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Bloom Filters
26 September 08 06:24 | Striving for Optimal Performance

Oracle Database, as of 10g Release 2, uses bloom filters in various situations. Unfortunately, no information about their usage is available in Oracle documentation. For this reason, I decided to write a paper to explain not only what bloom filters are...

Abgelegt unter: 11gR1, 10gR2, Query Optimizer

Long Parses
31 August 08 12:21 | Striving for Optimal Performance

From time to time I have to fight against long parses. In this post I would like to share with you what happened to a customer of mine while upgrading from 9.2.0.7 to 10.2.0.3 (10.2.0.4 was not yet available at that time). The parse of a complex SQL statement...

Abgelegt unter: 10gR2, Query Optimizer, 9iR2

SQL Profiles in the Data Dictionary
19 August 08 09:40 | Striving for Optimal Performance

In the paper SQL Profiles (page 22) I described the data dictionary tables where the hints belonging to SQL profiles are stored. For example, with the following query it is possible to display the hints associate to the SQL profile named opt_estimate...

Abgelegt unter: 11gR1, 10gR2, 10gR1, Query Optimizer

Operation CONNECT BY WITH FILTERING
17 Juni 08 11:09 | Striving for Optimal Performance

It happened to me several times to being asked about the mysterious full table scan in CONNECT BY operations. In this post I would like to share with you some of the information I wrote about it in my book (pages 233 to 236) . The operation CONNECT BY...

Abgelegt unter: TOP, Execution Plan, 11gR1, 10gR2, 10gR1