Configure Max Batch Size in Java

This page describes how to set up max batch size limitation for resource batch methods in Java.

Contents

• Define Max Batch Size
• Batch Size Validation
• Backward Compatibility Rules

For Rest.li resources, we provide infrastructure support that enables users to define the @MaxBatchSize annotation on the batch methods and provides the opt-in batch size validation based on the defined @MaxBatchSize.

Define Max Batch Size

Users can use @MaxBatchSize annotation to define the max batch size on Rest.li batch methods.

@MaxBatchSize(value = 100, validate = true)
public BatchResult<Long, Photo> batchGet(Set<Long> ids)
{
 // Logic here...
}

The @MaxBatchSize annotation contains two elements: value and validate. value is an integer specifying the max batch size. validate is a boolean flag for validating the request batch size, which is an optional field. If the validate is not provided, the value of validate is false by default, which means there is no request batch size validation.

List of methods which can use @MaxBatchSize annotation: BATCH_GET, BATCH_UPDATE, BATCH_PARTIAL_UPDATE, BATCH_DELETE, BATCH_CREATE and BATCH_FINDER.

Note: for BATCH_FINDER, the batch size means the number of criteria, not the collection size for each criteria.

Documenting max batch size information in the IDL.

Once the @MaxBatchSize annotation is defined, the batch size information will be exposed in the IDL(restspec.json), for example:

{ "name" : "someResource",
   ...
  "collection" : {
	"methods" : [ {
      "method" : "batch_get",
      "maxBatchSize" : {
        "value" : 100,
        "validate" : true
      }
    }, {
      "method" : "batch_update",
      "maxBatchSize" : {
        "value" : 100,
        "validate" : false
      }
    } ],
    ...
  }
  ...
}

Batch Size validation

If validate in the @MaxBatchSize is specified as true, on the Rest.li server, when it processes the request, it will check the request that has @MaxBatchSize annotation, and compare the batch size of each request with the defined max batch size of such method. If the actual batch size is larger than the defined max batch size, it will fail the request with http status 400.

Example of enabling batch size validation:

@RestMethod.BatchGet
@MaxBatchSize(value = 100, validate = true)
public Map<Long, Greeting> batchGet(Set<Long> ids)
{
 // Logic here...
}

Batch size validation is an opt-in feafture. If validate in the @MaxBatchSize is specified as false or validate field is not provided, the @MaxBatchSize is used to provide batch size information, the Rest.li server will not take any action based on the value of max batch size.

Examples of disabling batch size validation:

@RestMethod.BatchDelete
@MaxBatchSize(value = 50, validate = false)
public BatchUpdateResult<Long, Greeting> batchDelete(BatchDeleteRequest<Long, Greeting> deleteRequest)
{
 // Logic here...
}

@RestMethod.BatchPartialUpdate
@MaxBatchSize(value = 100)
public BatchUpdateResult<Long, Greeting> batchUpdate(BatchPatchRequest<Long, Greeting> entityUpdates)
{
 // Logic here...
}

Backward Compatibility Rules

Making changes to the max batch size information in a resource’s IDL has an impact on the compatibility checker.

The following changes are considered backward compatible:

• Adding a @MaxBatchSize annotation with validation disabled.
• Removing an existing @MaxBatchSize annotation.
• Increasing the value of max batch size.
• Decreasing the value of max batch size when validation is disabled.
• Updating validate value from true to false.

The following changes are considered backward incompatible:

• Adding a @MaxBatchSize annotation with validation enabled.
• Updating validate value from false to true.
• Decreasing the value of max batch size when validation is enabled.