[GitHub] [helix] narendly opened a new issue #509: Allow multiple readers for BucketDataAccessor

[GitBox <gi...@apache.org>]

narendly opened a new issue #509: Allow multiple readers for BucketDataAccessor
URL: https://github.com/apache/helix/issues/509
 
 
   Low Parallelism
   Currently, ZkBasedBucketDataAccessor uses a locking mechanism implemented using ZooKeeper's ephemeral nodes. This is similar to a mutex, and allows for one entity to either read/write. Since there could only be one ongoing operation, the users of this data accessor such as WAGED rebalancer suffers from low parallelism. More specifically, it is not possible to have verifiers read from the metadata written to ZK while some RW is happening for testing/verification purposes.
   
   Latency
   Overall latency of the rebalance pipeline (BestPossibleCalcStage) could be reduced if we could parallelize read and write operations. The current implementation, due to locking, has to linearize all read and write operations.
   
   Added Complexity from Locking
   Inevitably, there will be unexpected failures. When we use locks in a distributed manner, we need to account for all failure scenarios related to connection issues. This makes coding a little more difficult because of many try-catch statements.
   
   

----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
 
For queries about this service, please contact Infrastructure at:
users@infra.apache.org


With regards,
Apache Git Services

---------------------------------------------------------------------
To unsubscribe, e-mail: reviews-unsubscribe@helix.apache.org
For additional commands, e-mail: reviews-help@helix.apache.org