ALTER KEYSPACE

Changes keyspace replication strategy and enables or disables commit log.

Modifies the keyspace replication strategy, which is the number of copies of the data in each datacenter, , and/or disable the commit log for writes, Durable Writes.

Note: Datacenter names are case-sensitive. Verify the case of the using utility, such as dsetool status.

Restriction: Changing the keyspace name is not supported.

Synopsis

ALTER KEYSPACE keyspace_name 
  WITH REPLICATION = { replication_map }
  [ AND DURABLE_WRITES = ( true | false ) ] ;

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.

replication_map

'class' : 'SimpleStrategy', 'replication_factor' : N

Assigns the same replication factor to the entire cluster. Use for evaluation and single datacenter test and development environments only.

REPLICATION = { 
 'class' : 'SimpleStrategy', 
 'replication_factor' : N 
}

'class' : 'NetworkTopologyStrategy', 'datacenter_name' : N, ...

After the class declaration, assign replication factors to each datacenter by name in a comma-separated list. Use in production environments and multi-DC test and development environments. Datacenter names must match the snitch DC name; see Snitches.

REPLICATION = { 
 'class' : 'NetworkTopologyStrategy', 
 'datacenter_name' : N [, 
 'datacenter_name' : N ] 
 }

Important: Use only replication strategy implementations bundled with DSE.

DURABLE_WRITES = true | false

Optional. (Not recommended), false bypasses the commit log when writing to the keyspace. Default value is true.

CAUTION: Never disable durable writes when using SimpleStrategy replication.

Example

Change the cycling keyspace to NetworkTopologyStrategy in a single datacenter and turn off durable writes (not recommended). This example uses the default datacenter name with a replication factor of 1.

ALTER KEYSPACE cycling
WITH REPLICATION = { 
  'class' : 'NetworkTopologyStrategy',
  'SearchAnalytics' : 1
} 
AND DURABLE_WRITES = false;