Load a streaming SparkDataFrame

Returns the dataset in a data source as a SparkDataFrame

Usage

read.stream(source = NULL, schema = NULL, ...)

Arguments

source: The name of external data source
schema: The data schema defined in structType or a DDL-formatted string, this is required for file-based streaming data source
...: additional external data source specific named options, for instance path for file-based streaming data source. timeZone to indicate a timezone to be used to parse timestamps in the JSON/CSV data sources or partition values; If it isn't set, it uses the default value, session local timezone.

Value

SparkDataFrame

Details

The data source is specified by the source and a set of options(...). If source is not specified, the default data source configured by "spark.sql.sources.default" will be used.

Note

read.stream since 2.2.0

experimental

Examples

if (FALSE) {
sparkR.session()
df <- read.stream("socket", host = "localhost", port = 9999)
q <- write.stream(df, "text", path = "/home/user/out", checkpointLocation = "/home/user/cp")

df <- read.stream("json", path = jsonDir, schema = schema, maxFilesPerTrigger = 1)
stringSchema <- "name STRING, info MAP<STRING, DOUBLE>"
df1 <- read.stream("json", path = jsonDir, schema = stringSchema, maxFilesPerTrigger = 1)
}