Clik here to view.
Tuning ‘log file sync’ wait events
In this blog entry, we will discuss strategies and techniques to resolve ‘log file sync’ waits. This entry is intended to show an approach based upon scientific principes, not necessarily a step by...
View ArticleClik here to view.
Import performance: Does import of date column resorts to single row inserts,...
We had a discussion about import performance in this otn forum . During the discussion, OP raised a doubt that import will resort to single row inserts for tables with date columns. Buffer parameter...
View ArticleClik here to view.
Performance issue: High Kernel mode CPU usage
Recently, we resolved a performance issue with one of our esteemed clients. Problem was interesting and worth blogging about it. Problem An application makes 300 static connections to database DB1 in...
View ArticleClik here to view.
Log file synch tuning #2
After reading my earlier blog about log file sync tuning a reader sent an interesting issue, worth blogging about it. Problem Excessive wait time for ‘log file sync’ event while wait time for ‘log...
View ArticleClik here to view.
Cardinality feedback to resolve a Cache buffers chains latch contention issue
Earlier, I blogged about resolving cache buffers chains latch contention in my earlier entry , in which, root cause was excessive index access due to Nested Loops join. Recently, we resolved another...
View ArticleClik here to view.
Lock table followed by DDL?
My client DBA wrote a small script: To drop a column to a busy table. This application is mostly an OLTP application and table is modified heavily. It is hard to get a lock on the table, even though...
View ArticleClik here to view.
DOUG presentation: Why does optimizer hate my SQL?
I presented about Cost based optimizer explaining why some times CBO chose inefficient access plan, even though, there is an efficient plan in the search space. This entry is to post presentation...
View ArticleClik here to view.
Library cache lock and library cache pin waits
I encountered few customer issues centered around library cache lock and library cache pin waits. Library cache lock and pin waits can hang instance, and in few cases, whole clusters of RAC instances...
View ArticleClik here to view.
RAC object remastering ( Dynamic remastering )
In RAC, every data block is mastered by an instance. Mastering a block simply means that master instance keeps track of the state of the block until the next reconfiguration event (due to instance...
View ArticleClik here to view.
RMOUG 2012 – Hello Denver!
On February 14-16, I’ll be at the Colorado Convention Center in Denver, Colorado for RMOUG’s Training Days Conference. This is the largest regional Oracle User Conference in North America and attracts...
View ArticleClik here to view.
Book: Expert Oracle RAC 12c
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...
View Article