Write Delta Stream

R/stream_data.R

stream_write_delta

Description

Writes a Spark dataframe stream into a Delta Lake table.

Usage

stream_write_delta( 
  x, 
  path, 
  mode = c("append", "complete", "update"), 
  checkpoint = file.path("checkpoints", random_string("")), 
  options = list(), 
  partition_by = NULL, 
  ... 
) 

Arguments

Arguments Description
x A Spark DataFrame or dplyr operation
path The path to the file. Needs to be accessible from the cluster. Supports the "hdfs://", "s3a://" and "file://" protocols.
mode Specifies how data is written to a streaming sink. Valid values are "append", "complete" or "update".
checkpoint The location where the system will write all the checkpoint information to guarantee end-to-end fault-tolerance.
options A list of strings with additional options.
partition_by Partitions the output by the given list of columns.
Optional arguments; currently unused.

Details

Please note that Delta Lake requires installing the appropriate package by setting the packages parameter to "delta" in spark_connect()

Examples

library(sparklyr) 
sc <- spark_connect(master = "local", version = "2.4.0", packages = "delta") 
dir.create("text-in") 
writeLines("A text entry", "text-in/text.txt") 
text_path <- file.path("file://", getwd(), "text-in") 
stream <- stream_read_text(sc, text_path) %>% stream_write_delta(path = "delta-test") 
stream_stop(stream) 

See Also

Other Spark stream serialization: stream_read_csv(), stream_read_delta(), stream_read_json(), stream_read_kafka(), stream_read_orc(), stream_read_parquet(), stream_read_socket(), stream_read_text(), stream_write_console(), stream_write_csv(), stream_write_json(), stream_write_kafka(), stream_write_memory(), stream_write_orc(), stream_write_parquet(), stream_write_text()