apache/hadoop · error · InvalidRequestException

Limit is negative.

Error message

Limit is negative.

What it means

Client-side validation in CachePoolInfo.validate(): a cache pool limit that is set (non-null) and negative is rejected with InvalidRequestException before/while the request reaches the NameNode. The limit is the aggregate byte cap for a cache pool; negative values have no meaning.

Source

Thrown at hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/protocol/CachePoolInfo.java:222

  @Override
  public int hashCode() {
    return new HashCodeBuilder().
        append(poolName).
        append(ownerName).
        append(groupName).
        append(mode).
        append(limit).
        append(defaultReplication).
        append(maxRelativeExpiryMs).
        hashCode();
  }

  public static void validate(CachePoolInfo info) throws IOException {
    if (info == null) {
      throw new InvalidRequestException("CachePoolInfo is null");
    }
    if ((info.getLimit() != null) && (info.getLimit() < 0)) {
      throw new InvalidRequestException("Limit is negative.");
    }
    if ((info.getDefaultReplication() != null)
            && (info.getDefaultReplication() < 0)) {
      throw new InvalidRequestException("Default Replication is negative");
    }

    if (info.getMaxRelativeExpiryMs() != null) {
      long maxRelativeExpiryMs = info.getMaxRelativeExpiryMs();
      if (maxRelativeExpiryMs < 0l) {
        throw new InvalidRequestException("Max relative expiry is negative.");
      }
      if (maxRelativeExpiryMs > Expiration.MAX_RELATIVE_EXPIRY_MS) {
        throw new InvalidRequestException("Max relative expiry is too big.");
      }
    }
    validateName(info.poolName);
  }

View on GitHub (pinned to 2add963021)

Solutions

1. Do not set a negative limit; to express 'no limit' leave the limit unset (null) or set CachePoolInfo.limitUnlimited.
2. Clamp computed limits: long limit = Math.max(0, computedLimit).
3. Validate CachePoolInfo before submitting if the value comes from external input.

Example fix

// before
CachePoolInfo info = new CachePoolInfo("pool").setLimit(requestedLimit); // requestedLimit = -1

// after
CachePoolInfo info = new CachePoolInfo("pool");
if (requestedLimit != null && requestedLimit >= 0) {
  info.setLimit(requestedLimit);
}

if (info.getLimit() != null && info.getLimit() < 0) {
  throw new IllegalArgumentException("limit must be >= 0, got " + info.getLimit());
}
dfs.addCachePool(info);

try { dfs.addCachePool(info); }
catch (InvalidRequestException e) { /* surface field error to caller/config */ }

When it happens

Trigger: addCachePool or modifyCachePool with CachePoolInfo.setLimit(-1) (or any negative long), including arithmetic that computes a limit from free space and underflows below zero.

Common situations: Scripts computing pool limits from cluster metrics where subtraction yields a negative number; porting code from a system where -1 meant 'unlimited'.

Related errors

• {key} = {v} <= 0
• Requested replication factor of {replication}{err} for {src}
• dfs.datanode.parallel.volumes.load.threads.num = {} < 1
• Invalid values: dfs.bytes-per-checksum (={}) must divide cel
• Invalid checksum type: userOpt=${userOpt}, default=${default

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/686a1761e531ff52. Report an issue: GitHub.