class documentation

class SparkHiveDataSet(AbstractDataSet[DataFrame, DataFrame]): (source)

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SparkHiveDataSet loads and saves Spark dataframes stored on Hive. This data set also handles some incompatible file types such as using partitioned parquet on hive which will not normally allow upserts to existing data without a complete replacement of the existing file/partition.

This DataSet has some key assumptions:

  • Schemas do not change during the pipeline run (defined PKs must be present for the duration of the pipeline)
  • Tables are not being externally modified during upserts. The upsert method is NOT ATOMIC

to external changes to the target table while executing. Upsert methodology works by leveraging Spark DataFrame execution plan checkpointing.

Example usage for the YAML API:

hive_dataset:
  type: spark.SparkHiveDataSet
  database: hive_database
  table: table_name
  write_mode: overwrite

Example usage for the Python API:

>>> from pyspark.sql import SparkSession
>>> from pyspark.sql.types import (StructField, StringType,
>>>                                IntegerType, StructType)
>>>
>>> from kedro.extras.datasets.spark import SparkHiveDataSet
>>>
>>> schema = StructType([StructField("name", StringType(), True),
>>>                      StructField("age", IntegerType(), True)])
>>>
>>> data = [('Alex', 31), ('Bob', 12), ('Clarke', 65), ('Dave', 29)]
>>>
>>> spark_df = SparkSession.builder.getOrCreate().createDataFrame(data, schema)
>>>
>>> data_set = SparkHiveDataSet(database="test_database", table="test_table",
>>>                             write_mode="overwrite")
>>> data_set.save(spark_df)
>>> reloaded = data_set.load()
>>>
>>> reloaded.take(4)
Method __getstate__ Undocumented
Method __init__ Creates a new instance of SparkHiveDataSet.
Constant DEFAULT_SAVE_ARGS Undocumented
Static Method _get_spark This method should only be used to get an existing SparkSession with valid Hive configuration. Configuration for Hive is read from hive-site.xml on the classpath. It supports running both SQL and HiveQL commands...
Method _create_hive_table Undocumented
Method _describe Undocumented
Method _exists Undocumented
Method _load Undocumented
Method _save Undocumented
Method _upsert_save Undocumented
Method _validate_save Undocumented
Instance Variable _database Undocumented
Instance Variable _eager_checkpoint Undocumented
Instance Variable _format Undocumented
Instance Variable _full_table_address Undocumented
Instance Variable _save_args Undocumented
Instance Variable _table Undocumented
Instance Variable _table_pk Undocumented
Instance Variable _write_mode Undocumented

Inherited from AbstractDataSet:

Class Method from_config Create a data set instance using the configuration provided.
Method __str__ Undocumented
Method exists Checks whether a data set's output already exists by calling the provided _exists() method.
Method load Loads data by delegation to the provided load method.
Method release Release any cached data.
Method save Saves data by delegation to the provided save method.
Method _copy Undocumented
Method _release Undocumented
Property _logger Undocumented
def __getstate__(self): (source)

Undocumented

def __init__(self, database: str, table: str, write_mode: str = 'errorifexists', table_pk: List[str] = None, save_args: Dict[str, Any] = None): (source)

Creates a new instance of SparkHiveDataSet.

Note

For users leveraging the upsert functionality, a checkpoint directory must be set, e.g. using spark.sparkContext.setCheckpointDir("/path/to/dir") or directly in the Spark conf folder.

Parameters
database:strThe name of the hive database.
table:strThe name of the table within the database.
write_mode:strinsert, upsert or overwrite are supported.
table_pk:List[str]If performing an upsert, this identifies the primary key columns used to resolve preexisting data. Is required for write_mode="upsert".
save_args:Dict[str, Any]Optional mapping of any options, passed to the DataFrameWriter.saveAsTable as kwargs. Key example of this is partitionBy which allows data partitioning on a list of column names. Other HiveOptions can be found here: https://spark.apache.org/docs/latest/sql-data-sources-hive-tables.html#specifying-storage-format-for-hive-tables
Raises
DataSetErrorInvalid configuration supplied
DEFAULT_SAVE_ARGS: Dict[str, Any] = (source)

Undocumented

Value
{}
@staticmethod
def _get_spark() -> SparkSession: (source)

This method should only be used to get an existing SparkSession with valid Hive configuration. Configuration for Hive is read from hive-site.xml on the classpath. It supports running both SQL and HiveQL commands. Additionally, if users are leveraging the upsert functionality, then a checkpoint directory must be set, e.g. using spark.sparkContext.setCheckpointDir("/path/to/dir")

def _create_hive_table(self, data: DataFrame, mode: str = None): (source)

Undocumented

def _describe(self) -> Dict[str, Any]: (source)

Undocumented

def _exists(self) -> bool: (source)

Undocumented

def _load(self) -> DataFrame: (source)

Undocumented

def _save(self, data: DataFrame): (source)

Undocumented

def _upsert_save(self, data: DataFrame): (source)

Undocumented

def _validate_save(self, data: DataFrame): (source)

Undocumented

_database = (source)

Undocumented

_eager_checkpoint = (source)

Undocumented

Undocumented

_full_table_address = (source)

Undocumented

_save_args = (source)

Undocumented

Undocumented

_table_pk = (source)

Undocumented

_write_mode = (source)

Undocumented