Batch processing typically leads to further interactive exploration, provides the modeling-ready data for machine learning, or writes the data to a data store that is optimized for analytics and visualization. One example of batch processing is transforming a large set of flat, semi-structured CSV or JSON files into a schematized and structured format that is ready for further querying.
Typically the data is converted from the raw formats used for ingestion such as CSV into binary formats that are more performant for querying because they store data in a columnar format, and often provide indexes and inline statistics about the data. Data format and encoding. Some of the most difficult issues to debug happen when files use an unexpected format or encoding.
For example, source files might use a mix of UTF and UTF-8 encoding, or contain unexpected delimiters space versus tab , or include unexpected characters. Another common example is text fields that contain tabs, spaces, or commas that are interpreted as delimiters. Data loading and parsing logic must be flexible enough to detect and handle these issues.
Orchestrating time slices. Often source data is placed in a folder hierarchy that reflects processing windows, organized by year, month, day, hour, and so on.
In some cases, data may arrive late. For example, suppose that a web server fails, and the logs for March 7th don't end up in the folder for processing until March 9th. Are they just ignored because they're too late? Can the downstream processing logic handle out-of-order records? A batch processing architecture has the following logical components, shown in the diagram above. Data storage. Typically a distributed file store that can serve as a repository for high volumes of large files in various formats.
In File Name Separator for an open batch, select the character to use when separating the five segments of an open batch file name. Select Auto Create Data Rule to create the data rule automatically for file-based data loads. The Auto Create Data Rule option is available when the rule type is "open batch". If this name does not exist, Data Management creates the data rule using the following file naming conventions:. Optional: In the Description field, enter a description of the batch definition.
Optional : In Batch Group , select the batch group to associate with the batch. Optional : In Number of Parallel Jobs , specify the maximum number of parallel processes submitted by a batch at any time.
This option is used in conjunction with the Wait for Completion and Timeout fields. If Wait for Completion and a time-out period options are set, but the number of parallel jobs is not, then Data Management waits for all batch jobs to complete and then returns control. If the wait time is reached before all the jobs are complete, the system exits the batch processing procedure.
The Wait for Completion setting is not for each subset, but for the whole batch. For example, let's suppose you have 20 jobs where the number of parallel jobs is set to 4 and the time-out period is 10 M. If only 15 jobs are completed in 10 M, the system still exits. If No Wait is specified, the system submits all jobs and returns control submitted immediately without waiting for any running processes to finish.
In Parameters , select Import From Source to import the data from the source system, perform the necessary transformations, and export the data to the Data Management staging table. Select Export To Target to export the data to the target application. When setting up a batch, you can choose the POV to drive the period, or enter the periods explicitly. Specify dates in the Start Period and End Period to derive period parameters through which the data is processed.
Use the date format based on the locale settings for your locale. In the Import Mode drop-down, select the mode to extract data all at once for an entire period or incrementally during the period.
For a Planning application, Replace Data clears data for the Year, Period, Scenario, Version, and Entity dimensions that you are loading, and then loads the data from the source or file. Note when you have a year of data in your Planning application but are only loading a single month, this option clears the entire year before performing the load.
Select Extract Exchange Rate to extract the exchange rate. This option is not applicable for file-based source systems. In the Export Mode drop-down, select the mode of exporting data. For Planning applications, in the Export Mode drop-down, select the mode of exporting data. This is confusing if additional code should run after the batch file is called. Unlike Linux shell scripts that use!
By default, when the batch file is run, each line is echoed to standard output. This tends to be overwhelming and therefore the following first line is typically used to turn off echoing output:.
A batch file is entered at the first line. Each command is processed in order unless control commands such as goto or other code blocks influence the program flow. The following example illustrates typical code organization. Using rem at the beginning of a line can be indented indicates that the line is a comment. Variables in batch files are defined using syntax similar to the following.
It is possible to use data types such as strings, integers, and floating point numbers; however, strings are the simplest to deal with, for example:. By default, variable values are set when lines are parsed, which is a holdover of behavior from early versions of the software. However, this behavior does not work properly when for loops and other complex logic are used. Consequently the setlocal syntax was added later. The logic control features of batch files are not as easy to use as those of Linux scripts, although with experience it is possible to write batch files that are modular and highly functional.
The terms "commmand" and "program" may be used interchangeably and cause confusion. The cmd program, which is actually an executable program named cmd.
For example, the if statement is so fundamental to the cmd shell's functionality that it is compiled into the program. The dir command is a foundational command and is also compiled into the shell. This can be verified by running:. In contrast, the taskmgr program is an external program and when run from command prompt displays the Task Manager.
Built-in commands and statements are compiled into the cmd program, whereas external programs are located using the PATH environment variable. The exit statement exits a batch file or function, optionally with an integer return code. It is typically to use a 0 zero exit code to indicate success, and 1 or other non-zero value to indicate an error. Some programs use specific error code values to communicate the error type with calling code. It is also useful to put one ore more variants of exit label at the end of the batch file, which can be jumped to from logic do not use a label named :exit because this seems to confuse the cmd shell.
The following is an example of using exit :. The if statement performs conditional processing in batch files so that logic decisions can be made. A typical example is to compare the value of a string to a variable and jump to another point in the batch file. In the following example, string1 and string2 are literal strings. They do not need to be surrounded by double quotes.
A single line if command such as the above allows only simple logic. The following example shows an if statement that uses parentheses to create a multi-line logic block. This example uses the exists condition to check for file existence. It is also possible to perform more complex logic using if and else statements.
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