@InterfaceAudience.Public @InterfaceStability.Evolving public final class PleaseThrottleException extends NonRecoverableException implements HasFailedRpcException
Since all APIs of
AsyncKuduSession are asynchronous and non-blocking,
it's possible that the application would produce RPCs at a rate higher
than Kudu is able to handle. When this happens,
will typically do some buffering up to a certain point beyond which RPCs
will fail-fast with this exception, to prevent the application from
running itself out of memory.
This exception is expected to be handled by having the application
throttle or pause itself for a short period of time before retrying the
RPC that failed with this exception as well as before sending other RPCs.
The reason this exception inherits from
RecoverableException is that the usual course of action
when handling a
RecoverableException is to retry right away, which
would defeat the whole purpose of this exception. Here, we want the
application to retry after a reasonable delay as well as throttle
the pace of creation of new RPCs. What constitutes a "reasonable
delay" depends on the nature of RPCs and rate at which they're produced.
One effective strategy to handle this exception is to set a flag to true
when this exception is first emitted that causes the application to pause
or throttle its use of Kudu. Then you can retry the RPC that failed
(which is accessible through
getFailedRpc()) and add a callback to
it in order to unset the flag once the RPC completes successfully.
Note that low-throughput applications will typically rarely (if ever)
hit this exception, so they don't need complex throttling logic.
|Modifier and Type||Method and Description|
Returns a deferred one can wait on before retrying the failed RPC.
The RPC that was made to fail with this exception.
addSuppressed, fillInStackTrace, getCause, getLocalizedMessage, getMessage, getStackTrace, getSuppressed, initCause, printStackTrace, printStackTrace, printStackTrace, setStackTrace, toString
public Operation getFailedRpc()
public com.stumbleupon.async.Deferred getDeferred()
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