Why have you suggested that you have a problem with "gc buffer busy waits", then reported the time for "TX enqueues". 54 seconds doesn't sound an enormous amount in one hour for a system that needs to run on 4 node RAC - so we need to see the scale of the problem. How about giving us a representative sample from the Top 5 Timed Events. Regards Jonathan Lewis http://jonathanlewis.wordpress.com/all_postings Author: Oracle Core (Apress 2011) http://www.apress.com/9781430239543 ----- Original Message ----- From: "Krishna" <krishna.setwin@xxxxxxxxx> To: "Oracle List" <oracle-l@xxxxxxxxxxxxx> Sent: Monday, September 17, 2012 2:24 AM Subject: Question on gc buffer busy waits | Hi, | 11.2.0.3.0 | RAC - 4 node | | we are facing "gc buffer busy acquire waits" in our database | intermittently. This is an OLTP system. | we are getting lot of blocking on our system. for example: 54 seconds in DB | Time is spent waiting for TX lock | | we are updating same table from all services that are on all nodes..this is | our primary table.. | the primary key on the table is auto-generated. | | 1. I updated all stats | 2. re-indexed indexes.. | | Did anybody face the same problem??? | | will creating a reverse key index on primary solve our problem?? (table has | abt 2 million records) | | Thanks in advance.. -- //www.freelists.org/webpage/oracle-l