db.gptapply: Data inside GPDB is group by a selected index. A R function...

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

Data inside GPDB is group by a selected index. A R function is applied to every row of grouped data.

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.gptapply(X, INDEX, 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
INDEX	The index
FUN	The input function
output.name	The name of output table
output.signature	The parameter of output table e.g. output.signature <- list(id = 'int', 'Sex' = 'text', 'Length' = 'float', height = 'float', shell = 'float')
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, etc. are case sensitive
clear.existing	whether clear existing table stored in db before executing the query
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, 
      "id", 
      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.