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How to find SPM baseline by sql_id
When you start working with SQL Plan baselines, one of the annoying things that you might find is that the main “baseline” dictionary view dba_sql_plan_baselines does not have sql_id column. SQL>...
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Smile: I don’t always drink beer …
Remember the ever annoying (but hilarious) Dos Equis guy commercials about “the most interesting man in the world…” ? Well, I’ve heard a good one today: … I don’t always test my software … but when I...
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How to add a hint to ORACLE query without touching its text
If you’ve been a DBA long enough, you’ve probably seen multiple cases where certain SQL queries just refuse to cooperate. I.e. you KNOW that the query is supposed to use index IDX1, but ORACLE...
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How to find if your SQL is using SPM baseline
I’ve always wondered how many of my SQLs are NOT using baselines. Of course, when you run DBMS_XPLAN.DISPLAY_CURSOR for the statement, it can put a nicely formatted note for you, something like: Note...
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IOUG Collaborate 2012: The art of database sharding
Thanks everyone, who attended my presentation about database sharding at IOUG Collaborate. That was a lot of fun! Sharding is an awesome technique and I’ll blog separately on it, but for now see my...
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Scrap the SCP. How to copy data fast using pigz and nc
Have you ever heard that the speed of the system is determined by its slowest component ? I am made painfully aware of that every time I do data migrations. I.e. it doesn’t matter if you have 64 core...
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Read inconsistent queries in ORACLE database ? Sure, why not!
Read consistency is one of the coolest features of ORACLE database. In a nutshell, it means that your queries (at least, logically) do not pay attention to the outside world. I.e. your tables may be...
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RMOUG 2013 Training Days: SQL Top-N and Pagination pattern
I just returned from RMOUG 2013 training days in Denver, CO and I have to say that I’m impressed! This was an incredibly well organized and well run event with lots of great speakers and great...
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How to track SQL performance. Part 1: is it good to be “mean” ?
Let’s say that you have a very important SQL in your system. How do you know if it is performing well ? Is it running slow sometimes resulting in users having bad experience ? If so, when ? How many...
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How to track SQL Performance. Part 2: Percentiles!
In the previous article, we’ve seen that “average” SQL performance metrics that ORACLE provides out of the box can be useful, but only in a limited set of circumstances when underlying data...
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