The Oracle 11g parameter parallel_degree_limit is designed to put a cap on the maximum DOP for a statement.
The Oracle Data Base Reference 11g Release 2 (11.2) says this:
A numeric value for this parameter specifies the maximum degree of parallelism the optimizer can choose for a SQL statement when automatic degree of parallelism is active. Automatic degree of parallelism is only enabled if PARALLEL_DEGREE_POLICY is set to AUTO or LIMITED.
But that’s not (more...)
Last week I did a webinar on 12c Adaptive Optimization. The talk was recorded. The slides are here: 12c Adaptive Optimization V2 PDF. The recording can be found here: 12c Adaptive Optimization Recording. There were a number of follow up questions and emails so I thought I’d summarize here. Since (more...)
The APPEND_VALUES hint was introduced in 11.2 to allow direct path inserts with variables using the VALUES clause. i.e.
INSERT INTO XYZ (COL1, COL2) VALUES (:A, :B);
The feature was designed to allow bulk inserting via arrays of 100′s or 1000′s of records in a single insert statement. (more...)
Here’s a very quick note on a relatively recent addition to System Statistics. It’s the so called “Exadata mode”. This mode is intended to give the optimizer a little more info about the storage system on the Exadata platform. Here’s some info from an MOS note.
Oracle Sun Database Machine (more...)
I heard JP Dijcks speak at RMOUG in 2012 about a new parameter that would show up in 12c called parallel_degree_level. It’s basically a knob that you can turn to dial up (or down) the calculated DOP when setting parallel_degree_policy=auto. Early on (22.214.171.124) auto DOP seemed to (more...)
My favorite new Oracle Database 12c feature is the SQL Translation Framework. The feature grew out of SQL Developer’s ability to translate SQL from non-Oracle RDBMS’s. For example, there is a pre-built Sybase ASE translation package that is designed to translate the Sybase dialect of SQL into Oracle SQL dialect. (more...)