[jira] [Commented] (HBASE-24389) Introduce a new master rpc service to locate meta region through root region

["Michael Stack (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-24389?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17118214#comment-17118214 ] 

Michael Stack commented on HBASE-24389:
---------------------------------------

Mind doing a bit of a write up on what this is doing. On quick review this adds a new 'Service' that does the below API:

{code}
enum RegionLocateType {
  REGION_LOCATE_TYPE_BEFORE =1;
  REGION_LOCATE_TYPE_CURRENT = 2;
  REGION_LOCATE_TYPE_AFTER = 3;
}

message LocateMetaRegionRequest {
  required bytes row = 1;
  required RegionLocateType locateType = 2;
}

message LocateMetaRegionResponse {
  repeated RegionLocation meta_locations = 1;
}

message GetAllMetaRegionLocationsRequest {
  required bool exclude_offlined_split_parents = 1;
}

message GetAllMetaRegionLocationsResponse {
  repeated RegionLocation meta_locations = 1;
}

/**
 * Implements the RPCs needed by clients to look up the location of meta region.
 */
service ClientLocateMetaRegionService {
  rpc LocateMetaRegion(LocateMetaRegionRequest)
    returns(LocateMetaRegionResponse);

  rpc GetAllMetaRegionLocations(GetAllMetaRegionLocationsRequest)
    returns(GetAllMetaRegionLocationsResponse);
}
{code}

Master is hard-coded to mediate the lookup? Doesn't seem to go via Registry? (Didn't spend much time looking) Or a client config. would allow providing different impls?

This is new API that is not how we usually do the Read of location. Do we want to implement RegionLocation on this? https://hbase.apache.org/apidocs/org/apache/hadoop/hbase/client/RegionLocator.html

Would client impl do get all regions or would it use the one-at-a time? Does this API imply anything about meta table size?  Would we be able to have a table of 10k Regions?

Thanks



> Introduce a new master rpc service to locate meta region through root region
> ----------------------------------------------------------------------------
>
>                 Key: HBASE-24389
>                 URL: https://issues.apache.org/jira/browse/HBASE-24389
>             Project: HBase
>          Issue Type: Sub-task
>          Components: master, meta
>            Reporter: Duo Zhang
>            Assignee: Duo Zhang
>            Priority: Major
>
> And also reimlement the client logic to use the new api to locate meta region. In general, this will remove the assumption at client side that there is only one meta region. 



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