ExecuteStatementAsync() not returning number of rows affected

[nikkhn]

ExecuteStatementAsync() not returning number of rows affected

[MikeAmputer]

This library uses the HTTP interface of the ClickHouse server. According to the official documentation:

For successful requests that do not return a data table, an empty response body is returned.

So, there are no options to retrieve the amount of affected rows, while the ADO.NET contract of DbCommand requires an int value to be returned.

In some cases, you can use the ClickHouseCommand.QueryStats attribute to access written_rows metrics provided by the X-ClickHouse-Summary response header. This is particularly useful for INSERT statements, but note that it is set to 0 for TRUNCATE statements.

[MikeAmputer]

To be honest, I’m not entirely sure if the ExecuteNonQueryAsync implementation will ever return a non-zero value:

using var reader = new ExtendedBinaryReader(await response.Content.ReadAsStreamAsync().ConfigureAwait(false));
return reader.PeekChar() != -1 ? reader.Read7BitEncodedInt() : 0;

All the tests still pass (checked for 23.6) if I simplify this to return 0; (or any other value) =)

[nikkhn]

hm ok i misunderstood the client code then. I was looking at this Connection Extensions method and assumed it was using this method as a wrapper over the DbCommand class. (im a bit new to .NET so trying to get my head around things)

[MikeAmputer]

Correct. The extension method you mentioned calls command.ExecuteNonQueryAsync(), which is the method I was referring to. To access WrittenRows, you'll need to create a command manually:

using var command = connection.CreateCommand();
command.CommandText = sql;
await command.ExecuteNonQueryAsync();
var writtenRows = command.QueryStats.WrittenRows;

[nikkhn]

AH i see, ok! thank you @MikeAmputer :)