spark_read_parquet
Read a Parquet file into a Spark DataFrame
Read a Parquet file into a Spark DataFrame.
Usage
spark_read_parquet(
sc,
name = NULL,
path = name,
options = list(),
repartition = 0,
memory = TRUE,
overwrite = TRUE,
columns = NULL,
schema = NULL,
...
)Arguments
- sc
A
spark_connection.- name
The name to assign to the newly generated table.
- path
The path to the file. Needs to be accessible from the cluster. Supports the "hdfs://", "s3a://" and "file://" protocols.
- options
A list of strings with additional options. See http://spark.apache.org/docs/latest/sql-programming-guide.html#configuration.
- repartition
The number of partitions used to distribute the generated table. Use 0 (the default) to avoid partitioning.
- memory
Boolean; should the data be loaded eagerly into memory? (That is, should the table be cached?)
- overwrite
Boolean; overwrite the table with the given name if it already exists?
- columns
A vector of column names or a named vector of column types. If specified, the elements can be
"binary"forBinaryType,"boolean"forBooleanType,"byte"forByteType,"integer"forIntegerType,"integer64"forLongType,"double"forDoubleType,"character"forStringType,"timestamp"forTimestampTypeand"date"forDateType.- schema
A (java) read schema. Useful for optimizing read operation on nested data.
- ...
Optional arguments; currently unused.
Details
You can read data from HDFS (hdfs://), S3 (s3a://), as well as
the local file system (file://).
If you are reading from a secure S3 bucket be sure to set the following in your spark-defaults.conf
spark.hadoop.fs.s3a.access.key, spark.hadoop.fs.s3a.secret.key or any of the methods outlined in the aws-sdk
documentation Working with AWS credentials
In order to work with the newer s3a:// protocol also set the values for spark.hadoop.fs.s3a.impl and spark.hadoop.fs.s3a.endpoint .
In addition, to support v4 of the S3 api be sure to pass the -Dcom.amazonaws.services.s3.enableV4 driver options
for the config key spark.driver.extraJavaOptions
For instructions on how to configure s3n:// check the hadoop documentation:
s3n authentication properties
See Also
Other Spark serialization routines:
spark_load_table(),
spark_read_avro(),
spark_read_csv(),
spark_read_delta(),
spark_read_jdbc(),
spark_read_json(),
spark_read_libsvm(),
spark_read_orc(),
spark_read_source(),
spark_read_table(),
spark_read_text(),
spark_read(),
spark_save_table(),
spark_write_avro(),
spark_write_csv(),
spark_write_delta(),
spark_write_jdbc(),
spark_write_json(),
spark_write_orc(),
spark_write_parquet(),
spark_write_source(),
spark_write_table(),
spark_write_text()