Index Dynamics – Part 3

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See previous post Index Dynamics - Part II or first part Index Dynamics - Part I

On this part, I’m going to share with you the final results for my 2 week experiment with indexes on their habitat, a production environment.

I’ve to forewarn that some data was not available, as the ANALYZE method fails for objects currently locked, given that our environment is a “live” production database and for consistency we scheduled all tests for a given time, which some days collided with business process. The Used Space graph shows those NA data points; (more...)

Index Dynamics – Part 2 (Halloween on the Block)

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View starting post: Index Dynamics - Part 1

As I've promised, today will share with you mid-term results for my index observations.

First we may see a graph of Used Space, as reported by column PCT_USED of table INDEX_STATS (right after an ANALYZE over each index). This percentage accounts the space allocated to the B-Tree that is used.

There is one line for every index we are considering, and note the legend on the graph showing the index name and the number of columns inside parenthesis.

What can be observed in this chart?
1) After (more...)

How to Flush your database caches

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Flushing the SGA memory areas, Shared Pool and Buffer Cache, it's an uncommon task, however, it gets useful when you're doing some tests and want to override the memory and go direct to disk, or when you have shared pool issues (here is a workaround, however I encourage you to find the root cause).

Shared Pool flush
This is the only sentence you have to know for releases 9i and up...
alter system flush shared_pool

Buffer Cache flush
For Oracle 9i I didn't know how to do this, fortunately found it today on Rahat Agivetova's (more...)

Index dynamics

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Today I will start with a series of 3 posts depicting the follow up of 4 index behavior on a Production database.

The purpose of this exercise is try to unveil the morphology these four indexes take during a given period of time, under what kind of load, model it in a graphical way. Since indexes are quite a black box, this exercises also proposes a complementary procedure for index quality measure.

Experiment subjects were selected using information on DBA_SEGMENTS+DBA_HIST_SEGMENTS, with focus on size and activity, indexes were choosen within the 400Mb-500Mb range thinking on (more...)

Interview with a Pro: Dan Norris

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Today I will share with you a video interview, this section will be entitled: "Interview with a Pro", and it's aimed to all of you, IT professionals or not related to IT at all. We will present remarkable people, with notable activism for Oracle & IT, and high expertise level on their field.

This time, I'm glad to feature our interview with Dan Norris, he is a consultant (ESA Practice Manager actually) with Piocon, President of the Oracle RAC SIG, member of the Independent Oracle Users Group (IOUG) and a notable member (more...)