Description:
Windows 10 x64
Microsoft .NET Framework 4.6.2
Visual Studio 2015
MySql.Data 6.9.9
When MySqlConnectionStringBuilder.UseCompression = true is set, inserting a large random blob will throw the following exception:
Unhandled Exception: MySql.Data.MySqlClient.MySqlException: Unknown command
at MySql.Data.MySqlClient.MySqlStream.ReadPacket()
at MySql.Data.MySqlClient.NativeDriver.GetResult(Int32& affectedRow, Int64& insertedId)
at MySql.Data.MySqlClient.Driver.NextResult(Int32 statementId, Boolean force)
at MySql.Data.MySqlClient.MySqlDataReader.NextResult()
at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior)
at MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery()
at MySqlCompressBlob.Program.Main(String[] args) in Program.cs:line 33
I've pasted code to reproduce this at https://gist.github.com/bgrainger/ef06cf4d784a0df414f1a9406c74ccd8
In the example, creating a random blob of length 16519388 doesn't reproduce the problem, but making it one byte larger will.
Setting UseCompression=false will also work around the problem.
How to repeat:
Create a new C# console application with the source code at: https://gist.github.com/bgrainger/ef06cf4d784a0df414f1a9406c74ccd8
I've also reproduced the source below:
using System;
using MySql.Data.MySqlClient;
namespace MySqlCompressBlob
{
class Program
{
static void Main(string[] args)
{
var csb = new MySqlConnectionStringBuilder
{
Server = "localhost",
Database = "test",
UserID = "root",
Password = /* redacted */
UseCompression = true,
};
using (var connection = new MySqlConnection(csb.ConnectionString))
{
connection.Open();
using (var cmd = new MySqlCommand("drop table if exists test.blobs; create table test.blobs(data longblob)", connection))
cmd.ExecuteNonQuery();
var bytes = new byte[16519389]; // no exception with new byte[16519388]
var random = new Random(1);
random.NextBytes(bytes);
using (var cmd = new MySqlCommand("insert into test.blobs(data) values(@data);", connection))
{
cmd.Parameters.AddWithValue("data", bytes);
cmd.ExecuteNonQuery();
}
}
}
}
}
