Author: Bobby
Subscribing to Oak Table blogs feed
I’ve seen some very good information posted in this feed which combines blog postings from many different Oracle performance experts who are part of what is called the “Oak Table” http://www.oaktable.net/feed/blog-rss.xml I’ve b…
inode lock contention
In my forum discussion about free buffer waits I came across a term that I didn’t understand: “inode lock contention”. I’m pretty sure I had seen this same term years ago on one of Steve Adams’ pages on IO. But, I didn…
Interesting post on clustering factor
I just read this post about a new patch that will allow you to affect the way the optimizer calculates clustering factor and hence how likely it is to choose a particular index for a query plan. http://richardfoote.wordpress.com/2013/05/08/important-cl…
Oracle internals web site
This is a good web site with Oracle internals information: http://www.ixora.com.au/notes/ I’ve benefited from this one for years. – Bobby
Direct IO and db_writer_processes=36 on HP-UX reduced free buffer waits
In my previous post I explained that setting db_writer_processes=1, dbwr_io_slaves=32 made a 2-3 times reduction in run time of my test of 15 concurrent updates. Further testing has shown that an even greater improvement – really 10 times –…
Direct IO and db_writer_processes=36 on HP-UX reduced free buffer waits
In my previous post I explained that setting db_writer_processes=1, dbwr_io_slaves=32 made a 2-3 times reduction in run time of my test of 15 concurrent updates. Further testing has shown that an even greater improvement – really 10 times –…
Direct IO and db_writer_processes=36 on HP-UX reduced free buffer waits
In my previous post I explained that setting db_writer_processes=1, dbwr_io_slaves=32 made a 2-3 times reduction in run time of my test of 15 concurrent updates. Further testing has shown that an even greater improvement – really 10 times –…
db_writer_processes, dbwr_io_slaves with no asynch I/O on HP-UX
I’m working on an HP-UX system that doesn’t have asynchronous I/O configured and I’m getting a bunch of “free buffer waits” which indicates that the DBWR processes are having trouble writing updated blocks from memory to d…
DBA_HIST_SEG_STAT example
I used this query to debug some updating issues on a table: select ss.DATAOBJ#, sn.END_INTERVAL_TIME, ss.DB_BLOCK_CHANGES_DELTA, ss.PHYSICAL_WRITES_DELTA from DBA_HIST_SEG_STAT ss, DBA_HIST_SNAPSHOT sn, DBA_HIST_SEG_STAT_OBJ so where so.OWNER=’MYUSER’ …
DBA_HIST_ACTIVE_SESS_HISTORY shows PeopleSoft OPRIDs
You can use DBA_HIST_ACTIVE_SESS_HISTORY to show details about the PeopleSoft operator id (OPRID) and which part of the online application they were in. I was just looking at a Query Manager issue and found that DBA_HIST_ACTIVE_SESS_HISTORY populated…
