ALTER MATERIALIZED VIEW

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

Restriction: Cassandra does not support changing the name or columns of the materialized view.

Synopsis

ALTER MATERIALIZED VIEW [keyspace_name.] view_name 
[WITH table_options]

Table 1. Legend
Syntax conventions	Description
UPPERCASE	Literal keyword.
Lowercase	Not literal.
`Italics`	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.
`<datatype1,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

To alter a materialized view in a keyspace other than the current keyspace, put the keyspace name in front of the name of the materialized view, followed by a period.

view_name

The name of the new materialized view.

table_options

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

Single value:
```
option_name = 'string_value'
```
Enclose string values in single quotes.

Specify options with multiple subproperties in simple JSON format:

option_name = { 
   'subproperty_name' : 'value', 
   'subproperty_name' : 'value',
   'subproperty_name' : 'value' [, ...] }

Separate multiple options with AND:

ALTER MATERIALIZED VIEW keyspace_name.table_name 
WITH option_name = 'string_value'
AND option_name = { 
   'subproperty_name' : 'string_value', 
   'subproperty_name' : numeric_value[, ...] };

Examples

Modifying table properties

For an overview of properties that apply to materialized views, see table_options.

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

Modifying 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};

Changing caching

You can create and change caching properties using a property map.

This example changes the keys property to NONE (the default is ALL) and changes the rows_per_partition property to 15.

ALTER MATERIALIZED VIEW cycling.cyclist_by_age 
WITH caching = { 
   'keys' : 'NONE', 
   'rows_per_partition' : '15' };

Viewing current materialized view properties

Use DESCRIBE MATERIALIZED VIEW to see all current properties.

DESCRIBE MATERIALIZED VIEW cycling.cyclist_by_age

CREATE MATERIALIZED VIEW cycling.cyclist_by_age AS
    SELECT age, cid, birthday, country, name
    FROM cycling.cyclist_mv
    WHERE age IS NOT NULL AND cid IS NOT NULL
    PRIMARY KEY (age, cid)
    WITH CLUSTERING ORDER BY (cid ASC)
    AND bloom_filter_fp_chance = 0.02
    AND caching = {'keys': 'ALL', 'rows_per_partition': 'NONE'}
    AND comment = 'A most excellent and useful view'
    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.DeflateCompressor'}
    AND crc_check_chance = 1.0
    AND dclocal_read_repair_chance = 0.1
    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_chance = 0.0
    AND speculative_retry = '99PERCENTILE';