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Data Types

GreptimeDB supports the following data types:

Type nameDescriptionSynonyms
tinyint8-bit signed small integers between -128~127
smallint16-bit signed big integers between -32768~32767
int32-bit signed integers between -2147483648~2147483647integer
bigint64-bit signed big integers between -9223372036854775808~9223372036854775807
varcharUTF-8 encoded stringstext/string/char
float32-bit IEEE754 floating point values
doubleDouble precision IEEE 754 floating point values
booleanBoolean values
varbinaryVariable length binary values
date32-bit date values
datetime64-bit datetime values
timestamp64-bit timestamp values with millisecond precision

Unsigned version of integer types

int / tinyint / smallint / bigint also have unsigned version, and there corresponding value ranges are:

  • int unsigned: 0~4294967295
  • tinyint unsigned: 0~255
  • smallint unsigned: 0~65535
  • bigint unsigned: 0~18446744073709551615

Variable-sized type limitations

The max capacities of variable-sized type, such as string and varbinary are determined by their encodings and how storage engine handles them.

For example, string values are encoded into UTF-8. If all characters are 3-bytes lengthed, this field can store 715827882 characters. As for varbinary types, it can store 2147483647 bytes at most.

Choose the data type for timestamp column

GreptimeDB allows user to choose bigint or timestamp for timestamp index column. Both bigint and timestamp are interpreted as timestamp in millisecond precision.

SQL
# using TIMESTAMP as timestamp column data type
CREATE TABLE monitor (
    host STRING,
    ts TIMESTAMP, 
    cpu DOUBLE DEFAULT 0,
    memory DOUBLE,
    TIME INDEX (ts),
    PRIMARY KEY(host)) ENGINE=mito WITH(regions=1);

# using BIGINT as timestamp column data type is also allowed
CREATE TABLE monitor (
    host STRING,
    ts BIGINT, 
    cpu DOUBLE DEFAULT 0,
    memory DOUBLE,
    TIME INDEX (ts),
    PRIMARY KEY(host)) ENGINE=mito WITH(regions=1);