prestodb/presto · error · IllegalArgumentException

Offset is not monotonically ascending. offsets[%s]=%s, offse

Error message

Offset is not monotonically ascending. offsets[%s]=%s, offsets[%s]=%s

What it means

Structural invariant check when building an ArrayBlock: the offsets array must be monotonically non-decreasing; a decreasing pair means corrupted or mis-computed offsets and the block would read negative-length arrays.

Source

Thrown at presto-common/src/main/java/com/facebook/presto/common/block/ArrayBlock.java:57

    private final long retainedSizeInBytes;

    private volatile long sizeInBytes;
    private volatile long logicalSizeInBytes;

    /**
     * Create an array block directly from columnar nulls, values, and offsets into the values.
     * A null array must have no entries.
     */
    public static Block fromElementBlock(int positionCount, Optional<boolean[]> valueIsNullOptional, int[] arrayOffset, Block values)
    {
        boolean[] valueIsNull = valueIsNullOptional.orElse(null);
        validateConstructorArguments(0, positionCount, valueIsNull, arrayOffset, values);
        // for performance reasons per element checks are only performed on the public construction
        for (int i = 0; i < positionCount; i++) {
            int offset = arrayOffset[i];
            int length = arrayOffset[i + 1] - offset;
            if (length < 0) {
                throw new IllegalArgumentException(format("Offset is not monotonically ascending. offsets[%s]=%s, offsets[%s]=%s", i, arrayOffset[i], i + 1, arrayOffset[i + 1]));
            }
            if (valueIsNull != null && valueIsNull[i] && length != 0) {
                throw new IllegalArgumentException("A null array must have zero entries");
            }
        }
        return new ArrayBlock(0, positionCount, valueIsNull, arrayOffset, values);
    }

    /**
     * Create an array block directly without per element validations.
     */
    static ArrayBlock createArrayBlockInternal(int arrayOffset, int positionCount, @Nullable boolean[] valueIsNull, int[] offsets, Block values)
    {
        validateConstructorArguments(arrayOffset, positionCount, valueIsNull, offsets, values);
        return new ArrayBlock(arrayOffset, positionCount, valueIsNull, offsets, values);
    }

    private static void validateConstructorArguments(int arrayOffset, int positionCount, @Nullable boolean[] valueIsNull, int[] offsets, Block values)

View on GitHub (pinned to 55bb57d202)

Solutions

1. Fix the offset computation in the producer (block builder / deserializer) to be non-decreasing
2. Check for int overflow when accumulating element counts

When it happens

Trigger: Thrown at presto-common/src/main/java/com/facebook/presto/common/block/ArrayBlock.java:57 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/2e58abfa18ccb04f. Report an issue: GitHub.