apache/hadoop · error · IllegalArgumentException

Cache size is {}. Should be > 0

Error message

Cache size is {}. Should be > 0

What it means

Error "Cache size is {}. Should be > 0" thrown in apache/hadoop.

Source

Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/oncrpc/RpcCallCache.java:110

    public boolean equals(Object obj) {
      if (this == obj) {
        return true;
      }
      if (!(obj instanceof ClientRequest)) {
        return false;
      }
      ClientRequest other = (ClientRequest) obj;
      return clientId.equals(other.clientId) && (xid == other.xid);
    }
  }

  private final String program;

  private final Map<ClientRequest, CacheEntry> map;

  public RpcCallCache(final String program, final int maxEntries) {
    if (maxEntries <= 0) {
      throw new IllegalArgumentException("Cache size is " + maxEntries
          + ". Should be > 0");
    }
    this.program = program;
    map = new LinkedHashMap<ClientRequest, CacheEntry>() {
      private static final long serialVersionUID = 1L;

      @Override
      protected boolean removeEldestEntry(
          java.util.Map.Entry<ClientRequest, CacheEntry> eldest) {
        return RpcCallCache.this.size() > maxEntries;
      }
    };
  }

  /**
   * Return the program name.
   * @return RPC program name
   */

View on GitHub (pinned to 2add963021)

Solutions

1. Set the RPC duplicate-call cache size to a positive value in the configuration.
2. Remove or correct the configuration property that set the cache size to zero or a negative number.

When it happens

Trigger: Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/oncrpc/RpcCallCache.java:110 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/09da6e8757d54b52. Report an issue: GitHub.