CREATE INDEX

Defines a new index for a single column of a table.

CQL supports creating an index on most columns, including the partition and cluster columns of a PRIMARY KEY, collections, and static columns. The one exception is that an index cannot be defined based on a single-column partition key.

All column date types except the following are supported for indexes:

  • counter

  • Geospatial types: PointType, LineStringType, PolygonType

  • Non-frozen user-defined type (UDT)

  • Frozen user-defined type (UDT)

For maps, you can create indexes using the key, value, or entry (a key:value pair). You can create multiple secondary indexes on the same database table, with each index based on any column in the table.

You can define an index on any single column in a table’s composite partition key (a partition key comprised of multiple columns). If you need to query based on one of those columns, an index is a helpful option. You can define an index on each column in a composite partition key, if needed.

Defining one or more indexes based on any column in a database table (with the rules noted above) subsequently enables performant queries that use the indexed column to filter results.

Syntax

CREATE [CUSTOM] INDEX [ IF NOT EXISTS ] [ <index_name> ]
  ON [<keyspace_name>.]<table_name>
  ([ KEYS | VALUES | ENTRIES | FULL] <column_name>)
    USING <index_type>
  [ WITH OPTIONS = { <option_map> } ] ;
Syntax legend
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.

Parameters

index_name

Optional identifier for index. If no name is specified, the default is <table_name>_<column_name>_idx. Enclose in quotes to use special characters or to preserve capitalization.

Index names are unique per keyspace because indexes are created at the keyspace level and not at the table level.

The index name must be a unique identifier for the index for each table within a keyspace. Enclose in quotes to use special characters or preserve capitalization. If you do not specify an index name, CQL generates one for you, with the pattern <table_name>_<column_name>_idx. This requirement is true for all indexes.

If you use IF NOT EXISTS in a CREATE [CUSTOM] INDEX command, the command fails silently if an index with the same name already exists in the keyspace. If you want the command to return an error when an index with the same name already exists, don’t use IF NOT EXISTS.

keyspace_name

Optional name of the keyspace that contains the table to index. If no name is specified, the current keyspace is used.

table_name

The name of the table on which the index is being defined.

column_name

The name of the column to index.

If used with a map, the column name is the map name. For maps, you can create indexes using the key, value, entry (a key:value pair), or full content of the collection.

SAI allows only alphanumeric characters and underscores in names. SAI returns InvalidRequestException if you try to define an index on a column name that contains other characters, and does not create the index.

map_name

Used with collections, identifier of the map_name specified in CREATE TABLE …​ map(<map_name>). The regular column syntax applies for collection types list and set.

CREATE INDEX | CREATE CUSTOM INDEX, USING <index_type>

See Index type options.

WITH OPTIONS = { <option_map> }

See SAI options .

Index type options

Option Description

SAI

A feature that is not available in all CQL distributions, but is recommended for production use in the distributions where it is available.

Define with USING StorageAttachedIndex. CREATE CUSTOM INDEX must be used to create an SAI index. If USING is not specified or SAI is not enabled, the default is 2i.

SAI options

The options are specific to the index type and are not required. The <option_map> is a map of options and their values defined in JSON simple format.

Option Description Default

similarity_function

Vector search relies on computing the similarity between vectors to identify relevant matches. The similarity function is used to compute the similarity between two vectors. Choices are EUCLIDEAN, DOT_PRODUCT, or COSINE.

COSINE

source_model

Configures the index for optimal performance for your vectors. Choices are: openai_v3_large, openai_v3_small, ada002, gecko, bert, other.

other

case_sensitive

Allows case-insensitive searches.

true

normalize

Allow searches to be normalized for Unicode characters. SAI supports Normalization Form C (NFC) Unicode. When set to true, SAI normalizes the different versions of a given Unicode character to a single version, retaining all the marks and symbols in the index. For example, SAI would change the character Å (U+212B) to Å (U+00C5).

When implementations keep strings in a normalized form, equivalent strings have a unique binary representation. See Unicode Standard Annex #15, Unicode Normalization Forms.

false

ascii

Allow searches to be limited to ASCII characters. When set to true, SAI converts alphabetic, numeric, and symbolic characters that are not in the Basic Latin Unicode block (the first 127 ASCII characters) to the ASCII equivalent, if one exists. For example, this option changes à to a.

false

index_analyzer

The class that implements the analyzer. Choices are STANDARD, SIMPLE.

STANDARD

tokenizer

The tokenizer for the index. Choices are standard, whitespace, ngram, keyword, simplepattern, stop, and mapping.

standard

filters

The filters for the index. Choices are: porterstem, lowercase, synonym, and languages, including stem definitions like czechstem.

None.

char_filters

The character filters for the index. Choices are htmlstrip, mapping, and patternreplace.

None.

Usage notes

If the column already contains data, it is indexed during the execution of this statement. After an index has been created, it is automatically updated when data in the column changes.

Indexing with the CREATE INDEX command can impact performance. Before creating an index, be aware of when and when not to create an index.

SAI notes

You can create multiple secondary indexes on the same database table, with each SAI index based on any column in the table. All column date types except the following are supported for SAI indexes:

  • counter

  • Geospatial types: PointType, LineStringType, PolygonType

  • Non-frozen user-defined type (UDT)

You cannot define an SAI index based on the partition key when it’s comprised of only one column. If you attempt to create an SAI index in this case, SAI issues an error message.

Defining one or more SAI indexes based on any column in a database table (with the rules noted above) subsequently gives you the ability to run performant queries that use the indexed column to filter results.

Supported databases for SAI:

Supported databases:

  • Astra DB

  • HCD

  • DataStax Enterprise 6.8.3 and later

  • Cassandra 5.0 and later

SAI supports the following query operators for tables with SAI indexes:

  • Numerics: =, <, >, ⇐, >=, AND

  • Strings: =, AND

  • Collections: =, CONTAINS, CONTAINS KEY

In CQL queries using SAI indexes, the CONTAINS clauses are supported with, and specific to:

  • SAI collection maps with keys, values, and entries

  • SAI collections with list and set types

SAI does not supports the following query operators for tables with SAI indexes:

  • Strings or Numerics: LIKE, OR, IN

For more information about SAI, see the SAI section.

Examples

Detailed examples can be found for each type of indexing:

Index type Example links

SAI

SAI quickstart

primary key

clustering column

non-primary key types

collection types

vector search

2i

primary key

clustering column

non-primary key types

collection types

SASI

primary key

clustering column

non-primary key types

See also

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