使用 C# 从 GridFS 下载大文件会导致排序超出内存限制错误

Question

我正在使用以下代码从 GridFS 下载文件。

var stream = await this.gridFsBucket.OpenDownloadStreamAsync(new ObjectId(fileId));

我收到以下错误：

MongoDB.Driver.MongoCommandException: Command find failed: Executor error during find command :: caused by :: Sort exceeded memory limit of 33554432 bytes, but did not opt in to external sorting..
   at MongoDB.Driver.Core.WireProtocol.CommandUsingCommandMessageWireProtocol`1.ProcessResponse(ConnectionId connectionId, CommandMessage responseMessage)
   at MongoDB.Driver.Core.WireProtocol.CommandUsingCommandMessageWireProtocol`1.ExecuteAsync(IConnection connection, CancellationToken cancellationToken)
   at MongoDB.Driver.Core.Servers.Server.ServerChannel.ExecuteProtocolAsync[TResult](IWireProtocol`1 protocol, ICoreSession session, CancellationToken cancellationToken)
   at MongoDB.Driver.Core.Operations.RetryableReadOperationExecutor.ExecuteAsync[TResult](IRetryableReadOperation`1 operation, RetryableReadContext context, CancellationToken cancellationToken)
   at MongoDB.Driver.Core.Operations.ReadCommandOperation`1.ExecuteAsync(RetryableReadContext context, CancellationToken cancellationToken)
   at MongoDB.Driver.Core.Operations.FindCommandOperation`1.ExecuteAsync(RetryableReadContext context, CancellationToken cancellationToken)
   at MongoDB.Driver.Core.Operations.FindOperation`1.ExecuteAsync(RetryableReadContext context, CancellationToken cancellationToken)
   at MongoDB.Driver.Core.Operations.FindOperation`1.ExecuteAsync(IReadBinding binding, CancellationToken cancellationToken)
   at MongoDB.Driver.GridFS.GridFSForwardOnlyDownloadStream`1.GetFirstBatchAsync(CancellationToken cancellationToken)
   at MongoDB.Driver.GridFS.GridFSForwardOnlyDownloadStream`1.GetSegmentAsync(CancellationToken cancellationToken)
   at MongoDB.Driver.GridFS.GridFSForwardOnlyDownloadStream`1.ReadAsync(Byte[] buffer, Int32 offset, Int32 count, CancellationToken cancellationToken)
   at Microsoft.AspNetCore.Http.StreamCopyOperationInternal.CopyToAsync(Stream source, Stream destination, Nullable`1 count, Int32 bufferSize, CancellationToken cancel)
   at Microsoft.AspNetCore.Mvc.Infrastructure.FileResultExecutorBase.WriteFileAsync(HttpContext context, Stream fileStream, RangeItemHeaderValue range, Int64 rangeLength)
   at Microsoft.AspNetCore.Mvc.Infrastructure.FileStreamResultExecutor.ExecuteAsync(ActionContext context, FileStreamResult result)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeResultAsync>g__Logged|21_0(ResourceInvoker invoker, IActionResult result)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeNextResultFilterAsync>g__Awaited|29_0[TFilter,TFilterAsync](ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResultExecutedContextSealed context)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.ResultNext[TFilter,TFilterAsync](State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeResultFilters>g__Awaited|27_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeFilterPipelineAsync>g__Awaited|19_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Logged|17_1(ResourceInvoker invoker)
   at Microsoft.AspNetCore.Routing.EndpointMiddleware.<Invoke>g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)
   at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
   at Swashbuckle.AspNetCore.SwaggerUI.SwaggerUIMiddleware.Invoke(HttpContext httpContext)
   at Swashbuckle.AspNetCore.Swagger.SwaggerMiddleware.Invoke(HttpContext httpContext, ISwaggerProvider swaggerProvider)
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

我试图找到一种方法为 GridFS 启用 allowDiskUse 为真，但找不到。

Answer 1

您可能缺少驱动程序应该自动创建的索引。

• 确保您使用的是最新版本的驱动程序。
• 将另一个文件上传到同一个 GridFS 存储桶。之后您可以立即删除该文件。
• 手动检查索引是否存在。请参阅“索引”下的 here 了解应该存在的内容。

Answer 2

我在使用 DownloadAsBytes 时遇到了这个错误。

通过删除数据库然后让 GridF 再次创建数据库来解决该错误。