Jul 08

OCM 11g Preparation – Use partitioned indexes

I’ve already talked about this topic here and here. Basically we have 2 types of partitioned indexes: GLOBAL and LOCAL: Local Partitioned Indexes. Local indexes can only be unique if the partitioning key is a part of the index key. A bitmap index on a partitioned table must be a local index. Global Partitioned Indexes. Note here …

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Jul 08

OCM 11g Preparation – Use multi column statistics

Multi column is another item any DBA must know about. It’s very important on tables where you have 2 columns that are correlated. So you must tell the optimizer that! The classical example for that is: How many people have a birth month of May? How many people have a Zodiac sign of Taurus? How …

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Jul 08

OCM 11g Preparation – Gather statistics on a specific table without invalidating cursors

Interesting this topic, because It’s very very specific. So, the best thing is know how to do that because the chance of having it in the exam is 100%. “When statistics are updated for a database object, Oracle Database invalidates any currently parsed SQL statements that access the object. The next time such a statement executes, the …

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Jul 08

OCM 11g Preparation – Use Result Cache

Result Cache is not enabled by default but is a such amazing feature that can make your 3 hours query run in less than 1 second after the first call. However, your result set need to be short and the tables involved might not be modified so often. The Oracle official documentation for Result Caches is short. So read …

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Jul 06

OCM 11g Preparation – Administer flashback data archive and schema evolution

I’ve already talked about that in the topic Perform various recovery operations using Flashback technology but this is here again. For Oracle to have created a separate topic for that, this probably means you should not even think in skipping to study that. Be well prepared. Practice: Creating a Flashback Data Archive Enabling and Disabling Flashback Data …

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