Parsing blocks stats blocks parsing

I had a five-minute conversation with Oracle development Friday that rocked my world.  I found out that parsing blocks stats which blocks parsing.

We have a system with queries that are taking minutes to parse.  These queries include the main tables on our database, one of which is interval partitioned and has 20,000 sub-partitions.  We have seen a situation where Oracle’s delivered statistics gathering job hangs on a library cache lock waiting (more...)

Alerting on plans that change for the worse

I’ve uploaded a monitoring script that I have worked on: zip.

The script alerts you when the optimizer runs a SQL statement with a potentially new and inefficient plan so you can intervene.  This script improves upon my earlier script which only alerts you to SQL statements running with new plans.  The new script compares the average elapsed time of the current plan with the average of the most often executed plan.  (more...)

Check out the new Oracle help web site

I found a broken link to an Oracle help document in one of my posts and when I went to the Oracle 12c database documentation to find the new URL to put in my post I found that Oracle had totally revamped their online manuals.

Here is a link to the new high level Oracle help site: url

I’ve only looked at it for a few minutes and can’t say whether I like it or (more...)

Oracle DBA job in Tempe, Arizona

We still have a position open on our Oracle database team here in Tempe, Arizona.  Here is the link with an updated job description: url

We have a great team and would love to have a new member to join us.

-Bobby

Useful Carlos Sierra post about queries changing performance

Saw an interesting post related to work I am doing locking in plans and finding plans that have changed: Carlos Sierra post on queries with changing performance.

Our DBA team uses versions of my sqlstat.sql script to find queries whose elapsed time change and we use a script from Carlos Sierra’s SQLT collection to force the execution plan back to an efficient plan that the optimizer choose in the past.  Carlos Sierra’s new (more...)

Script to count and recompile invalid objects

This is pretty simple, but I thought I would share it since it is helpful to me.  I have been preparing for a large migration which involves table, index, type, function, package, and procedure changes.  When I run a big migration like this I check for invalid objects before and after the migration and attempt to recompile any that are invalid.  By checking before and after the migration I know which objects (more...)

Recap of yesterday’s Arizona Oracle User Group (AZORA) meeting

Yesterday was the first meeting of the newly restarted Arizona Oracle User Group, AZORA.  It was a good first meeting to kick off what I hope will turn into an active club.

We met in the Tempe Public Library in a large downstairs room with a projector screen and plenty of seating with tables so it was easy to take notes.  We also had snacks.  I got a Paradise Bakery chocolate chip (more...)

Reminder: first Arizona Oracle User Group meeting tomorrow

Fellow Phoenicians (citizens of the Phoenix, Arizona area):

This is a reminder that tomorrow is the first meeting of the newly reborn (risen from the ashes) Arizona Oracle User Group.  Here are the meeting details: url

I hope to meet some of my fellow Phoenix area DBAs tomorrow afternoon.

– Bobby

 


Script to compare plan performance

Here’s a zip of a script I modified today: zip

Here’s an example output:

 QUERY_NUM SQL_ID        PLAN_HASH_VALUE EXECUTIONS AVG_ELAPSED OPTIMIZER_COST AVG_FETCHES  AVG_SORTS AVG_DISK_READS AVG_BUFFER_GETS   AVG_ROWS    AVG_CPU AVG_IOWAIT AVG_DIRECT_WRITES AVG_PHYS_READS AVG_PHYS_WRITES
---------- ------------- --------------- ---------- ----------- -------------- ----------- ---------- -------------- --------------- ---------- ---------- ---------- ----------------- -------------- ---------------
         1 gxk0cj3qxug85      2051250004   39504258  31630.2852             15  4.71993394 .444248288     4.07294381      440.124393 41.3960784 3447.83137 28056.5262                 0     .006406626               0
         1 gxk0cj3qxug85       548353012   24360619   (more...)

Tweaked bind variable script

I modified the bind variable extraction script that I normally use to make it more helpful to me.

Here was my earlier post with the old script: blog post

Here is my updated script:

set termout on 
set echo on
set linesize 32000
set pagesize 1000
set trimspool on

column NAME format a3
column VALUE_STRING format a17

spool bind2.log

select * from 
(select distinct
to_char(sb.LAST_CAPTURED,'YYYY-MM-DD HH24:MI:SS') 
  DATE_TIME,
sb.NAME,
sb.VALUE_STRING 
from 
DBA_HIST_SQLBIND  (more...)