What Is a Domain Indexes in Oracle Database?
An extensible indexing framework lets a data-domain implementation supply custom search structures, operators, and maintenance routines.
How the Domain Indexes Algorithm Works
An extensible indexing framework lets a data-domain implementation supply custom search structures, operators, and maintenance routines.
When to Use Domain Indexes
Spatial, text, or custom types whose Oracle package provides a compatible indextype.
How to Create a Oracle Database Domain Indexes
Review data quality, existing structures, feature support, build time, and deployment requirements before creating an index on a production table.
CREATE INDEX places_geom_ix ON places (geometry) INDEXTYPE IS MDSYS.SPATIAL_INDEX;Domain Indexes Query Example
This example demonstrates the matching query shape. Check the execution plan to confirm that the engine can use the index.
SELECT place_id FROM places WHERE SDO_FILTER(geometry, :search_window) = 'TRUE';Queries Supported by Domain Indexes
Spatial, text, or custom types whose Oracle package provides a compatible indextype. A similar-looking predicate may not use the same access path; operators, expressions, key order, and data type all matter.
Read Performance, Storage, and Write Costs
Storage, DML, and tuning depend on the provider implementation and installed options. Indexes reduce some search work but require storage and add maintenance to writes.
Domain Indexes Limitations and Common Mistakes
Not a universal built-in tree; packages, options, licenses, operators, and versions matter.
Do not assume that an index being present means the optimizer chose it or that the query became selective.
How to Measure and Tune Domain Indexes
Follow the provider?s index maintenance guidance and verify operator binding and execution plans.
Compare representative plans and timings before and after, including concurrent writes and realistic data volumes.
Domain Indexes Questions
Will the database always use this index?
No. The optimizer weighs selectivity, estimated costs, statistics, cache state, and the amount of data returned.
What should I verify before production?
Confirm version support, query compatibility, write overhead, build/rollback procedures, and index behavior during backup and recovery.
Official Oracle Database Index Documentation
Check Oracle Database Concepts: Indexes and Index-Organized Tables for release-specific requirements and supported operators.