > to fix my issue was identify the indexes with the contention and made them > reverse key indexes. With reverse key indexes you lose the ability to > perform certain operations like an index range scan. So if you do queries > where something is between this value and that value etc, it might be the > right solution for you. > > Good Luck. > > > > > On Thu, Dec 24, 2009 at 8:28 AM, Pradeep Chetal < > Pradeep.Chetal@xxxxxxxxxxxxxx> wrote: > > > > Folks, > > > > We have an app that is running well in single instance but when put on a > 2-node or 3-node RAC, we see pretty much similar performance. However, if > the CPU time is 55-60% in single instance, it becomes 20% in 3-node RAC and > top-5 itmed events become.. > > > > "gc buffer busy", "gc current block busy", "enq: TX- index contention > > > > Any help in what to look for will be greatly appreciated. > > > > Thanks, > > > > -- Pradeep > > *Pradeep Chetal* > Sr. Director - Infrastructure Architecture > ------------------------------ > > *Mformation Technologies Inc.* > *Switchboard:* +1 732 692 6200 > > > > Visit > > *WWW.MFORMATION.COM* and see how the MFORMATION SERVICE MANAGER can help > you to transform your business > > *Please consider the environment before printing* > > This message and the information contained herein is proprietary and > confidential and subject to the Mformation Confidentiality policy > statement, > you may request a copy by emailing info@xxxxxxxxxxxxxx > > > > -- > Thomas Roach > 813-404-6066 > troach@xxxxxxxxx > > > > > -- > Thomas Roach > 813-404-6066 > troach@xxxxxxxxx > > > Visit > *WWW.MFORMATION.COM* and see how the MFORMATION SERVICE MANAGER can help > you to transform your business > This message and the information contained herein is proprietary and > confidential and subject to the Mformation Confidentiality policy > statement, > > you may request a copy by emailing info@xxxxxxxxxxxxxx >