db.gpapply: Apply a R function to every row of data inside GPDB.

In greenplum-db/GreenplumR: A Fast, Easy-to-Use Tool for Manipulating Tables in Databases

Apply a R function to every row of data inside GPDB.

Description

GPDB will use the PL/Containe or PL/R to run the input R function. An R-wrapper of function will be created as an UDF inside GPDB. The calculation can be done on parallel.

Usage

db.gpapply(X, MARGIN = NULL, FUN = NULL, output.name = NULL, output.signature = NULL,
            clear.existing = FALSE, case.sensitive = FALSE, output.distributeOn = NULL,
            debugger.mode = FALSE, runtime.id = "plc_r_shared", language = "plcontainer", 
            input.signature = NULL, ...)

Arguments

...	The parameter of input function
X	db.data.frame
MARGIN	margin, not used by db.gpapply
FUN	The function to apply each row of db.data.frame
output.name	The name of output table
clear.existing	whether clear existing table stored in db before executing the query
output.signature	The signature of output table, can be a list or a function that takes no parameters. e.g. output.signature <- list(id = 'int', 'Sex' = 'text', 'Length' = 'float', height = 'float', shell = 'float') or output.signature <- function() list(id = 'int')
input.signature	The parameter to match the applying function arguments and table columns' name The pair is function arguments name = table column name e.g. input.signature <- list('arg_f_1' = 'arg_t_1', 'arg_f_2' = 'arg_t_2') NOTICE: The order of both arguments must not change
case.sensitive	Whether output.name, colnames of input tables are case sensitive
output.distributeOn	Specify how output table is stored in database
debugger.mode	Set to TRUE if you want to print the executed SQL internally.
runtime.id	Used by plcontainer only. The runtime id is set by plcontainer to specify a runtime cnofiguration. See plcontainer for more information. e.g. plc_r_shared
language	language used in database e.g. plcontainer

Value

A data.frame that contains the result if the result is not empty. Otherwise, it returns a logical value, which indicates whether the SQL query has been sent to the database successfully.

Author(s)

Author: Pivotal Inc.

Examples

## Not run: 
    db.gptapply(X = dbDF, 
      FUN = function, 
      output.signature = list(id = 'int', 'Sex' = 'text'),
      clear.existing = FALSE, 
      case.sensitive = FALSE,
      output.distributeOn = id,
      ...)

## End(Not run)

greenplum-db/GreenplumR documentation built on Sept. 2, 2023, 8:09 a.m.