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Multiplexing: ConnectorTypeMapping isn't thread-safe (since preview5)

See original GitHub issue

TypeMapping seems very broken since preview 5

     System.InvalidOperationException: Operations that change non-concurrent collections must have exclusive access. A concurrent update was performed on this collection and corrupted its state. The collection's state is no longer correct.
         at System.Collections.Generic.Dictionary`2.FindValue(TKey key)
         at System.Collections.Generic.Dictionary`2.TryGetValue(TKey key, TValue& value)
         at Npgsql.TypeMapping.ConnectorTypeMapper.Bind(NpgsqlTypeHandler handler, PostgresType pgType, Nullable`1 npgsqlDbType, Type[] clrTypes)
         at Npgsql.TypeMapping.ConnectorTypeMapper.Bind(NpgsqlTypeMapping mapping, PostgresType pgType)
         at Npgsql.TypeMapping.ConnectorTypeMapper.BindArray(NpgsqlTypeMapping elementMapping)
         at Npgsql.TypeMapping.ConnectorTypeMapper.GetByClrType(Type type)
         at Npgsql.NpgsqlParameter.ResolveHandler(ConnectorTypeMapper typeMapper)
         at Npgsql.NpgsqlCommand.ValidateParameters(ConnectorTypeMapper typeMapper)
         at Npgsql.NpgsqlCommand.ExecuteReader(CommandBehavior behavior, Boolean async, CancellationToken cancellationToken)
         at Npgsql.NpgsqlCommand.ExecuteReader(CommandBehavior behavior, Boolean async, CancellationToken cancellationToken)
         at Npgsql.NpgsqlCommand.ExecuteDbDataReaderAsync(CommandBehavior behavior, CancellationToken cancellationToken)

System.IndexOutOfRangeException: Index was outside the bounds of the array.
         at System.Collections.Generic.Dictionary`2.TryInsert(TKey key, TValue value, InsertionBehavior behavior)
         at Npgsql.TypeMapping.ConnectorTypeMapper.Bind(NpgsqlTypeHandler handler, PostgresType pgType, Nullable`1 npgsqlDbType, Type[] clrTypes)
         at Npgsql.TypeMapping.ConnectorTypeMapper.Bind(NpgsqlTypeMapping mapping, PostgresType pgType)
         at Npgsql.TypeMapping.ConnectorTypeMapper.BindArray(NpgsqlTypeMapping elementMapping)
         at Npgsql.TypeMapping.ConnectorTypeMapper.GetByClrType(Type type)
         at Npgsql.NpgsqlParameter.ResolveHandler(ConnectorTypeMapper typeMapper)
         at Npgsql.NpgsqlCommand.ValidateParameters(ConnectorTypeMapper typeMapper)
         at Npgsql.NpgsqlCommand.ExecuteReader(CommandBehavior behavior, Boolean async, CancellationToken cancellationToken)
         at Npgsql.NpgsqlCommand.ExecuteReader(CommandBehavior behavior, Boolean async, CancellationToken cancellationToken)
         at Npgsql.NpgsqlCommand.ExecuteDbDataReaderAsync(CommandBehavior behavior, CancellationToken cancellationToken)

and other fun manifestations of concurrent inits. preview4 is ok so it must be one of the AOT preparation PRs that caused this.

Issue Analytics

State:
Created 2 years ago
Comments:6 (6 by maintainers)

Top GitHub Comments

1reaction

vonzshikcommented, Jul 6, 2021

Yeah, I found the problem - MultiplexingConnectorPool.MultiplexingTypeMapper is used by every command on the same pool, and since ConnectorTypeMapper isn’t thread safe…

0reactions

rojicommented, Jul 15, 2021

As discussed offline, we should try to avoid having another TypeMapper just for multiplexing - just using ConcurrentDictionary in ConnectorTypeMapper may be good enough (also need to pay attention to racing bindings)

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