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Design concepts
Learn about HCL Link services, projects, flows, maps and schemas.
Maps
A HCL Link map defines how to generate data that complies to a specific schema. A map can have any number of inputs and outputs.
Performance recommendations
This documentation contains general performance tips and recommendations to improve performance.
General performance overview
This documentation describes what takes place during product execution and presents performance tips and recommendations regardless of the platform on which a specific HCL Link product is running.
Command Server operation overview
The first step in trying to achieve performance improvements running the Command Server in your environment is to understand Command Server operation.
Command Server paging settings
To minimize the memory footprint during transformation, HCL Link keeps only a subset of the work and data file information in memory at a given time.
Scenario: configure paging by input file size
The following test scenario was created to demonstrate how the input size might require a larger information window or page setting, so it does not impact performance.

Design concepts
Learn about HCL Link services, projects, flows, maps and schemas.
- Introduction
  The documentation provided here defiens the main artifacts in HCL Link. It is necessar to understand what these artifacts are and the relationship between them.
- Services
  Service definitions define REST services and the endpoints of a service.
- Projects
  A project is a container for HCL Link artifacts.
- Flows
  A HCL Link flow is a transactional data flow comprised of processing nodes.
- Maps
  A HCL Link map defines how to generate data that complies to a specific schema. A map can have any number of inputs and outputs.
  - Define mapping between source and target
    This documentation describes how to use HCL Link to define mapping between source and target.
  - Auto-mapper
    The Auto-mapper functionality allows for similarly named fields to be automatically mapped from inputs to outputs. This alleviates the need to manually map each field individually.
  - Performance recommendations
    This documentation contains general performance tips and recommendations to improve performance.
    - General performance overview
      This documentation describes what takes place during product execution and presents performance tips and recommendations regardless of the platform on which a specific HCL Link product is running.
      - Performance measurement factors
        When analyzing how well an application has performed, there are potentially a large number of measurements that can be used to gauge workload efficiency in terms of the specific resources the application used.
      - Command Server operation overview
        The first step in trying to achieve performance improvements running the Command Server in your environment is to understand Command Server operation.
        Command Server execution overview
        When you want to achieve performance improvements when running the Command Server in your environment, you must understand Command Server execution.
        Command Server work and data files
        Depending on the conditions of the transformation, such as input data file size and processing complexity, work and data files can significantly affect performance.
        Command Server paging settings
        To minimize the memory footprint during transformation, HCL Link keeps only a subset of the work and data file information in memory at a given time.
        Paging and I/O usage
        Paging controls the amount of data available to the transformation portion of the map execution at any time. If a map rule requires a piece of data that is not in memory, the paging subsystem will fetch the appropriate data from disk. This can impact existing data in memory; if there are no unused pages, an existing page is swapped out of memory.
        Scenario: configure paging by input file size
        The following test scenario was created to demonstrate how the input size might require a larger information window or page setting, so it does not impact performance.
        Configuring optimal page subsystem settings
        The settings for the paging subsystem in HCL Link can determine whether a transformation process runs bound by I/O bandwidth or by CPU capacity. These settings can impact system performance.
        WorkSpace in Memory option
        The WorkSpace in Memory option can be a viable choice for reducing I/O usage during transformation if enough memory is available. With a smaller input data file, the transformation engine can attempt to process the work file entirely in memory.
      - Map performance and tuning best practices
        Many functions available to users for developing HCL Link maps are very powerful and can perform difficult and complicated tasks. Some functions may sacrifice performance for powerful capabilities, and it is important to understand the implications of these.
- Schemas
  Schemas specify the format of data witin HCL Link maps and flows.
- Connections and Actions
  This documentation describes connections and actions.
- Files
  Files are used in various places within HCL Link. HCL Link allows files to be uploaded to the HCL Linkserver.
- Flow variables
  Flow variables provide a means of passing information throughout a flow instance without requiring that the information to be passed through data links. flow variables are name-value pairs that persist, unless deleted.
- Cache variables
  Cache variables provide a means of processing information throughout a flow instance without requiring that the information to be passed through data links.

Scenario: configure paging by input file size

The following test scenario was created to demonstrate how the input size might require a larger information window or page setting, so it does not impact performance.

Two test cases were created and then executed using the same testing procedures.

Maps: The same map is used in both tests.
Inputs: There are two input data files.
- Input 1 size: 3 MB
- Input 2 size: 11 MB
Process:
- Map performed a number of operations such as a large number of EXTRACT() calls that spanned each of the input data files.
- These requests mandated that a certain percentage of the input data be available at any given time for optimal performance.
Objective:
- Determine the page size to get the optimal execution time for each of the input data files.
Test Case 1 Result:
- Quantitative measurement of execution time at various page counts and sizes identified an optimal execution time at the following workpage settings for the 3 MB input data file: size 64 K and count 12. This is represented by -P64:12, where -P is WorkSpace Paging, 64 is the page size and 12 is the page count.
Test Case 2 Result:
- The same testing procedure found -P64:53 to produce the optimal execution time for the 11 MB input data file.
Conclusion:
- Paging settings depend on input data size just as much as they do on the map rules. An optimal page setting for a given map and data file might not be optimal for the same map with a much larger or smaller data file.