Options for Tracing Oracle dbms_stats
A Baffling Case of ORA-00942Recently we had a good reason to find out what was going on behind the scenes with dbms_stats.The automatic stats collection job in a client’s database was frequently...
View ArticleWhen RMAN Validate Creates New Files
While doing some testing I found something happening with RMAN that was unexpected.After making an RMAN backup, I would run the VALIDATE RECOVERY FILES command.When it completed I found there were...
View ArticleRoom for Improvement – Using DBMS_REDEFINITION with Spatial Data
Resizing a Column in a Table With a Spatial ColumnRecently a client asked for help with using DBMS_REDEFINITION to modify a column in a table.As the intent was to reduce the precision of a numeric...
View ArticleAlter Session Kill on Steroids
Perhaps you have encountered something like this: A session that is consuming too many resources needs to be killed. You locate the session and use ALTER SYSTEM KILL SESSION ‘SID,SERIAL#’ to kill the...
View ArticleTracking ASM Metrics
Collecting ASM IO MetricsIf you are an Oracle DBA, then it is quite likely that Oracle ASM is used as the storage management for at least some of the databases you manage.Eventually you will want to...
View ArticleGit for Beginners
git, simplifiedPerhaps you’ve come across a great cache of publicly available SQL scripts that would be very useful in monitoring your databases, and these scripts are hosted on github. Getting those...
View ArticleSimplify Oracle Tracing with Creative Scripting
Running a SQL trace is something that all DBAs do to varying degrees. Let’s say you are working on optimizing a SQL statement, and experimenting with some different hints for indexes and optimizer...
View ArticlePatching Fun: GI and Database Patches
So, it has been some time since I have patched a database. Patching seemed necessary in a 12c database used for testing, as it was having some crashing issues. As the database and GI home were both...
View ArticleRMAN Full Backup vs. Level 0 Incremental
Perhaps you’ve wondered about this. What is the difference between taking an RMAN full backup and a level 0 incremental backup?If you read the documentation the following explanation will be found...
View ArticleOracle ASM Rebalance – Turn it up. To 11?
If you’ve ever seen or heard of the movie This is Spinal Tap then you have likely heard the phrase Turn it up to 11.Why bring this up?When ASM was introduced as a method for configuring storage for...
View ArticleHow to Decipher Oracle Internal Datatype Storage
What started out as an investigation into how the optimizer deals with predicates that are outside the known range of value became something else when I tried to determine just what Oracle believes low...
View ArticleExpert Insights: Oracle NET Troubleshooting for DBAs
Troubleshooting connection issues with Oracle SQL*Net can be difficult at times due to the many options that can be taken during configuration. One of the options is where the file tnsnames.ora may be...
View ArticleMore Fun With Oracle Timestamp Math
Timestamp MathSeveral years ago I wrote an article on Oracle date math. Amazingly, that article was still available online at the time of this writing.Working With Oracle DatesAn update to that article...
View ArticleOptimizer Stew – Parsing the Ingredients to Control Execution Plans
No matter how many times I have worked with Outlines, Baselines and Profiles, I keep having to look up reminders as to the differences between these three.There is seemingly no end to articles to the...
View ArticleNo Arguments Here – Use xargs for File Management Performance
Database Administrators and System Administrators have this in common: managing a large number of log files is just part of the job on Linux systems.Tools such as logrotate significantly simplify the...
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Improve Parsing and Query Performance – Fix Oracle’s Fixed Object Statistics
What do I mean by ‘fix’ the the fixed object statistics? Simply gather statistics to help the optimizer.What are ‘fixed objects’? Fixed objects are the x$ tables and associated indexes that data...
View ArticleAnalyze Index Validate Structure – The Dark Side
Recently a co-worker wanted to discuss a problem he had encountered after upgrading a database.The upgrade plan included steps to verify object integrity; this was being done with analyze table...
View ArticleTracefile Automation – Simplify Your Troubleshooting Tasks
Here’s a common Oracle troubleshooting scenario when a SQL statement needs tuning and/or troubleshooting:log on to dev serverconnect to database (on a different server)run the SQL statement with 10046...
View ArticleWhat’s Eating My Database? Where to Focus Performance Efforts Using Oracle AWR
No doubt you have at times been on the DBA side of this conversation, or one much like it.Help Desk: We have reports that the database is slowDBA: Really? OK, tell me when it was slow and I will...
View ArticleDirtyC0w – is that a beverage? Ensuring the Security of Your Linux Servers
If you’ve heard of a Black Cow, you may think that Dirty C0w is a variation on that drink.In reality, Dirty C0w is a privilege escalation vulnerability that is present in the Linux kernel.While the...
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