Snowflake

JDBC Snowflake Source Connector​

Key Features

• batch

• stream

• exactly-once

• column projection

• parallelism

• support user-defined split

supports query SQL and can achieve projection effect.​

Description​

Read external data source data through JDBC.

Data Type Mapping

Snowflake Data type	Nexus Data type
BOOLEAN	BOOLEAN
TINYINT SMALLINT BYTEINT	SHORT_TYPE
INT INTEGER	INT
BIGINT	LONG
DECIMAL NUMERIC NUMBER	DECIMAL(x,y)
DECIMAL(x,y)(Get the designated column's specified column size.>38)	DECIMAL(38,18)
REAL FLOAT4	FLOAT
DOUBLE DOUBLE PRECISION FLOAT8 FLOAT	DOUBLE
CHAR CHARACTER VARCHAR STRING TEXT VARIANT OBJECT	STRING
DATE	DATE
TIME	TIME
DATETIME TIMESTAMP TIMESTAMP_LTZ TIMESTAMP_NTZ TIMESTAMP_TZ	TIMESTAMP
BINARY VARBINARY	BYTES
GEOGRAPHY (WKB or EWKB) GEOMETRY (WKB or EWKB)	BYTES
GEOGRAPHY (GeoJSON, WKT or EWKT) GEOMETRY (GeoJSON, WKB or EWKB)	STRING

Options​

name	type	required	default	description
url	String	Yes	-	The URL of the JDBC connection. Refer to a case: jdbc:snowflake://<account_name>.snowflakecomputing.com
driver	String	Yes	-	The jdbc class name used to connect to the remote data source, if you use Snowflake the value is net.snowflake.client.jdbc.SnowflakeDriver.
user	String	No	-	Connection instance user name
password	String	No	-	Connection instance password
query	String	Yes	-	Query statement
connection_check_timeout_sec	Int	No	30	The time in seconds to wait for the database operation used to validate the connection to complete
partition_column	String	No	-	The column name for parallelism's partition, only support numeric type,Only support numeric type primary key, and only can config one column.
partition_lower_bound	BigDecimal	No	-	The partition_column min value for scan, if not set Nexus will query database get min value.
partition_upper_bound	BigDecimal	No	-	The partition_column max value for scan, if not set Nexus will query database get max value.
partition_num	Int	No	job parallelism	The number of partition count, only support positive integer. default value is job parallelism
fetch_size	Int	No	0	For queries that return a large number of objects,you can configure the row fetch size used in the query toimprove performance by reducing the number database hits required to satisfy the selection criteria. Zero means use jdbc default value.
properties	Map	No	-	Additional connection configuration parameters,when properties and URL have the same parameters, the priority is determined by the specific implementation of the driver. For example, in MySQL, properties take precedence over the URL.
common-options		No	-	Source plugin common parameters, please refer to Source Common Options for details

tips​

If partition_column is not set, it will run in single concurrency, and if partition_column is set, it will be executed in parallel according to the concurrency of tasks.

JDBC Driver Connection Parameters are supported in JDBC connection string. E.g, you can add ?GEOGRAPHY_OUTPUT_FORMAT='EWKT' to specify the Geospatial Data Types. For more information about configurable parameters, and geospatial data types please visit Snowflake official document

Task Example​

simple:​

This example queries type_bin 'table' 16 data in your test "database" in single parallel and queries all of its fields. You can also specify which fields to query for final output to the console.

# Defining the runtime environment
env {
parallelism = 2
job.mode = "BATCH"
}
source{
Jdbc {
url = "jdbc:snowflake://<account_name>.snowflakecomputing.com"
driver = "net.snowflake.client.jdbc.SnowflakeDriver"
connection_check_timeout_sec = 100
user = "root"
password = "123456"
query = "select * from type_bin limit 16"
}
}
transform {
# If you would like to get more information about how to configure Nexus and see full list of transform plugins,
# please go to transform page
}
sink {
Console {}
}

parallel:​

Read your query table in parallel with the shard field you configured and the shard data You can do this if you want to read the whole table

Jdbc {
url = "jdbc:snowflake://<account_name>.snowflakecomputing.com"
driver = "net.snowflake.client.jdbc.SnowflakeDriver"
connection_check_timeout_sec = 100
user = "root"
password = "123456"
# Define query logic as required
query = "select * from type_bin"
# Parallel sharding reads fields
partition_column = "id"
# Number of fragments
partition_num = 10
}

parallel boundary:​

It is more efficient to specify the data within the upper and lower bounds of the query It is more efficient to read your data source according to the upper and lower boundaries you configured

Jdbc {
url = "jdbc:snowflake://<account_name>.snowflakecomputing.com"
driver = "net.snowflake.client.jdbc.SnowflakeDriver"
connection_check_timeout_sec = 100
user = "root"
password = "123456"
# Define query logic as required
query = "select * from type_bin"
partition_column = "id"
# Read start boundary
partition_lower_bound = 1
# Read end boundary
partition_upper_bound = 500
partition_num = 10
}