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Dapper: micro-optimizations #31

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Merged
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Dec 1, 2015
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Dapper: micro-optimizations #31

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7 changes: 3 additions & 4 deletions src/Benchmarks/FortunesDapperMiddleware.cs
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Expand Up @@ -46,14 +46,13 @@ public async Task Invoke(HttpContext httpContext, HtmlEncoder htmlEncoder)

private static async Task<IEnumerable<Fortune>> LoadRows(string connectionString, DbProviderFactory dbProviderFactory)
{
var result = new List<Fortune>();
List<Fortune> result;

using (var db = dbProviderFactory.CreateConnection())
{
db.ConnectionString = connectionString;
await db.OpenAsync();

result.AddRange(await db.QueryAsync<Fortune>("SELECT [Id], [Message] FROM [Fortune]"));
// note: don't need to open connection if only doing one thing; let dapper do it
result = (await db.QueryAsync<Fortune>("SELECT [Id], [Message] FROM [Fortune]")).AsList();
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I'm assuming Dapper doesn't do any pre-sizing of the list, yes? I ask because it's a requirement of the test that it doesn't.

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If you mean "to match the expected data": then no, dapper doesn't do that, because it is consuming a raw IDataReader (DbDataReader on core-clr) API, and doesn't know the number of rows until it reaches the end. In this setup, it is essentially:

List<T> buffer = new List<T>();
while (await reader.ReadAsync(cancel).ConfigureAwait(false)) {
    buffer.Add(func(reader));
}
while (await reader.NextResultAsync(cancel).ConfigureAwait(false)) { }
return buffer;

(where func is a delegate that processes each row into the target data type)

Reference source is here; note that command.Buffered is true by default (most people screw up with things like concurrent commands, if handed back an open reader - so this defaults to the safest option of consuming the data before handing it back to the caller)

I ask because it's a requirement of the test that it doesn't.

Do you have a link to the test requirements? I would be happy to check them all.

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https://www.techempower.com/benchmarks/#section=code

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Thanks @benaadams ; I have reviewed the requirements; dapper does nothing that would violate Test 4 rule 5, if that is the concern.

}

result.Add(new Fortune { Message = "Additional fortune added at request time." });
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4 changes: 1 addition & 3 deletions src/Benchmarks/MultipleQueriesDapperMiddleware.cs
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Expand Up @@ -85,11 +85,9 @@ private static async Task<World[]> LoadRows(int count, string connectionString,

for (int i = 0; i < count; i++)
{
var world = await db.QueryAsync<World>(
result[i] = await db.QueryFirstOrDefaultAsync<World>(
"SELECT [Id], [RandomNumber] FROM [World] WHERE [Id] = @Id",
new { Id = _random.Next(1, 10001) });

result[i] = world.First();
}

db.Close();
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9 changes: 2 additions & 7 deletions src/Benchmarks/SingleQueryDapperMiddleware.cs
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Expand Up @@ -61,15 +61,10 @@ private static async Task<World> LoadRow(string connectionString, DbProviderFact
using (var db = dbProviderFactory.CreateConnection())
{
db.ConnectionString = connectionString;
await db.OpenAsync();

var world = await db.QueryAsync<World>(
// note: don't need to open connection if only doing one thing; let dapper do it
return await db.QueryFirstOrDefaultAsync<World>(
"SELECT [Id], [RandomNumber] FROM [World] WHERE [Id] = @Id",
new { Id = _random.Next(1, 10001) });

db.Close();

return world.First();
}
}
}
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