Janardhan Hungund created HBASE-28934:
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Summary: The HFile Reader creation should not be blocked due to
waits for cache initialisation.
Key: HBASE-28934
URL: https://issues.apache.org/jira/browse/HBASE-28934
Project: HBase
Issue Type: Bug
Components: BucketCache
Reporter: Janardhan Hungund
Assignee: Janardhan Hungund
The bucket cache is initialised from the persistent cache file during server
restarts. This cache initialisation is asynchronous to the server restarts. The
server restart completes after spawning a thread to initialise the cache.
When the subsequent HFile readers are created, the current implementation is
such that the constructor of the hfile (HFilePreadReader) waits until the cache
is initialised. Due to this wait, all requests to these regions are blocked due
to cache initialisation. Even the errors related to "regions are not online" is
returned to the client.
The correct way to handle this is that, the constructors of HFile readers
should not wait for cache initialisation. Only the prefetch threads should wait
for the cache initialisation.
Subsequently, any client requests should be served by accessing the data main
storage (cloud storage) if the cache is not yet initialised.
Thanks,
Janardhan
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