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Status

Current state:  Under Discussion  Discarded

Discussion thread: here [Change the link from the KIP proposal email archive to your own email thread] 

JIRA: here 

Please keep the discussion on the mailing list rather than commenting on the wiki (wiki discussions get unwieldy fast).

Motivation

Currently AdminClient supports describeTopics(Collection<String> topicNames) method API for describing topics and listTopics() API for listing topic name listingnames.
To describe all topics, users currently we need to use listTopics() to get all topic names and pass supply the name list to describeTopics. 

 In large clusters, the MetadataResponse can be large and sending multiple MetadataRequests can be inefficient.

Since "describe all topics" is a common operation, We propose to add describeTopics() method API to get all topic descriptions in single call.
This will be simple to use and avoids additional metadata requests.

Public Interfaces

API Changes

We will introduce new API methods to AdminClient to describe all topics. 

/**
 * Describe all topics in the cluster, with the default options.
 */
public DescribeAllTopicsResult describeTopics() {
    return describeTopics(new DescribeTopicsOptions());
}

/**
 * Describe all topics in the cluster.
 *
 * @return                  The DescribeAllTopicsResult.
 */
public abstract DescribeAllTopicsResult describeTopics(DescribeTopicsOptions options);

New result class "DescribeAllTopicsResult" will be added.

/**
 * The result of the {@link KafkaAdminClient#describeTopics()} call.
 */
public class DescribeAllTopicsResult {
    private final KafkaFuture<Collection<TopicDescription>> future;

    DescribeAllTopicsResult(KafkaFuture<Collection<TopicDescription>> future) {
        this.future = future;
    }

    public KafkaFuture<Collection<TopicDescription>> value() {
        return future;
    }
}

Proposed Changes

Describe the new thing you want to do in appropriate detail. This may be fairly extensive and have large subsections of its own. Or it may be a few sentences. Use judgement based on the scope of the change.

Compatibility, Deprecation, and Migration Plan

• What impact (if any) will there be on existing users?
• If we are changing behavior how will we phase out the older behavior?
• If we need special migration tools, describe them here.
• When will we remove the existing behavior?

Rejected Alternatives

...

• There won’t be any compatibility issues