type Plugin interface {
	Name() string
	Initialize(*DB) error
}

type ParamsFilter interface {
	ParamsFilter(ctx context.Context, sql string, params ...interface{}) (string, []interface{})
}

// ConnPool db conns pool interface
type ConnPool interface {
	PrepareContext(ctx context.Context, query string) (*sql.Stmt, error)
	ExecContext(ctx context.Context, query string, args ...interface{}) (sql.Result, error)

		ctx := r.Context()
		select {
		case pool <- struct{}{}:
			defer func() { <-pool }()
			globalHTTPStats.addRequestsInQueue(-1)
			if contextCanceled(ctx) {
				w.WriteHeader(499)
				return
			}
			f.ServeHTTP(w, r)
		case <-r.Context().Done():
			globalHTTPStats.addRequestsInQueue(-1)
			// When the client disconnects before getting the S3 handler

    // pool ID but a thread ID of 2.
    Thread thread2 = threadFactory.newThread(monitoredRunnable);
    checkThreadPoolName(thread2, 2);
    assertEquals(
        thread.getName().substring(0, thread.getName().lastIndexOf('-')),
        thread2.getName().substring(0, thread.getName().lastIndexOf('-')));

    // Building again should give us a different pool ID.

          "expr": "minio_cluster_health_status{job=~\"$scrape_jobs\"}",
          "fullMetaSearch": false,
          "includeNullMetadata": true,
          "interval": "",
          "legendFormat": "Pool: {{pool}} Set: {{set}}",
          "range": true,
          "refId": "A",
          "useBackend": false
        }
      ],
      "title": "Cluster Health Status",
      "type": "stat"
    },
    {

    val id: Int,
  ) : RoutePlanner.Plan {
    var planningThrowable: Throwable? = null
    var canceled = false
    var connectState = ConnectState.READY
    val connection =
      factory.newConnection(
        pool = pool,
        route = factory.newRoute(address),
        idleAtNanos = defaultConnectionIdleAtNanos,
      )
    var retry: FakePlan? = null
    var retryTaken = false
    var yieldBeforePlanReturns = false

 1. It uses the URL and configured OkHttpClient to create an **address**. This address specifies how we'll connect to the webserver.
 2. It attempts to retrieve a connection with that address from the **connection pool**.
 3. If it doesn't find a connection in the pool, it selects a **route** to attempt. This usually means making a DNS request to get the server's IP addresses. It then selects a TLS version and proxy server if necessary.

    connections.add(connection)
//    connection.queueEvent { connectionListener.connectEnd(connection) }
    scheduleCloser()
  }

  /**
   * Notify this pool that [connection] has become idle. Returns true if the connection has been
   * removed from the pool and should be closed.
   */
  fun connectionBecameIdle(connection: RealConnection): Boolean {
    connection.lock.assertHeld()

    int tasksPerThread = 10;
    int nTasks = nThreads * tasksPerThread;
    ExecutorService pool = Executors.newFixedThreadPool(nThreads);
    ImmutableList<String> keys = ImmutableList.of("a", "b", "c");
    try {
      List<Future<int[]>> futures = newArrayListWithExpectedSize(nTasks);
      for (int i = 0; i < nTasks; i++) {
        futures.add(pool.submit(new MutateTask(multiset, keys)));
      }

      int[] deltas = new int[3];

> **NOTE:** **Each pool you add must have the same erasure coding parity configuration as the original pool, so the same data redundancy SLA is maintained.**

	queue       chan *queueItem // output from workers in order
	err         error           // global error state, only touched by Reader.Read
	bufferPool  sync.Pool       // pool of []byte objects for input
	kvDstPool   sync.Pool       // pool of []jstream.KV used for output
	close       chan struct{}   // used for shutting down the splitter before end of stream
	readerWg    sync.WaitGroup  // used to keep track of async reader.
}