About Connector Options

You provide Greenplum Database connection options and the read/write options required by the Greenplum-Spark Connector via generic key-value String pairs.

The Greenplum-Spark Connector supports the options identified in the table below. An option is required unless otherwise specified.

Option Key Value Description Operation
url The JDBC connection string URL; see Constructing the Greenplum Database JDBC URL. Read, Write
dbschema The name of the Greenplum Database schema in which dbtable resides. This option also identifies the name of the schema in which the Greenplum-Spark Connector creates temporary external tables. Optional, the default schema is the schema named public. Read, Write
dbtable The name of the Greenplum Database table. When reading from Greenplum Database, this table must reside in the Greenplum Database schema identified in the dbschema option value. When writing from Spark to Greenplum Database, the Greenplum-Spark Connector creates the table in dbschema if the table does not already exist. Read, Write
driver The fully qualified class path of the custom JDBC driver. Optional, specify only when using a custom JDBC driver. Read, Write
user The Greenplum Database user/role name. Read, Write
password The Greenplum Database password for the user. You can omit the password if Greenplum Database is configured to not require a password for the specified user, or if you use kerberos authentication and provide the required authentication properties in the JDBC connection string URL. Optional. Read, Write
partitionColumn The name of the Greenplum Database table column to use for Spark partitioning. This column must be one of the Greenplum Database data types integer, bigint, serial, or bigserial. The column name must be lowercase. Read
partitionsPerSegment The number of Spark partitions per Greenplum Database segment. Optional, the default value is 1 partition. Read
connector.port The port number, or the environment variable name that identifies such, that the Greenplum-Spark Connector should use for data transfer to/from Spark worker nodes. Optional, by default the Connector uses a random port. Read, Write
pool.maxSize The maximum number of connections in the connection pool. Optional, the default value is 64. Read, Write
pool.timeoutMs The amount of time, in milliseconds, after which an inactive connection is considered idle. Optional, the default value is 10,000 (10 seconds). Read, Write
pool.minIdle The minimum number of idle connections maintained in the connection pool. Optional, the default value is 0. Read, Write

You can specify options to the Connector individually or in an options Map. The class methods of interest for setting Greenplum-Spark Connector options are:

.option(key: String, value: String)

for specifying an individual option, and:

.options(options: Map[String, String])

for specifying an options map.

To specify an option individually, provide <option_key> and <value> strings to the DataFrameReader.option() method. For example, to specify the user option:

.option("user", "gpdb_role_name")

To construct a scala.collection.Map comprising more than one option, you provide the <option_key> and <value> strings for each option. For example, to create the options for a read operation:

val gscReadOptionMap = Map(
      "url" -> "jdbc:postgresql://gpdb-master:5432/testdb",
      "user" -> "bill",
      "password" -> "changeme",
      "dbschema" -> "myschema",
      "dbtable" -> "table1",
      "partitionColumn" -> "id"
)

To provide an options map to the Connector, specify it in the DataFrameReader.options() or DataFrameWriter.options() methods. For example, to provide the gscReadOptionMap map created above:

.options(gscReadOptionMap)

Specifying Partition Options

Partition options apply only when you read data from Greenplum Database into Spark.

A Spark DataFrame is a fault-tolerant collection of elements partitioned across the Spark cluster nodes. Spark operates on these elements in parallel.

Greenplum Database distributes its table data across segments running on segment hosts.

The Greenplum-Spark connector provides two options to configure the mapping between Spark partitions and Greenplum Database segment data, partitionColumn and partitionsPerSegment.

partitionColumn

The partitionColumn option that you specify must have the integer, bigint, serial, or bigserial Greenplum Database data type. The partitionColumn you identify need not be the column specified with the DISTRIBUTED BY (<column>) clause when you created the Greenplum Database table.

partitionsPerSegment

By default, the Greenplum-Spark Connector creates one Spark partition per Greenplum Database segment. You can set the partitionsPerSegment option to specify a larger number of Spark partitions.

Spark partitions have a 2 GB size limit. If you are using the Connector to move more than 2 GB of data per Greenplum Database segment, you must increase the partitionsPerSegment option value appropriately.

Specifying the connector.port Option

Use the connector.port option to specify the port number that the Greenplum-Spark Connector uses for data transfer between Greenplum Database and Spark worker nodes.

Option Key Value Description
connector.port The port number or the environment variable name that identifies such, that the Greenplum-Spark Connector should use for data transfer to/from Spark worker nodes. Optional, by default the Connector uses a random port.

You can specify a port number or an environment variable name for the connector.port option. To set a port number, identify the specific port number. For example, to set the connector.port as a single option:

.option("connector.port", "12900")

Or, to set within a Map of options:

"connector.port" -> "12900"

If you choose to specify the port number with an environment variable, prefix the environment variable name with env.. For example, to identify the environment variable named GSC_EXTERNAL_PORT as the connector.port option value:

"connector.port" -> "env.GSC_EXTERNAL_PORT",

Note: Setting connector.port to env.GPFDIST_PORT results in the same behavior as that of Greenplum-Spark Connector version 1.2.0.

Refer to Configuring Spark Worker Ports for additional information about the connector.port option.

Specifying Connection Pool Options

The Greenplum-Spark Connector provides connection pool configuration options. These options are named with the pool. prefix:

Option Key Value Description
pool.maxSize The maximum number of connections in the connection pool. Optional, the default value is 64.
pool.timeoutMs The amount of time, in milliseconds, after which an inactive connection is considered idle. Optional, the default value is 10,000 (10 seconds).
pool.minIdle The minimum number of idle connections maintained in the connection pool. Optional, the default value is 0.

To set each connection pool option as a single option:

.option("pool.maxSize", "50")
.option("pool.minIdle", "5")
.option("pool.timeoutMs", "7500")

The first DataFrame that you create with a specific connection string URL, username, and password combination defines the configuration of that connection pool. The Greenplum-Spark Connector ignores connection pool options specified on subsequent DataFrames created with the same URL/username/password combination.

Refer to JDBC Connection Pooling for additional information about connection pool configuration options.