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Richard Foote

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Focusing Specifically On Oracle Indexes, Database Administration and Some Great Music
Updated: 6 hours 37 min ago

12.1.0.2 Introduction to Zone Maps Part III (Little By Little)

Mon, 2014-11-24 00:16
I’ve previously discussed the new Zone Map database feature and how they work in a similar manner to Exadata Storage indexes. Just like Storage Indexes (and conventional indexes for that manner), they work best when the data is well clustered in relation to the Zone Map or index. By having the data in the table […]
Categories: DBA Blogs

Index Advanced Compression vs. Bitmap Indexes (Candidate)

Thu, 2014-10-30 23:59
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 Good Cardinality Estimate For A Bitmap Index Column ? (Song 2)’ you came to the conclusion that ‘500,000 distinct values in a 1 […]
Categories: DBA Blogs

12.1.0.2 Introduction to Zone Maps Part II (Changes)

Thu, 2014-10-30 00:45
In Part I, I discussed how Zone Maps are new index like structures, similar to Exadata Storage Indexes, that enables the “pruning” of disk blocks during accesses of the table by storing the min and max values of selected columns for each “zone” of a table. A Zone being a range of contiguous (8M) blocks. I […]
Categories: DBA Blogs