prestodb/presto · error · PrestoException

ICEBERG_TRANSACTION_CONFLICT_ERROR

ICEBERG_TRANSACTION_CONFLICT_ERROR

Error message

Not allowed to open write transactions on different tables

What it means

IcebergTransactionContext tracks at most one write transaction per coordinator transaction, keyed by table name. registerTransaction allows re-registering for the same table, but if transactions already exist for a different table it throws PrestoException(ICEBERG_TRANSACTION_CONFLICT_ERROR) because multi-table writes are not supported in one transaction.

Source

Thrown at presto-iceberg/src/main/java/com/facebook/presto/iceberg/transaction/IcebergTransactionContext.java:115

        return Optional.empty();
    }

    public Optional<Table> initiallyReadTable(SchemaTableName tableName)
    {
        if (initiallyReadTables.containsKey(tableName)) {
            return Optional.ofNullable(initiallyReadTables.get(tableName));
        }

        return Optional.empty();
    }

    public void registerTransaction(SchemaTableName tableName, Transaction transaction)
    {
        if (txByTable.isEmpty()) {
            txByTable.put(tableName, transaction);
        }
        else if (!txByTable.containsKey(tableName)) {
            throw new PrestoException(ICEBERG_TRANSACTION_CONFLICT_ERROR, "Not allowed to open write transactions on different tables");
        }
    }

    public Table getIcebergTable(SchemaTableName schemaTableName, Function<SchemaTableName, Table> rawIcebergTableLoader)
    {
        Table table = getTransactionTable(schemaTableName)
                .orElseGet(() -> initiallyReadTable(schemaTableName)
                        .orElseGet(() -> {
                            Table loadTable = rawIcebergTableLoader.apply(schemaTableName);
                            initiallyReadTables.computeIfAbsent(schemaTableName, ignored -> loadTable);
                            return loadTable;
                        }));
        return new TransactionalTable(schemaTableName, table, opsFromTable(table));
    }

    public void registerCallback(Runnable callback)
    {
        checkArgument(this.callbacksOnCommit.get() == null, "Cannot set callbacksOnCommit multiple times");

View on GitHub (pinned to 55bb57d202)

Solutions

Restructure the operation so each Presto transaction writes to a single Iceberg table (split into separate statements/transactions)
If a custom connector/plugin, ensure each table write acquires its own transaction context
Check for accidental aliasing where two different SchemaTableNames refer to what should be one table (case/catalog mismatch)

Example fix

// before
transactionContext.registerTransaction(tableA, tx);
transactionContext.registerTransaction(tableB, tx); // throws
// after
transactionContext.registerTransaction(tableA, tx);
// write to tableB in a separate transaction/statement

Defensive patterns

Strategy: try-catch

Validate before calling

if (transactionContext != null && !transactionContextIsEmptyOrContainsOnly(transactionContext, tableName)) {
    throw new IllegalStateException("Cannot write to multiple tables in one transaction: " + tableName);
}

Try / catch

try {
    transactionContext.registerTransaction(tableName, transaction);
} catch (PrestoException e) {
    if (e.getErrorCode().getName().equals("ICEBERG_TRANSACTION_CONFLICT_ERROR")) {
        throw new IllegalStateException(
            "Split the operation: only one Iceberg table may be written per transaction", e);
    }
    throw e;
}

Prevention

Design writes so each transaction targets exactly one Iceberg table
Avoid multi-table INSERT/MERGE patterns against Iceberg in a single statement/session
Verify SchemaTableName construction (catalog/schema/table casing) to avoid false conflicts

When it happens

Trigger: Calling registerTransaction(tableNameA, tx) and then registerTransaction(tableNameB, tx) within the same Presto transaction where tableNameB != tableNameA.

Common situations: A single INSERT/MERGE statement or session touching two Iceberg tables in write mode; a connector bug or plugin attempting cross-table writes in one transaction; queries combining writes to multiple catalogs/tables that map into the same transaction context.

Related errors

AI-assisted analysis of prestodb/presto@55bb57d202 (2026-09-04). Data as JSON: /api/errors/0e54b014181b1d44. Report an issue: GitHub.