Examples with TraversingQueryContextVisitor com.facebook.presto.memory.TraversingQueryContextVisitor used on opensource projects

Example 1 with TraversingQueryContextVisitor

use of com.facebook.presto.memory.TraversingQueryContextVisitor in project presto by prestodb.

the class MemoryRevokingSchedulerUtils method getMemoryAlreadyBeingRevoked.

public static long getMemoryAlreadyBeingRevoked(Collection<TaskContext> taskContexts, long targetRevokingLimit) {
    TraversingQueryContextVisitor<Void, Long> visitor = new TraversingQueryContextVisitor<Void, Long>() {

        @Override
        public Long visitOperatorContext(OperatorContext operatorContext, Void context) {
            if (operatorContext.isMemoryRevokingRequested()) {
                return operatorContext.getReservedRevocableBytes();
            }
            return 0L;
        }

        @Override
        public Long mergeResults(List<Long> childrenResults) {
            return childrenResults.stream().mapToLong(i -> i).sum();
        }
    };
    long currentRevoking = 0;
    for (TaskContext taskContext : taskContexts) {
        currentRevoking += taskContext.accept(visitor, null);
        if (currentRevoking > targetRevokingLimit) {
            // Return early, target value exceeded and revoking will not occur
            return currentRevoking;
        }
    }
    return currentRevoking;
}