I would like to initiate the voting process for the "KIP-4 Delete Topics Schema changes". This is not a vote for all of KIP-4, but specifically for the delete topics changes. I have included the exact changes below for clarity: > > Delete Topics Request (KAFKA-2946 > <https://issues.apache.org/jira/browse/KAFKA-2946>) > > DeleteTopics Request (Version: 0) => [topics] timeout > topics => STRING > timeout => INT32 > > DeleteTopicsRequest is a batch request to initiate topic deletion. > > Request semantics: > > 1. Must be sent to the controller broker > 2. If there are multiple instructions for the same topic in one > request the extra request will be ingnored > - This is because the list of topics is modeled server side as a set > - Multiple deletes results in the same end goal, so handling this > error for the user should be okay > 3. When requesting to delete a topic that does not exist, a an > InvalidTopic error will be returned for that topic. > 4. When requesting to delete a topic that is already marked for > deletion, the request will wait up to the timeout until the delete is > "complete" and return as usual. > - This is to avoid errors due to concurrent delete requests. The > end result is the same, the topic is deleted. > 5. The principal must be authorized to the "Delete" Operation on the > "Topic" resource to delete the topic. > - Unauthorized requests will receive a TopicAuthorizationException > if they are authorized to the "Describe" Operation on the "Topic" > resource > - Otherwise they will receive an InvalidTopicException as if the > topic does not exist. > 6. Setting a timeout > 0 will allow the request to block until the > delete is "complete" on the controller node. > - Complete means the local topic metadata cache no longer contains > the topic > - The topic metadata is updated when the controller sends out > update metadata requests to the brokers > - If a timeout error occurs, the topic could still be deleted > successfully at a later time. Its up to the client to query for the > state > at that point. > 7. Setting a timeout <= 0 will validate arguments and trigger the > delete topics and return immediately. > - This is essentially the fully asynchronous mode we have in the > Zookeeper tools today. > - The error code in the response will either contain an argument > validation exception or a timeout exception. If you receive a timeout > exception, because you asked for 0 timeout, you can assume the message > was > valid and the topic deletion was triggered. > 8. The request is not transactional. > 1. If an error occurs on one topic, the others could still be > deleted. > 2. Errors are reported independently. > > QA: > > - Why is DeleteTopicsRequest a batch request? > - Scenarios where tools or admins want to delete many topics should > be able to with fewer requests > - Example: Removing all cluster topics > - What happens if some topics error immediately? Will it > return immediately? > - The request will block until all topics have either been deleted, > errors, or the timeout has been hit > - There is no "short circuiting" where 1 error stops the other > topics from being deleted > - Why have a timeout at all? Deletes could take a while? > - True some deletes may take a while or never finish, however some > admin tools may want extended blocking regardless. > - If you don't want any blocking setting a timeout of 0 works. > - Future changes may make deletes much faster. See the Follow Up > Changes > > <https://cwiki.apache.org/confluence/display/KAFKA/KIP-4+-+Command+line+and+centralized+administrative+operations#KIP-4-Commandlineandcentralizedadministrativeoperations-follow-up-changes> > section > above. > - Why implement "partial blocking" instead of fully async or fully > consistent? > - See Cluster Consistent Blocking > > <https://cwiki.apache.org/confluence/display/KAFKA/KIP-4+-+Command+line+and+centralized+administrative+operations#KIP-4-Commandlineandcentralizedadministrativeoperations-cluster-consistent-blocking> > below > - Why require the request to go to the controller? > - The controller is responsible for the cluster metadata and its > propagation > - See Request Forwarding > > <https://cwiki.apache.org/confluence/display/KAFKA/KIP-4+-+Command+line+and+centralized+administrative+operations#KIP-4-Commandlineandcentralizedadministrativeoperations-request> > below > > Delete Topics Response > > DeleteTopics Response (Version: 0) => [topic_error_codes] > topic_error_codes => topic error_code > topic => STRING > error_code => INT16 > > DeleteTopicsResponse contains a map between topic and topic creation > result error code (see New Protocol Errors > <https://cwiki.apache.org/confluence/display/KAFKA/KIP-4+-+Command+line+and+centralized+administrative+operations#KIP-4-Commandlineandcentralizedadministrativeoperations-NewProtocolErrors> > ). > > Response semantics: > > 1. When a request hits the timeout, the topics that are not "complete" > will have the TimeoutException error code. > - The topics that did complete successfully with have no error. > > The KIP is available here for reference (linked to the Create Topics schema section): *https://cwiki.apache.org/confluence/display/KAFKA/KIP-4+-+Command+line+and+centralized+administrative+operations#KIP-4-Commandlineandcentralizedadministrativeoperations-DeleteTopicsRequest(KAFKA-2946) <https://cwiki.apache.org/confluence/display/KAFKA/KIP-4+-+Command+line+and+centralized+administrative+operations#KIP-4-Commandlineandcentralizedadministrativeoperations-DeleteTopicsRequest(KAFKA-2946)>*
A sample patch is on github: https://github.com/granthenke/kafka/tree/delete-wire-new Note: This branch and patch is based on the CreateTopic request/response PR. I will open a PR once that patch is complete. Here is a link to the past discussion on the mailing list: *http://search-hadoop.com/m/uyzND1fokOBn6uNd2&subj=+DISCUSS+KIP+4+Delete+Topic+Schema <http://search-hadoop.com/m/uyzND1fokOBn6uNd2&subj=+DISCUSS+KIP+4+Delete+Topic+Schema>* Thank you, Grant -- Grant Henke Software Engineer | Cloudera gr...@cloudera.com | twitter.com/gchenke | linkedin.com/in/granthenke
