OPTIMIZERINFORMATION

Definition

The system table OPTIMIZERINFORMATION contains the information about value distributions that is determined by the UPDATE STATISTICS statement and used by the SQL Optimizer.

Structure

OPTIMIZERINFORMATION

SCHEMANAME

CHAR(32)

Name of the schema of the table

TABLENAME

CHAR(32)

Name of the table

COLUMNNAME

CHAR(32)

Name of a single, non-indexed column

INDEXNAME

CHAR(32)

Name of the index

DISTINCTVALUECOUNT

FIXED(10)

Number of distinct values in column, index, or primary key

CALCULATEDSIZE

FIXED(10)

Memory requirements of (primary key) index calculated by last UPDATE STATISTICS (KB)

See also:

SQL Reference Manual, UPDATE STATISTICS Statement (update_statistics_statement), EXPLAIN Statement (explain_statement)

Concepts of the Database System, SQL Optimizer

Database Administration in CCMS, SQL Optimizer in CCMS, Scheduling Updates of the SQL Optimizer Statistics