Author Archives: Bobby

I modified my query of DBA_HIST_SQLSTAT that I use for query tuning to include plan_hash_value.  This is nice because you can see whether a particular plan corresponds to a longer run time.  Here a link the the modified script(updated). Here … Continue reading →

I thought I had already posted on this, but I didn’t.  I recently used this hint to resolve an issue with a custom PeopleSoft Financials batch process running too long.  A particular query was taking over an hour instead of … Continue reading →

If all else fails and you can’t get the optimizer to join the tables together in an efficient order you can break the query into multiple queries saving the intermediate results in a global temporary table.  Here is how to … Continue reading →

Recently I discovered the RAC version of the AWR report – awrgrpt.sql.  Today was the first time I used it for a real system.  In this case a 12 node Exadata system.  awrgrpt.sql is in $ORACLE_HOME/rdbms/admin just like the normal … Continue reading →

I had a funny thing happen today.  I had recently participated in a forum thread about  library cache: mutex X waits.  In that discussion the library cache: mutex X waits were on an AWR report but when we dug deeper … Continue reading →

The list of the East Coast Oracle Users conference presentations came out: Click here for the list (NO LONGER EXISTS). My “Introduction to SQL Tuning” talk is on there.  I also submitted an Exadata talk but it looks like Michael … Continue reading →

I’ve changed the blog’s settings regarding comments.  I was trying to prevent spam but it looks like the settings I chose prevented people from leaving comments.  One person emailed me to ask about this.  So, I’m still going to moderate … Continue reading →

I can never remember where to put the (+) symbols in an Oracle SQL query to make it have an outer join.  I rarely need to write a query with an outer join and when I do I have to … Continue reading →

Download this zip of the example scripts and their logs. This post is to describe how I go about testing the performance affects of a change that has the potential to change the execution plans of many queries.  For example, … Continue reading →

I’ll be doing my Introduction to SQL Tuning talk at the East Coast Users Conference in October.  Come check it out! – Bobby