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Types

A type is analogous to a traditional database schema for a table. Before data can be stored in Kinetica, a type must be specified for that data. For every type, Kinetica assigns a unique GUID. Kinetica will use the same GUID for all types with identical characteristics.

Every type in Kinetica consists of the following:

  • Type Label (text to identify this type)
  • Type Schema (list of attributes with their primitive types)
  • Annotation (Security) Attribute (optional)

Type Label

A type label serves as a tagging mechanism for the type. The type label can be any text string specified by the client. The type label serves two purposes. First, it identifies tables with similar data. Second, it helps determine a type’s uniqueness.

Type Schema

A type schema consists of a set of column names and their respective primitive types. Each column can also be assigned a number of pre-defined properties that determine aspects of that column, like searchability and whether or not the column is indexed.

Primitive Types

A given column in a type schema must be of one of the following primitive types:

Base Type Native Type Bytes in Memory Minimum Value Maximum Value
int integer (default) 4 -2147483648 2147483647
int16 2 -32768 32767
int8 1 -128 127
long long (default) 8 -9223372036854775808 9223372036854775807
timestamp 8

-30610224000000

(1/1/1000 00:00:00.000)

29379542399999

(12/31/2900 23:59:59.999)

float float (default) 4 -3.40282 * 1038 3.40282 * 1038
double double (default) 8 -1.79769313486231 * 10308 1.79769313486231 * 10308
string string (default) 8 (empty string) (100,000,000,000 characters)
char256 256 (empty string) (256 characters)
char128 128 (empty string) (128 characters)
char64 64 (empty string) (64 characters)
char32 32 (empty string) (32 characters)
char16 16 (empty string) (16 characters)
char8 8 (empty string) (8 characters)
char4 4 (empty string) (4 characters)
char2 2 (empty string) (2 characters)
char1 1 (empty string) (1 character)
ipv4 4 0.0.0.0 255.255.255.255
decimal 8 -922337203685477.5808 922337203685477.5807
date 4 1000-01-01 2900-12-31
time 4 00:00:00.000 23:59:59.999
datetime 8 1000-01-01 00:00:00.000 2900-12-31 23:59:59.999
wkt varies (empty string) (100,000,000,000 characters)
bytes bytes (default) N/A (empty array) (100,000,000,000 bytes)
wkt varies (empty array) (100,000,000,000 bytes)

Note

Adding nullability to a column requires an additional byte per value; e.g., a nullable integer requires 5 bytes in memory instead of 4.

Decimal Type

The decimal type should be used instead of float or double when exact values need to be stored and rounding errors are unacceptable, such as currency.

Decimal fields are supported by most, but not all, endpoint functions. Those that currently support decimal are:

Column Properties

Kinetica has an additional layer of semantic regarding column data type. At the time of creation, a column can be given one or more of the supported properties, which give the column special meaning or handling. The properties can refine the data type, direct special handling, or define the keyed nature of the column. These modifiers can impact the number of records that can be stored in memory, the performance of queries, and the types of operations that can be performed on the data.

Data Types

The following properties can be used to modify the allowable set of values for the corresponding base type. Only one of the following properties may be applied to a given column, and the column must be of the stated base type. The exception to this is nullability, which can be applied to any column in addition to the data type specifiers listed here. However, nullable is not used at type creation, but will be returned in a /show/table call. Denoting a column's nullability is API-dependent, and, with the exception of the Java API, does not involve the direct use of the nullable column property.

Property Base Type Description
char1 string Text of up to 1 character; optimizes memory, disk, and query performance
char2 string Text of up to 2 characters; optimizes memory, disk, and query performance
char4 string Text of up to 4 characters; optimizes memory, disk, and query performance
char8 string Text of up to 8 characters; optimizes memory, disk, and query performance
char16 string Text of up to 16 characters; optimizes memory, disk, and query performance
char32 string Text of up to 32 characters; optimizes memory, disk, and query performance
char64 string Text of up to 64 characters; optimizes memory, disk, and query performance
char128 string Text of up to 128 characters; optimizes memory, disk, and query performance
char256 string Text of up to 256 characters; optimizes memory, disk, and query performance
date string Interprets a string field as a date of the form YYYY-MM-DD
datetime string Interprets a string field as a combination of date and time in the form of YYYY-MM-DD HH:MM:SS[.mmm]
decimal string Interprets a string field as a decimal number, with up to 19 digits of precision and 4 digits of scale
int8 int Numbers limited to 8-bit signed integers; optimizes memory and query performance
int16 int Numbers limited to 16-bit signed integers; optimizes memory and query performance
ipv4 string Dotted decimal IPv4 addresses of the form: A.B.C.D where A, B, C and D are between 0 and 255, inclusive (e.g. 127.0.0.1); optimizes memory, disk, and query performance
nullable <any>

Values can be set to null

Note: This property is generally not used in column creation; assigning nullability is an API-dependent exercise

time string Interprets a string field as a time of the form HH:MM:SS[.mmm]
timestamp long Timestamps in milliseconds since the Unix epoch: Jan 1 1970 00:00:00
wkt string or bytes Indicates that the column has WKT (or WKB) strings that should be handled as geometry objects.

Data Handling

One or more of the following properties can be assigned to a column to alter the way the data is stored & handled. Valid combinations are detailed in the descriptions.

Property Description
data Directs that the column's data should be stored in memory, making it available for use in query expressions. Default property for all numeric and string type columns, unless overridden by store_only.
dict This property will dictionary encode the associated charN, int, long, or date column, reducing memory and disk usage. Queries against the column will also be faster. For Dictionary Encoding details, see Dictionary Encoding.
disk_optimized Prevents variable-width strings from being written to an indexing service, saving disk space at the cost of some functionality. A /filter/bystring applied will only work in the equals mode, /aggregate/unique cannot be applied, and /aggregate/groupby can only be used when the count or count_distinct function is applied to the column--the column itself cannot otherwise appear in the column list. Requires the data property.
store_only Reduces system memory usage by not keeping a copy of the data in memory and only persisting the values. The data is able to be queried by column name, but since not in memory, no expressions (column, filter, aggregation, etc.) can be applied. It is mutually exclusive with the data property. Default property for bytes type columns.
text_search Enables full text search for string columns. Can be set independently of data, disk_optimized, & store_only. For full text search details and limitations, see Full Text Search.

Data Keys

One or both of these keyed attributes can be assigned to one or more columns. For more information, see the sections on primary keys & shard keys. Foreign keys cannot be assigned as column properties.

Property Description
primary_key Makes this column part of (or the entire) primary key
shard_key Makes this column part of (or the entire) shard key

Data Replacement

The following property can be assigned to a column to replace certain kinds of data.

Property Description
init_with_now For date, time, datetime, and timestamp columns, this property will replace empty strings and invalid timestamp values with NOW().