ALTER MATERIALIZED VIEW

Changes materialized view table properties. The statement returns no results.

Limitations

Changing columns is not supported.
Change log, CDC, is not available for materialized views.

Synopsis

ALTER MATERIALIZED VIEW [<keyspace_name>.]<view_name>
  WITH <table_options> [ AND <table_options> ... ] ;

Legend
Syntax conventions	Description
UPPERCASE	Literal keyword.
Lowercase	Not literal.
`< >`	Variable value. Replace with a user-defined value.
`[]`	Optional. Square brackets (`[]`) surround optional command arguments. Do not type the square brackets.
`( )`	Group. Parentheses ( `( )` ) identify a group to choose from. Do not type the parentheses.
`\|`	Or. A vertical bar (`\|`) separates alternative elements. Type any one of the elements. Do not type the vertical bar.
`...`	Repeatable. An ellipsis ( `...` ) indicates that you can repeat the syntax element as often as required.
`'<Literal string>'`	Single quotation (`'`) marks must surround literal strings in CQL statements. Use single quotation marks to preserve upper case.
`{ <key> : <value> }`	Map collection. Braces (`{ }`) enclose map collections or key value pairs. A colon separates the key and the value.
`<datatype2`	Set, list, map, or tuple. Angle brackets ( `< >` ) enclose data types in a set, list, map, or tuple. Separate the data types with a comma.
`<cql_statement>;`	End CQL statement. A semicolon (`;`) terminates all CQL statements.
`[--]`	Separate the command line options from the command arguments with two hyphens ( `--` ). This syntax is useful when arguments might be mistaken for command line options.
`' <<schema\> ... </schema\>> '`	Search CQL only: Single quotation marks (`'`) surround an entire XML schema declaration.
`@<xml_entity>='<xml_entity_type>'`	Search CQL only: Identify the entity and literal value to overwrite the XML element in the schema and solrConfig files.

keyspace_name

Selects a keyspace.

view_name

Selects the materialized view.

table_options

Table options are defined when the materialized view is created. Modify the table_options in the WITH clause using the following syntax:

String values wrapped in single quotes: <option_name> = '<value>'
Non-string values (not quoted): <option_name> = <value>
Options with multiple subproperties in simple JSON format: <option_name> = { <option_map> }
Set multiple table options using AND.

Materialized views do not perform repair in the same way as the base table, so properties regarding repair are invalid.

Examples

Alter bloom filter and add a metadata comment

Add a comment and set the bloom filter properties:

ALTER MATERIALIZED VIEW cycling.cyclist_by_age
  WITH comment = 'A most excellent and useful view'
  AND bloom_filter_fp_chance = 0.02;

Alter compression and compaction

Use a property map to specify new properties for compression or compaction.

ALTER MATERIALIZED VIEW cycling.cyclist_by_age
  WITH compression = {
    'sstable_compression' : 'DeflateCompressor',
    'chunk_length_kb' : 64
  }
  AND compaction = {
    'class' : 'SizeTieredCompactionStrategy',
    'max_threshold' : 64
  };

Alter caching

You can create and change caching properties in the materialized view definition.

This example enables the row cache:

ALTER MATERIALIZED VIEW cycling.cyclist_by_age
WITH caching = {
  'rows_per_partition' : '15'
};

Caching is also configured in cassandra.yaml.

Get materialized view definition

Use DESCRIBE MATERIALIZED VIEW to get the current properties for a materialized view:

DESCRIBE MATERIALIZED VIEW cycling.cyclist_by_age;

Result

CREATE MATERIALIZED VIEW cycling.cyclist_by_age AS
    SELECT age, cid, birthday, country, name
    FROM cycling.cyclist_base
    WHERE age IS NOT NULL AND cid IS NOT NULL
    PRIMARY KEY (age, cid)
    WITH CLUSTERING ORDER BY (cid ASC)
    AND additional_write_policy = '99PERCENTILE'
    AND bloom_filter_fp_chance = 0.01
    AND caching = {'keys': 'ALL', 'rows_per_partition': '100'}
    AND comment = 'Based on table cyclist_base'
    AND compaction = {'class': 'org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy', 'max_threshold': '32', 'min_threshold': '4'}
    AND compression = {'chunk_length_in_kb': '64', 'class': 'org.apache.cassandra.io.compress.LZ4Compressor'}
    AND crc_check_chance = 1.0
    AND default_time_to_live = 0
    AND gc_grace_seconds = 864000
    AND max_index_interval = 2048
    AND memtable_flush_period_in_ms = 0
    AND min_index_interval = 128
    AND read_repair = 'BLOCKING'
    AND speculative_retry = '99PERCENTILE';

ALTER MATERIALIZED VIEW

Limitations

Synopsis

Examples

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