prestodb/presto · error · OrcCorruptionException

Unexpected row group count stripe in at offset %s

Error message

Unexpected row group count stripe in at offset %s

What it means

Write-validation error: the number of row groups found for a stripe at the given offset differs from the expected count. The on-disk row-group index diverges from the writer's record — an internal consistency check firing during post-write validation, usually indicating corruption or a writer bug.

Source

Thrown at presto-orc/src/main/java/com/facebook/presto/orc/OrcWriteValidation.java:285

        if (expected == null) {
            throw new OrcCorruptionException(orcDataSourceId, "Unexpected stripe at offset %s", stripeOffset);
        }
        validateColumnStatisticsEquivalent(orcDataSourceId, "Stripe at " + stripeOffset, actual, expected.getColumnStatistics());
    }

    public void validateRowGroupStatistics(OrcDataSourceId orcDataSourceId, long stripeOffset, Map<StreamId, List<RowGroupIndex>> actualRowGroupStatistics)
            throws OrcCorruptionException
    {
        requireNonNull(actualRowGroupStatistics, "actualRowGroupStatistics is null");
        List<RowGroupStatistics> expectedRowGroupStatistics = rowGroupStatistics.get(stripeOffset);
        if (expectedRowGroupStatistics == null) {
            throw new OrcCorruptionException(orcDataSourceId, "Missing row group column statistics for stripe at offset %s", stripeOffset);
        }

        int rowGroupCount = expectedRowGroupStatistics.size();
        for (Entry<StreamId, List<RowGroupIndex>> entry : actualRowGroupStatistics.entrySet()) {
            if (entry.getValue().size() != rowGroupCount) {
                throw new OrcCorruptionException(orcDataSourceId, "Unexpected row group count stripe in at offset %s", stripeOffset);
            }
        }

        for (int rowGroupIndex = 0; rowGroupIndex < expectedRowGroupStatistics.size(); rowGroupIndex++) {
            RowGroupStatistics expectedRowGroup = expectedRowGroupStatistics.get(rowGroupIndex);
            if (expectedRowGroup.getValidationMode() != HASHED) {
                Map<Integer, ColumnStatistics> expectedStatistics = expectedRowGroup.getColumnStatistics();
                Map<Integer, ColumnStatistics> actualStatistics = aggregateRowGroupStatisticsFromRowIndex(orcDataSourceId, actualRowGroupStatistics, stripeOffset, rowGroupIndex);

                // remove empty row group stats for empty flat maps
                expectedStatistics = adjustRowGroupStatisticsForFlatMaps(orcDataSourceId, stripeOffset, expectedStatistics);
                actualStatistics = adjustRowGroupStatisticsForFlatMaps(orcDataSourceId, stripeOffset, actualStatistics);

                Set<Integer> actualColumns = actualStatistics.keySet();
                Set<Integer> expectedColumns = expectedStatistics.keySet();

                if (!expectedColumns.equals(actualColumns)) {
                    throw new OrcCorruptionException(orcDataSourceId, "Unexpected column in row group %s in stripe at offset %s", rowGroupIndex, stripeOffset);

View on GitHub (pinned to 55bb57d202)

Solutions

1. Reproduce with orc writer validation to confirm
2. Report as a Presto ORC bug if consistent
3. Rewrite the affected file(s)

When it happens

Trigger: Thrown at presto-orc/src/main/java/com/facebook/presto/orc/OrcWriteValidation.java:285 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/eeaef8534797ac93. Report an issue: GitHub.