Views #

A view is a logical table that encapsulates business logic and domain-specific semantics. While most compute engines support views natively, each engine stores view metadata in proprietary formats, creating interoperability challenges across different platforms. Paimon views abstracting engine-specific query dialects and establishing unified metadata standards. View metadata could enable centralized view management that facilitates cross-engine sharing and reduces maintenance complexity in heterogeneous computing environments.

Catalog support #

View metadata is persisted only when the catalog implementation supports it:

Hive metastore catalog – view metadata is stored together with table metadata inside the metastore warehouse.
REST catalog – view metadata is kept in the REST backend and exposed through the catalog API.

File-system catalogs do not currently support views because they lack persistent metadata storage.

Representation structure #

Field	Type	Description
`query`	`string`	Canonical SQL `SELECT` statement that defines the view.
`dialect`	`string`	SQL dialect identifier (for example, `spark` or `flink`).

Multiple representations can be stored for the same version so that different engines can access the view using their native dialect.

Operations #

Create or replace view #

Use CREATE VIEW or CREATE OR REPLACE VIEW to register a view. Paimon assigns a UUID, writes the first metadata file, and records version 1.

CREATE VIEW sales_view AS
SELECT region, SUM(amount) AS total_amount
FROM sales
GROUP BY region;

Alter view dialect via procedure #

Paimon provides the sys.alter_view_dialect procedure so that engines can manage multiple SQL representations for the same view version.

Flink example #

-- Add a Flink dialect
CALL [catalog.]sys.alter_view_dialect('view_identifier', 'add', 'flink', 'SELECT ...');

-- Update the stored Flink dialect
CALL [catalog.]sys.alter_view_dialect('view_identifier', 'update', 'flink', 'SELECT ...');

-- Drop the Flink dialect representation
CALL [catalog.]sys.alter_view_dialect('view_identifier', 'drop', 'flink');

Spark example #

-- Add a Spark dialect
CALL sys.alter_view_dialect('view_identifier', 'add', 'spark', 'SELECT ...');

-- Update the Spark dialect
CALL sys.alter_view_dialect('view_identifier', 'update', 'spark', 'SELECT ...');

-- Drop the Spark dialect
CALL sys.alter_view_dialect('view_identifier', 'drop', 'spark');

Drop view #

DROP VIEW view_name;