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Reference
Find details on the SPL language, toolkits, APIs, commands, and more.
Toolkits
A toolkit is a set of SPL artifacts, which are organized into a package. Toolkits make SPL or native functions and primitive or composite operators reusable across different applications.
Toolkits
Toolkit com.teracloud.streams.objectstorage 4.0.0
Protocol (client) selection

Welcome
Learn about the core capabilities of Teracloud® Streams, its architecture, and key concepts.
Installing
Use this information to install, upgrade, and uninstall the Teracloud® Streams product.
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Create a basic or an enterprise domain which is a single point for configuring and managing common resources, security, and instances.
Administering
Administer the product by using the Teracloud® Streams graphical user interface, APIs, or the streamtool command-line interface.
Developing
Develop stream applications with the Streams Processing Language (SPL), Java, and Python.
Troubleshooting
Resolve problems with Teracloud® Streams using the troubleshooting tools provided with the product as well as the resources offered by Teracloud Support.
Reference
Find details on the SPL language, toolkits, APIs, commands, and more.
- APIs
  Application programming interfaces (APIs) provide functions that simplify applications development.
- Job configuration overlays
  You can specify or change configuration parameters when you use the submitjob or updateoperators operations. The settings control submission constraints, host constraints and locations, and operator status. Parameters are captured and updated in the configuration JSON file. When you change the values in the job configuration overlay file, the changes override any previously set values.
- Commands
  Teracloud® Streams provides a number of commands you use to perform tasks.
- Operator model
  An operator model is an XML document that describes the basic properties of a primitive operator.
- Streams Processing Language (SPL)
  Streams Processing Language (SPL) is a distributed data flow composition language that is used in Teracloud® Streams. SPL has primitive types, program structures, and definitions that are tailored for streaming data.
- Toolkits
  A toolkit is a set of SPL artifacts, which are organized into a package. Toolkits make SPL or native functions and primitive or composite operators reusable across different applications.
  - Specialized toolkit requirements and restrictions
    Several of the specialized toolkits require RPMs that are not required by the Teracloud® Streams product. There are also toolkit restrictions on some platforms.
  - Toolkits
- SPLDOC markup
  You can use SPLDOC markup in the descriptions associated with the SPL artifacts in a toolkit. The spl-make-doc command generates HTML documentation from the marked up artifacts.
Glossary
Use this glossary to find terms and definitions for Teracloud® Streams.

Protocol (client) selection

The diagram represents represents two different clients which are utilized by the toolkit:

hadoop-aws (s3a protocol)
stocator (cos protocol)

You may easily select one of the two S3 clients by specifying appropriate protocol in the objectStorageURI parameter. The URI should be in cos://bucket/ or s3a://bucket/ format. Replace bucket with the name of the bucket you created. Concretely, when the s3a protocol is specified the toolkit uses hadoop-aws client. When cos protocol is specified the toolkit uses stocator client.

Note: The S3ObjectStorageSink, S3ObjectStorageSource and S3ObjectStorageScan operators have a protocol parameter for the client selection and a bucket parameter to specify the name of the bucket.

For ObjectStorageScan and ObjectStorageSource operator there is no big difference regarding the S3 client and you can select any of both clients. The ObjectStorageSink works different depending on the client selection.

The following are recommendations for client selection when writing objects in raw or parquet format:

Select s3a protocol when your application creates large objects one after another. Large objects are uploaded in multiple parts in parallel.
Select cos protocol when your application creates many objects within a narrow time frame. Multiple threads are uploading the entire object per thread in parallel.

When writing objects in partitioned parquet format both clients work similar and you may select one of the clients because of the different buffering mechanism:

hadoop-aws (s3a protocol): supports buffering in memory or disk (parameter s3aFastUploadBuffer). default:: memory buffer prior to upload
stocator (cos protocol): buffers on local disk prior to upload