MySqlException on bool filter with inner join

Hi everyone, we are facing a problem when sending a query that includes a filter in the where clause with a boolean. The error surfaces when it’s in combination with an inner join and another table.

We got 3 tables, AAfiliado (280k rows), AAfiliadoGrupoFamiliar (130k rows) and GEmpresa (65k rows)

AAfiliado has FK to AAfiliadoGrupoFamiliar. GEmpresa has an Unique index CUIT.

CUIT and CuitEmpleador are long type, not null, (bigint(11) on db). Activo is boolean, not null, tinyint(1)

The code: (‘estado’ is boolean type)

This is the linq query:

(from item in _context.AAfiliado where item.Activo == estado 
  join empresa in _context.GEmpresa on item.AGrupoFamiliar.CuitEmpleador equals empresa.Cuit into empresas 
  from empresa in empresas.DefaultIfEmpty() select item).Count();

This outputs the following query:

SELECT COUNT(*) FROM a_afiliado AS a
INNER JOIN a_grupo_familiar AS a0 ON a.a_grupo_familiarId = a0.id
LEFT JOIN g_empresa AS g ON a0.cuit_empleador = g.CUIT 
WHERE (a.activo = @__estado_0)

This throws an exception:

Exception: MySqlConnector.MySqlException (0x80004005): Internal error: oscar hash join failed
   at MySqlConnector.Core.ResultSet.g_ScanRowAsyncAwaited|9_0(ResultSet resultSet, Task`1 payloadTask, Row row, CancellationToken token) in //src/MySqlConnector/Core/ResultSet.cs:line 240
   at MySqlConnector.Core.ResultSet.ReadAsync(IOBehavior ioBehavior, CancellationToken cancellationToken) in //src/MySqlConnector/Core/ResultSet.cs:line 211
   at MySqlConnector.Core.ResultSet.Read() in //src/MySqlConnector/Core/ResultSet.cs:line 187
   at Microsoft.EntityFrameworkCore.Query.Internal.SingleQueryingEnumerable`1.Enumerator.MoveNext()
   at System.Linq.Enumerable.TryGetSingle[TSource](IEnumerable`1 source, Boolean& found)
   at lambda_method31667.lambda_method31667(Closure , QueryContext )

What’s really strange is that if we put a hardcoded value in the linq query:

(from item in _context.AAfiliado where (item.Activo == true && estado == true) || (item.Activo == false && estado == false)
  join empresa in _context.GEmpresa on item.AGrupoFamiliar.CuitEmpleador equals empresa.Cuit into empresas 
  from empresa in empresas.DefaultIfEmpty() select item).Count();

This outputs the following query:

SELECT COUNT(*) FROM a_afiliado AS a 
INNER JOIN a_grupo_familiar AS a0 ON a.a_grupo_familiarId = a0.id 
LEFT JOIN g_empresa AS g ON a0.cuit_empleador = g.CUIT 
WHERE a.activo

That work fine. What could be the cause of this?

Update:

MySQL version: 5.7.12 (Aurora 2.10.2) Pomelo.EntityFrameworkCore.MySql version: 6.0.0 Microsoft.AspNetCore.App version: net6.0

[Raiquen]

Updated MySql to 8, with Aurora, these queries and Pomelo 6.0.1 work fines, without Pipelining = False.

Let’s take some time to update our system.

Thanks for the help!

[mguinness]

Just to reiterate, I think the issue lies with Aurora. Have you tried against a local MySQL?