Package org.apache.drill.exec.work.foreman.rm

Interface QueryQueue

All Known Implementing Classes:

DistributedQueryQueue, EmbeddedQueryQueue

public interface QueryQueue

Interface which defines a queue implementation for query queues. Implementations can queue locally, queue distributed, or do nothing at all.

A queue can report itself as enabled or disabled. When enabled, all queries must obtain a lease prior to starting execution. The lease must be released at the completion of execution.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static class	QueryQueue.QueryQueueException	Exception thrown for all non-timeout error conditions.
static interface	QueryQueue.QueueLease	The opaque lease returned once a query is admitted for execution.
static class	QueryQueue.QueueTimeoutException	Exception thrown if a query exceeds the configured wait time in the query queue.

Method Summary

Modifier and Type	Method	Description
void	close()
long	defaultQueryMemoryPerNode(double cost)	Return the amount of memory per node when creating a EXPLAIN query plan.
boolean	enabled()	Determine if the queue is enabled.
QueryQueue.QueueLease	enqueue(UserBitShared.QueryId queryId, double cost)	Queue a query.
long	minimumOperatorMemory()	Optional floor on the amount of memory assigned per operator.
void	setMemoryPerNode(long memoryPerNode)

Method Details

setMemoryPerNode

void setMemoryPerNode(long memoryPerNode)

defaultQueryMemoryPerNode

long defaultQueryMemoryPerNode(double cost)

Return the amount of memory per node when creating a EXPLAIN query plan. Plans to be executed should get the query memory from the lease, as the lease may adjust the default amount on a per-query basis. This means that the memory used to execute the query may differ from the amount shown in an EXPLAIN plan.

Returns:

assumed memory per node, in bytes, to use when creating an EXPLAIN plan

minimumOperatorMemory

long minimumOperatorMemory()

Optional floor on the amount of memory assigned per operator. This ensures that operators receive a certain amount, separate from any memory slicing. This can oversubscribe node memory if used incorrectly.

Returns:

minimum per-operator memory, in bytes

enabled

boolean enabled()

Determine if the queue is enabled.

Returns:

true if the query is enabled, false otherwise.

enqueue

QueryQueue.QueueLease enqueue(UserBitShared.QueryId queryId,
 double cost)
                       throws QueryQueue.QueueTimeoutException,
QueryQueue.QueryQueueException

Queue a query. The method returns only when the query is admitted for execution. As a result, the calling thread may block up to the configured wait time.

Parameters:

queryId - the query ID

cost - the cost of the query used for cost-based queueing

Returns:

the query lease which must be passed to #release(QueueLease) upon query completion

Throws:

QueryQueue.QueueTimeoutException - if the query times out waiting to be admitted.

QueryQueue.QueryQueueException - for any other error condition.

close

void close()