Monthly archives for December, 2011

Ad: The Oracle Query Optimizer 2-Day Seminar

Dec18
2011 Leave a Comment Written by Christian Antognini

The 31st of January and 1st of February 2012 I will present a 2-day seminar about the Oracle query optimizer in Ballerup (DK). The event is organized by Miracle A/S. The content, which is based on the chapters 2, 4, 5, 6, 9 and 10 of my book, is the following:

  • Chapter 1 describes the life cycle of SQL statements and when the database engine can share cursors.
  • Chapter 2 describes the aim and architecture of the query optimizer.
  • Chapter 3 and 4 discuss the statistics used by the query optimizer to carry out its work.
  • Chapter 5 describes the initialization parameters influencing the behavior of the query optimizer and how to set them.
  • Chapter 6 outlines different methods of obtaining execution plans, as well as how to read them and recognize inefficient ones.
  • Chapter 7 describes how to take advantage of available access structures in order to access data stored in a single table efficiently.
  • Chapter 8 goes beyond accessing a single table, by describing how to join data from several tables together.

The flyer and this page provide detailed information about the seminar.

Posted in Query Optimizer, Speaking, TOP

Challenges and Chances of the 11g Query Optimizer

Dec12
2011 2 Comments Written by Christian Antognini

Challenges and Chances of the 11g Query Optimizer is the name of a presentation I gave at several events (e.g. Trivadis Performance Days, Oracle OpenWorld, DOAG Konferenz, UKOUG Conference) throughout 2011. Its abstract is the following:

With every new release, the query optimizer is enhanced. Oracle Database 11g Release 1 and Release 2 are no exception to the rule. Specifically, they introduce key improvements in the following areas: indexing, optimization techniques, object statistics and plan stability. The aim of this presentation is to review the new features from a practical point of view as well as to point out challenges related to them. In other words, to let you know what you can expect from the query optimizer when you upgrade to Oracle Database 11g.

The aim of this short post is to point out that I made available the current version of the slides and all the scripts that go with them here.

The structure of the presentation (incl. a reference to the available scripts) is the following:

  • Observations
    • Number of Query Optimizer Parameters by Release
    • Number of Query Optimizer Bugs Fixed by Patchset
  • Indexing
    • Invisible Indexes (ex_invisible_index.sql)
    • Index Support for Linguistic LIKE (ex_linguistic_like.sql)
    • INDEX REBUILD and Statistics History (ex_index_rebuild.sql)
  • Optimization Techniques
    • Full Outer Join (ex_full_outer_join.sql)
    • Join-Filter Pruning (ex_join_filter_pruning.sql)
    • Table Expansion (ex_table_expansion.sql)
    • Join Factorization (ex_join_factorization.sql)
    • OR Expansion (ex_or_expansion.sql)
    • Join Elimination (ex_join_elimination.sql)
    • Subquery Unnesting (ex_subquery_unnesting.sql)
  • System and Object Statistics (DBMS_STATS)
    • Workload System Statistics
    • Object Statistics – Default Preferences
    • Object Statistics – Auto Sample Size
    • Object Statistics – Pending Statistics (ex_pending_object_statistics.sql)
    • Object Statistics – Incremental Statistics (ex_incremental_stats.sql)
    • Object Statistics – Extended Statistics on Expressions (ex_extended_statistics1.sql)
    • Object Statistics – Extended Statistics on Column Groups (ex_extended_statistics2.sql)
    • Object Statistics – Seeding Column Groups
    • Object Statistics – Comparing Statistics (ex_comparing_statistics.sql)
    • Object Statistics – Locks not Exported
    • JOB_QUEUE_PROCESSES
  • Plan Stability
    • CURSOR_SHARING
    • SQL Plan Baselines (ex_execution_plan_stability.sql, ex_execution_plan_stability_10g.sql, ex_execution_plan_stability_11g.sql)
    • Stored Outlines
    • Adaptive Cursor Sharing (ex_bind_peeking.sql, ex_bind_peeking_bind_aware.sql)
    • Cardinality Feedback (ex_cardinality_feedback.sql)
Posted in 11gR1, 11gR2, Bug, Indexes, Object Statistics, Query Optimizer, Speaking, System Statistics

Ad: Trivadis TechEvent 2011

Dec01
2011 1 Comment Written by Christian Antognini

All Trivadis employees meet twice a year near Zurich for a unique conference called TechEvent.

The TechEvents, with up to 15 parallel sessions, are among the largest IT conferences in Switzerland. During two days, employees can attend sessions about a wide range of both technical and non-technical subjects.

Watch the following (German spoken) video to know more about it…

Posted in Trivadis