prestodb/presto · error · IllegalArgumentException

Unsupported type for %s

Error message

Unsupported type for %s

What it means

getHashCode computes an identity hash for reference-counted cache keys from Block, Slice, array, or HashTables types; this throw is the terminal branch for any other key class passed to ReferenceCountMap, i.e. an unsupported key type.

Source

Thrown at presto-common/src/main/java/com/facebook/presto/common/array/ReferenceCountMap.java:97

        // The collision rate can be lower than 0.001% if there are 1000 different sizes.
        int extraIdentity;
        if (key == null) {
            extraIdentity = 0;
        }
        else if (key instanceof Block) {
            extraIdentity = (int) ((Block) key).getRetainedSizeInBytes();
        }
        else if (key instanceof Slice) {
            extraIdentity = (int) ((Slice) key).getRetainedSize();
        }
        else if (key.getClass().isArray()) {
            extraIdentity = getLength(key);
        }
        else if (key instanceof AbstractMapBlock.HashTables) {
            extraIdentity = (int) ((AbstractMapBlock.HashTables) key).getRetainedSizeInBytes();
        }
        else {
            throw new IllegalArgumentException(format("Unsupported type for %s", key));
        }
        return (((long) System.identityHashCode(key)) << Integer.SIZE) + extraIdentity;
    }
}

View on GitHub (pinned to 55bb57d202)

Solutions

1. Ensure only supported key kinds (Block, Slice, arrays) are placed in the reference-count map
2. Add a branch for the new key type if a new abstraction is introduced

When it happens

Trigger: Thrown at presto-common/src/main/java/com/facebook/presto/common/array/ReferenceCountMap.java:97 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of prestodb/presto@55bb57d202 (2026-09-04). Data as JSON: /api/errors/9b48071c5ecb6b88. Report an issue: GitHub.