tursodatabase/turso · error · InvalidOperationException

Cannot buffer a batch value of type {value.GetType().FullNam

Error message

Cannot buffer a batch value of type {value.GetType().FullName}.

What it means

ToBufferedValue converts an executed batch command's result value into a buffered RemoteResponseValue. Only a fixed set of types (e.g. integer, real, text, blob) is supported; any other runtime type reaches the default branch and throws InvalidOperationException naming the actual type.

Source

Thrown at bindings/dotnet/src/Turso.Data/TursoBatch.cs:292

                Type = "blob",
                Base64 = Convert.ToBase64String(bytes),
            },
            double number => new RemoteResponseValue
            {
                Type = "float",
                Value = JsonSerializer.SerializeToElement(number),
            },
            long number => new RemoteResponseValue
            {
                Type = "integer",
                Value = JsonSerializer.SerializeToElement(number),
            },
            string text => new RemoteResponseValue
            {
                Type = "text",
                Value = JsonSerializer.SerializeToElement(text),
            },
            _ => throw new InvalidOperationException(
                $"Cannot buffer a batch value of type {value.GetType().FullName}."),
        };
    }

    private TursoConnection ValidateBatch()
    {
        var connection = _connection ?? throw new InvalidOperationException("Connection must be set before executing a batch.");
        if (connection.State != ConnectionState.Open)
            throw new InvalidOperationException("Turso database is closed.");
        if (_transaction is { IsCompleted: true })
            throw new InvalidOperationException("The transaction associated with this batch has completed.");
        if (_transaction is not null && !ReferenceEquals(_transaction.Connection, connection))
            throw new InvalidOperationException("The transaction is not associated with the batch's connection.");
        if (_batchCommands.Count == 0)
            throw new InvalidOperationException("Batch must contain at least one command.");

        foreach (var command in _batchCommands.AsReadOnly())
        {

View on GitHub (pinned to 6c72522679)

Solutions

1. Cast or convert the offending column to a supported type (long, double, string, byte[]) in the SQL (e.g. CAST(col AS TEXT)).
2. Catch InvalidOperationException and fall back to executing that command outside the batch.
3. Report/upgrade the SDK if a standard SQLite type is being materialized as an unsupported CLR type.

Example fix

// before
SELECT myCustomValue() FROM t; // returns unsupported type
// after
SELECT CAST(myCustomValue() AS TEXT) FROM t;

foreach (DataColumn c in schemaTable.Columns)
    if (!new[] { typeof(long), typeof(double), typeof(string), typeof(byte[]) }.Contains(c.DataType))
        throw new InvalidOperationException($"Column {c.ColumnName} type {c.DataType} not batch-bufferable.");

try { results.AddRange(await batch.ExecuteBatchAsync(ct)); }
catch (InvalidOperationException ex) when (ex.Message.StartsWith("Cannot buffer a batch value"))
{ /* execute that command individually or CAST the column */ }

When it happens

Trigger: A batch command returns a column value whose CLR materialized type is outside the supported set — a custom scalar/aggregate extension return, an unexpected value type from the remote result, or a null-handling mismatch producing an unhandled type.

Common situations: Using extensions (e.g. vector, JSON) whose result values materialize as unsupported CLR types inside a batch on a sync database; upgrading Turso server so results return a new type the buffering code doesn't know.

Understand the failure class

Background: Type mismatch errors: IllegalArgumentException, TypeError and type guards across 150 open-source libraries — this error's family across 150 libraries.

Related errors

• Batch command must be a TursoBatchCommand.
• Parameter {value} is not a TursoParameter
• Connection must be a SqliteConnection.
• Transaction must be a SqliteTransaction.
• Turso batch execution requires a direct remote or embedded r

AI-assisted analysis of tursodatabase/turso@6c72522679 (2026-09-06). Data as JSON: /api/errors/a4c2c0115b02fd73. Report an issue: GitHub.