Trino源码学习-内存管理

// io.trino.memory.QueryContext
public synchronized void initializeMemoryLimits(boolean resourceOverCommit, long maxUserMemory)
{
    checkArgument(maxUserMemory >= 0, "maxUserMemory must be >= 0, found: %s", maxUserMemory);
    if (resourceOverCommit) {
        // Allow the query to use the entire pool. This way the worker will kill the query, if it uses the entire local memory pool.
        // The coordinator will kill the query if the cluster runs out of memory.
        this.maxUserMemory = memoryPool.getMaxBytes();
    }
    else {
        this.maxUserMemory = maxUserMemory;
    }
    memoryLimitsInitialized = true;
}
private synchronized ListenableFuture<Void> updateUserMemory(TaskId taskId, String allocationTag, long delta)
{
    if (delta >= 0) {
        enforceUserMemoryLimit(memoryPool.getQueryMemoryReservation(queryId), delta, maxUserMemory);
        ListenableFuture<Void> future = memoryPool.reserve(taskId, allocationTag, delta);
        if (future.isDone()) {
            return NOT_BLOCKED;
        }

        return future;
    }
    memoryPool.free(taskId, allocationTag, -delta);
    return NOT_BLOCKED;
}

private void enforceUserMemoryLimit(long allocated, long delta, long maxMemory)
{
    if (allocated + delta > maxMemory) {
        throw exceededLocalUserMemoryLimit(succinctBytes(maxMemory), getAdditionalFailureInfo(allocated, delta));
    }
}

if (resourceOvercommit && outOfMemory) {
    // If a query has requested resource overcommit, only kill it if the cluster has run out of memory
    DataSize memory = succinctBytes(getQueryMemoryReservation(query));
    query.fail(new TrinoException(CLUSTER_OUT_OF_MEMORY,
            format("The cluster is out of memory and %s=true, so this query was killed. It was using %s of memory", RESOURCE_OVERCOMMIT, memory)));
    queryKilled = true;
}

if (!resourceOvercommit) {
    long userMemoryLimit = min(maxQueryMemory.toBytes(), getQueryMaxMemory(query.getSession()).toBytes());
    // 判断userMemory是否超出
    if (userMemoryReservation > userMemoryLimit) {
        query.fail(exceededGlobalUserLimit(succinctBytes(userMemoryLimit)));
        queryKilled = true;
    }
    // 判断totalMemory是否超出
    long totalMemoryLimit = min(maxQueryTotalMemory.toBytes(), getQueryMaxTotalMemory(query.getSession()).toBytes());
    if (totalMemoryReservation > totalMemoryLimit) {
        query.fail(exceededGlobalTotalLimit(succinctBytes(totalMemoryLimit)));
        queryKilled = true;
    }
}