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Concatenated Bitmap Indexes Part II (Everybody’s Got To Learn Sometime)
A basic little post to conclude this discussion. The issues regarding whether to go for single column indexes vs. concatenated indexes are similar for Bitmap indexes as they are for B-Tree indexes....
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Bitmap Index Degradation After DML Prior To 10g (Beauty and the Beast)
Bitmap Indexes have a bad reputation with regard to being problematic and suffering from severe degradation following heavy DML operations, especially larger amounts of insert activity. Bitmap indexes...
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Bitmap Index Degradation Since 10g (Fix You)
As discussed in my earlier post on Bitmap Index Degradation After DML Prior To 10g, Oracle wasn’t particularly efficient in the manner it maintained Bitmap Indexes after DML operations. During insert...
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Oracle11g Bitmap-Join IOTs (Us and Them)
With each new database release, nice little improvements and enhanced options continually get added. Since 11g R1, two index related features can finally be used in combination with each other. To...
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Bitmap Indexes and Not Equal (Holy Holy)
Way back, I previously discussed how the CBO will simply ignore any possible indexes when determining the best execution plan involving a NOT EQUAL(<>) condition, even if an index might in theory...
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Bitmap Indexes and Not Equal Part II (Sheep)
An excellent comment/question by mdinh made me realise my demos in Part I might be a little extreme in returning 0 rows and perhaps give the false impression that Not Equal conditions are only...
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Bitmap Indexes & Minimize Records_Per_Block (Little Wonder)
As mentioned in my first post regarding the use of Bitmap Indexes to service Not Equal predicates, an index entry in a Bitmap Index consists of the indexed value and a pair of rowids that determine the...
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Indexing Foreign Key Constraints With Bitmap Indexes (Locked Out)
Franck Pachot made a very valid comment in my previous entry on Indexing Foreign Keys (FK) that the use of a Bitmap Index on the FK columns does not avoid the table locks associated with deleting rows...
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Index Advanced Compression vs. Bitmap Indexes (Candidate)
A good question from Robert Thorneycroft I thought warranted its own post. He asked: “I have a question regarding bitmapped indexes verses index compression. In your previous blog titled ‘So What Is A...
View ArticleData Warehouse Design: To Index, or Not to Index, that is the question
This post is part of a series that discusses some common issues in data warehouses.When you query a star schema, you essentially have two choices; bitmap index and star transformation full scan, bloom...
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