apache/hadoop · error · IllegalStateException

Wait failed for get(%d)

Error message

Wait failed for get(%d)

What it means

CachingBlockManager.get loops acquire + getInternal until the block reaches a terminal DONE state, retrying under a Retryer (10 attempts, max delay scaling with pool size: bufferPoolSize*120*1000 ms). If the block never completes — usually because the remote store keeps failing the fetch — it gives up with IllegalStateException("Wait failed for get(N)"), after logging "waiting to get block" warnings that include the manager state.

Source

Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/impl/prefetch/CachingBlockManager.java:173

      if (closed) {
        throw new IOException("this stream is already closed");
      }

      data = bufferPool.acquire(blockNumber);
      done = getInternal(data);

      if (retryer.updateStatus()) {
        LOG.warn("waiting to get block: {}", blockNumber);
        LOG.info("state = {}", this.toString());
      }
    }
    while (!done && retryer.continueRetry());

    if (done) {
      return data;
    } else {
      String message = String.format("Wait failed for get(%d)", blockNumber);
      throw new IllegalStateException(message);
    }
  }

  private boolean getInternal(BufferData data) throws IOException {
    Validate.checkNotNull(data, "data");

    // Opportunistic check without locking.
    if (data.stateEqualsOneOf(
        BufferData.State.PREFETCHING,
        BufferData.State.CACHING,
        BufferData.State.DONE)) {
      return false;
    }

    synchronized (data) {
      // Reconfirm state after locking.
      if (data.stateEqualsOneOf(
          BufferData.State.PREFETCHING,

View on GitHub (pinned to 2add963021)

Solutions

1. Read the earlier log lines: the first underlying store exception (auth, 403/404, throttle) is the root cause — fix that first
2. Inspect the "waiting to get block" / "state =" warnings to see which blocks stay PREFETCHING/CACHING and why
3. Raise the retry budget/delay or reduce read parallelism so attempts fit inside the window
4. Verify data-source health and prefetch settings (block size, pool size) against the file size being read

catch IllegalStateException("Wait failed for get"); check logs for the underlying store failure and fix it, then reopen the stream at the last known position and retry the read once with reduced parallelism.

When it happens

Trigger: The underlying data source (object store / http backend) returning repeated errors for the block's byte range; a prefetch task dying without marking the block DONE; every attempt exceeding the retry window on a very slow link.

Common situations: Object-store credential/permission failures surfacing mid-file; throttling (429/503) during large parallel prefetches; prefetch configuration (block size, pool size) mismatched to the file and read pattern; network brownouts stretching every fetch past the budget.

Related errors

• Retry " + retry + " times to read still exception: " + error
• No such file or directory '{}'
• Filesystem does not support symlinks!
• Wait failed for acquire(%d)
• this stream is already closed

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/b9b676402ae10215. Report an issue: GitHub.