One of the options for cloning an environment with limited disk space  involves creating a parameters file for the RMAN clone memory script to run that contains the “skip tablespace” feature.  This allows the DBA to retain a working list of tablespaces that contain data that isn’t required in development/test or for other cloning purposes when performing the actual clone. startup auxiliary nomount; run { allocate auxiliary channel c1 device type disk; …so on and so forth for all the channels desired… duplicate target database to SKIP TABLESPACE USERS,TBL_DATA1,TBL_INDX1,….; } This can also be extremely helpful in environments where disk…

A common initial resolution to reporting requirements without a reporting database is to utilize materialized views.  Unfortunately, the cost to refresh these views can be extremely expensive on a database, especially if it’s an OLTP that rarely has a lull in activity. A lesser known feature of Oracle’s is the Change Data Capture, (a.k.a CDC http://download.oracle.com/docs/cd/B10500_01/server.920/a96520/cdc.htm ) The CDC process utilizes a materizalized view log on a source table with a destination copy of the source table that can be kept insync with the original in any interval chosen.  The result is often a much lighter footprint than an mview refresh,…

In my years as an Oracle and SQL Server DBA and the many technical environments I’ve worked in, there’s almost always one database in each place that is a hybrid of OLTP and OLAP.  A highly transactional database that also has reporting requirements, but no separate reporting database.  This type of database is pretty much a guaranteed challenge for any DBA.   On one hand, the DBA has demands of the application demanding micro-second response time for completion of transactions.  On the other, he or she has users wanting information about the data resulting from all those transactions.  A DBA’s best course for successfully taming these types of hybrid environments…

Sigh….IF I could only live in “Uncle Larry’s” perfect database world where I have more control over what choices are made from the conception of the database’s life and know exactly what goals a development group has vs. Oracle. How much easier a DBA’s life would be if we could just say, “Sorry, Oracle’s new feature would work well only if you completely redesign the logic of your process in code A, B and C of our main systems that have naturally grown in complexity over the years.  Of course, you don’t mind adjusting all priorities for the next six…

After upgrading to 10.2.0.5 on Linux, our Oracle Enterprise Manager would report intermittently that the OC4J was down- Target Name=EnterpriseManager0.serve3r Target type=Oracle Application Server Host=mtlincoln Occurred At=March 12, 2010 3:09:52 PM MDT Message=The application server instance is down Severity=Critical Acknowledged=No Notification Rule Name=Application Server Availability and Critical States Notification Rule Owner=SYSMAN If you immediately checked the status of the OEM, all responses reported acceptable- ./opmnctl status Processes in Instance: EnterpriseManager0.serv3r ——————-+——————–+———+——— ias-component                 | process-type              |pid | status ——————-+——————–+———+——— HTTP_Server                   | HTTP_Server           | 25823 | Alive LogLoader                        | logloaderd                |   N/A | Down dcm-daemon                     | dcm-daemon            |   N/A | Down OC4J                                | Home                      |   25822 | Alive…

I know I owe a few folks a blog on temp tablespace groups-  THANK YOU for your patience, I know these last couple months I’ve been way too busy and haven’t been able to allocate the time I would have liked here… Temp tablespace groups ROCK–  plain and simple..  This is a feature I have been working with extensively and have seen great performance improvement with in my datawarehouse environments when implemented correctly.  My main focus has been striping temp tablespace groups across fusion I/O cards, but the improvement moving from a standard temp tablespace to a temp tablespace group on standard hardware shows significant improvement…

Let’s say you have a database that everything can be recreated just by re-running a process and no nightly backups are required-  the database would be quicker to recreate from the backup running on it’s source database than restoring from a nightly backup or taking the performance hit of doing so.  Let’s say you have three tablespaces that are on I/O fusion cards that aren’t protected by hardware mirroring and losing these three could be more of a challenge than the business would like to have.  What options could you come up with to protect those tablespaces? Oracle Streams? CTAS…

Interesting Issue… I was working on an interrupted distributed, (remote) transaction that I’d come across in one of our smaller reporting systems and attempting to rerun since 2008 against a decommissioned database, (yes, I said 2008…) This is a very “sublime” issue, as Oracle thinks it’s just taking care of a problem behind the scenes, but, like I said, this database no longer existed and was taken down while this remote process was running. The problem consisted of three databases, the reporting database, we’ll call REPRT_1, the current production warehouse, PROD_1 and the older production base, PROD_X Oracle keeps submitting…

Tanel Poder had a great post about bind variable peeking, http://blog.tanelpoder.com/2010/02/02/bind-variable-peeking-execution-plan-inefficiency/  I run into this exact issue more often than I would like to and have found a few tricks to refrain it from happening in code that is “vulnerable” to the situation. Truthfully, there isn’t much you can do when Oracle has gone in and performed a bind peek and chosen a poor example to peek on.  As a DBA, you simply know there is an issue when the explain plan states that the CBO has determined the cost is exceptionally low to perform a nested loop on a…

The Lead Developer and I have been working very, very hard on tuning the main process that produces much of the revenue for our company. The tuning exercise has been very successful but we’ve run into some challenging on the pre-processing that occurs for each week to build the mart that the newly tuned process runs on afterwards. Due to this, I’ve been granted some time to monitor the build process a little closer than previously and although I have a lot of tuning to do, some of the largest challenges comes in the form of queries that the analysts…