1. Database Reference
  2. Initialization Parameters
  3. Initialization Parameters
  4. APPROX_FOR_COUNT_DISTINCT

2.14 APPROX_FOR_COUNT_DISTINCT

APPROX_FOR_COUNT_DISTINCT automatically replaces COUNT (DISTINCT expr) queries with APPROX_COUNT_DISTINCT queries.

Property Description

Parameter type

Boolean

Default value

false

Modifiable

ALTER SESSION, ALTER SYSTEM

Modifiable in a PDB

Yes

Range of values

true | false

Basic

No

Oracle RAC

Different instances can use different values.

Query results for APPROX_COUNT_DISTINCT queries are returned faster than the equivalent COUNT (DISTINCT expr) queries. APPROX_COUNT_DISTINCT queries are useful for situations where a tolerable amount of error is acceptable in order to obtain faster query results than with a COUNT (DISTINCT expr) query.

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