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Richard Foote

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Focusing Specifically On Oracle Indexes, Database Administration and Some Great Music
Updated: 5 hours 40 min ago

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

Index Compression Part VI: 12c Index Advanced Compression Block Dumps (Tumble and Twirl)

Thu, 2014-10-09 01:01
Sometimes, a few pictures (or in this case index block dumps) is better than a whole bunch of words :) In my previous post, I introduced the new Advanced Index Compression feature, whereby Oracle automatically determines how to best compress an index. I showed a simple example of an indexed column that had sections of index entries that were […]
Categories: DBA Blogs

Index Compression Part V: 12c Advanced Index Compression (Little Wonder)

Thu, 2014-10-02 04:28
I’ve finally managed to find some free time in the evening to write a new blog piece :) This will have to be the record for the longest time between parts in a series, having written Part IV of this Index Compression series way way back in February 2008 !! Here are the links to the previous articles […]
Categories: DBA Blogs

12.1.0.2 Introduction to Zone Maps Part I (Map Of The Problematique)

Wed, 2014-09-03 02:06
Zone Maps are new index-like structures 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 is simply a range of contiguous blocks within a table. Zone Maps are similar in concept to Exadata storage […]
Categories: DBA Blogs

12.1.0.2 Introduction to Attribute Clustering (The Division Bell)

Tue, 2014-08-26 00:03
One of the really cool new features introduced in 12.1.0.2 is Attribute Clustering. This new table based attribute allows you to very easily cluster data in close physical proximity based on the content of specific columns. As I’ve discussed many times, indexes love table data that is physically clustered in a similar manner to the index […]
Categories: DBA Blogs

12.1.0.2 Released With Cool Indexing Features (Short Memory)

Fri, 2014-07-25 00:18
Oracle Database 12.1.0.2 has finally been released and it has a number of really exciting goodies from an indexing perspective which include: Database In-Memory Option, which enables specific portions of the database to be in dual format, in both the existing row based format and additionally into an efficient memory only columnar based format. This in […]
Categories: DBA Blogs

Presenting at UKOUG Tech14 Conference (Ian Fish, U K Heir)

Tue, 2014-07-15 01:52
I’ve been lucky enough to present at various conferences, seminars and user group events over the years in some 20 odd countries. But somewhere I’ve never quite managed to present at before is the place of my birth, the UK. Well this year, I’ve decided end my drought and submitted a number of papers for the UKOUG Tech14 Conference and […]
Categories: DBA Blogs