apache/cassandra · error · InvalidRequestException

Batch too large

Error message

Batch too large

What it means

verifyBatchSize enforces the batch_size_fail_threshold guardrail: when the serialized size of a batch exceeds the fail threshold, the batch is rejected with InvalidRequestException 'Batch too large' after tracing and logging the violation. Large batches cause coordinator memory pressure and are a known anti-pattern.

Solutions

1. Split the batch into smaller batches or individual statements (async/parallel writes)
2. Raise batch_size_fail_threshold_in_kb in cassandra.yaml only if you truly understand the memory implications
3. Use a proper bulk-load path (COPY, sstableloader, or the bulk writer) instead of CQL batches
4. Reduce row/cell size being inserted per batch

Example fix

// before
// one BEGIN BATCH with 5000 INSERTs
// after
for (List<BoundStatement> chunk : partition(boundStatements, 100)) {
    execute(BatchStatement.unlogged(chunk));
}

long approxSize = statements.stream().mapToLong(Statement::getSize).sum();
if (approxSize > batchSizeFailThresholdBytes) splitIntoSmallerBatches();

catch (InvalidRequestException e) { if (e.getMessage().equals("Batch too large")) { chunkAndRetryInSmallerBatches(); } else throw e; }

When it happens

Trigger: Executing (via executeWithoutConditions) a batch whose total serialized mutation size exceeds batch_size_fail_threshold_in_kb (default 50 KB, or 10000x warn threshold config); typically huge multi-partition unlogged batches or bulk-load attempts through CQL batches.

Common situations: Bulk imports via giant batches; time-series backfills inserting thousands of rows per batch; misconfigured thresholds after upgrading (threshold behavior changed across Cassandra versions).

Understand the failure class

Background: payload too large / request exceeds maximum size: why libraries cap bytes and how to fix oversize payloads — this error's family across 50 libraries.

Related errors

• Batch with conditions cannot span multiple partitions
• Batch with conditions cannot span multiple tables
• Cannot alter gc_grace_seconds of a materialized view to 0…
• Cannot include a counter statement in a logged batch
• Cannot include a virtual table statement in a logged batch

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/6d5aa33ad0180cae. Report an issue: GitHub.

Appendix: source

Thrown at src/java/org/apache/cassandra/cql3/statements/BatchStatement.java:452

        if (size > warnThreshold)
        {
            Set<String> tableNames = new HashSet<>();
            for (IMutation mutation : mutations)
            {
                for (PartitionUpdate update : mutation.getPartitionUpdates())
                    tableNames.add(update.metadata().toString());
            }

            long failThreshold = DatabaseDescriptor.getBatchSizeFailThreshold();

            String format = "Batch for {} is of size {}, exceeding specified threshold of {} by {}.{}";
            if (size > failThreshold)
            {
                Tracing.trace(format, tableNames, FBUtilities.prettyPrintMemory(size), FBUtilities.prettyPrintMemory(failThreshold),
                              FBUtilities.prettyPrintMemory(size - failThreshold), " (see batch_size_fail_threshold)");
                logger.error(format, tableNames, FBUtilities.prettyPrintMemory(size), FBUtilities.prettyPrintMemory(failThreshold),
                             FBUtilities.prettyPrintMemory(size - failThreshold), " (see batch_size_fail_threshold)");
                throw new InvalidRequestException("Batch too large");
            }
            else if (logger.isWarnEnabled())
            {
                logger.warn(format, tableNames, FBUtilities.prettyPrintMemory(size), FBUtilities.prettyPrintMemory(warnThreshold),
                            FBUtilities.prettyPrintMemory(size - warnThreshold), "");
            }
            ClientWarn.instance.warn(MessageFormatter.arrayFormat(format, new Object[] {tableNames, size, warnThreshold, size - warnThreshold, ""}).getMessage());
        }
    }

    private void verifyBatchType(Collection<? extends IMutation> mutations)
    {
        if (!isLogged() && mutations.size() > 1)
        {
            Set<DecoratedKey> keySet = new HashSet<>();
            Set<String> tableNames = new HashSet<>();

            for (IMutation mutation : mutations)

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