Understanding The LEADTOOLS Job Processor Database - Namespace - Raster, Medical, Document Help

Understanding The LEADTOOLS Job Processor Database

The Job Processor database is responsible for storing any information related to jobs in the Job Processor. The LEADTOOLS Distributed Computing (Job Processor) SDK will handle all communication with the database but in some cases, you may want to create a relationship between the Job Processor's JobTable and another table in your application. Refer to the following table for column definitions and usage.

Using Multiple Job Types

Each Windows Service can be set up to process any number of job types. There are no limitations to the number of Windows Services from the LEADTOOLS Distributed Computing Framework which can be installed on a single machine. In a typical scenario, a job type is configured for each unique task the Job Processor is designed to process.

For example, you could set up one job type for performing OCR, and another job type for converting multimedia files. One option would be to create a single worker assembly capable of handling both types of jobs. Your assembly would simply identify the job type of the job and process it accordingly. Another option would be to create a worker assembly for each type of job. Each windows service can only be configured to load a single worker assembly. However, if you choose to use multiple worker assemblies, you would need to set up a windows service for each type of job. Regardless of the configuration you choose, all windows services can share the same central server and database.

As an example, consider a case where the Job Processor is converting files from one format to another, but the files are located at a remote location and must first be downloaded. One solution is to configure a single job type which first downloads the file and then converts it, all in a single pass. An alternative would be to split these two tasks into separate job types. The advantage of splitting these tasks is that doing so allows each task to be controlled independently. For example, perhaps you want only 4 files to be downloaded at any one time, but want to convert 8 files at one time. The workflow would look like the following:

  1. A client adds a new "Download" job.

  2. The job is picked up by a worker configured to accept "Download" jobs.

  3. After the worker assembly has downloaded the file, it will call the ResetJob Method with a new, "Convert" job. Calling ResetJob will also update the status of the job to JobStatus.New, indicating it is again ready for processing.

  4. The job is picked up by a worker configured to accept "Convert" jobs.

  5. The job is converted successfully and its status is updated to JobStatus.Completed.

Using separate job types allows workflows to be created by defining each job type in Workers.xml and configuring a windows service for each job type. For more information on the Workers.xml configuration file and configuring the windows service for specific job types, refer to LEADTOOLS Job Processor Settings. For more information on creating worker assemblies, refer to Creating Job Processor Worker Assemblies.

References

Programming with the LEADTOOLS Distributed Computing (Job Processor) SDK LEADTOOLS Job Processor Settings Creating Job Processor Worker Assemblies Deploying LEADTOOLS Distributed Computing (JobProcessor) Applications

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