ALTER ASYNC MATERIALIZED VIEW

Description

This statement is used to modify asynchronous materialized views.

syntax

ALTER MATERIALIZED VIEW mvName=multipartIdentifier ((RENAME newName=identifier)
       | (REFRESH (refreshMethod | refreshTrigger | refreshMethod refreshTrigger))
       | REPLACE WITH MATERIALIZED VIEW newName=identifier propertyClause?
       | (SET  LEFT_PAREN fileProperties=propertyItemList RIGHT_PAREN))

illustrate

RENAME

Used to change the name of the materialized view

For example, changing the name of mv1 to mv2

ALTER MATERIALIZED VIEW mv1 rename mv2;

refreshMethod

Same as creating asynchronous materialized views

You cannot change a regular asynchronous materialized view to INCREMENTAL with ALTER MATERIALIZED VIEW, nor change an IVM to another default refresh method. To switch, recreate the materialized view.

refreshTrigger

Same as creating asynchronous materialized views

SET

Modify properties unique to materialized views

For example, modifying the grace_period of mv1 to 3000ms

ALTER MATERIALIZED VIEW mv1 set("grace_period"="3000");

Among the IVM properties, ivm_use_full_keys can only be set at creation time and cannot be modified. ivm_partition_window_limit can be modified; widening the window or removing the limit invalidates the baseline of the materialized view, and the next refresh rebuilds the whole materialized view. See Incremental View Maintenance (IVM).

REPLACE

ALTER MATERIALIZED VIEW [db.]mv1 REPLACE WITH MATERIALIZED VIEW mv2
[PROPERTIES('swap' = 'true')];

Replacing atoms with two materialized views

swap default is TRUE

• If the swap parameter is set to TRUE, it is equivalent to renaming the materialized view mv1 to mv2, and renaming mv2 to mv1 at the same time
• If the swap parameter is set to FALSE, it is equivalent to renaming mv2 to mv1 and deleting the original mv1

For example, if you want to swap the names of mv1 and mv2

ALTER MATERIALIZED VIEW db1.mv1 REPLACE WITH MATERIALIZED VIEW mv2;

For example, if you want to rename mv2 to mv1 and delete the original mv1

ALTER MATERIALIZED VIEW db1.mv1 REPLACE WITH MATERIALIZED VIEW mv2
PROPERTIES('swap' = 'false');

Keywords

ALTER, ASYNC, MATERIALIZED, VIEW