public void TestDataReaderReadException()
{
// Setup two data readers from shards
var mockReader1 = new MockSqlDataReader("Reader1");
var mockReader2 = new MockSqlDataReader("Reader2");
bool movedOnToNextReader = false;
int invokeCount = 1;
Func <MockSqlDataReader, Task <bool> > ExecuteOnReadAsync = (r) =>
{
return(Task.Run <bool>(() =>
{
// First reader throws an exception when Read
if (r.Name == "Reader1")
{
if (invokeCount == 2)
{
throw new InvalidOperationException();
}
}
else
{
movedOnToNextReader = true;
}
return true;
}));
};
Action <MockSqlDataReader> ExecuteOnGetColumn = (r) =>
{
if (r.Name == "Reader1")
{
throw new InvalidOperationException();
}
};
mockReader1.ExecuteOnReadAsync = ExecuteOnReadAsync;
mockReader1.ExecuteOnGetColumn = ExecuteOnGetColumn;
mockReader2.ExecuteOnReadAsync = ExecuteOnReadAsync;
var labeledDataReaders = new LabeledDbDataReader[2];
labeledDataReaders[0] = new LabeledDbDataReader(mockReader1, new ShardLocation("test", "Shard1"),
new MockSqlCommand()
{
Connection = new MockSqlConnection("", () => { })
});
labeledDataReaders[1] = new LabeledDbDataReader(mockReader2, new ShardLocation("test", "Shard2"),
new MockSqlCommand()
{
Connection = new MockSqlConnection("", () => { })
});
// Create the MultiShardDataReader
var mockMultiShardCmd = MultiShardCommand.Create(null, "test");
var multiShardDataReader = new MultiShardDataReader(mockMultiShardCmd, labeledDataReaders,
MultiShardExecutionPolicy.PartialResults, false);
// Validate that if an exception is thrown when reading a column,
// it is propagated back to the user
try
{
multiShardDataReader.Read();
invokeCount++;
multiShardDataReader.GetInt32(0);
}
catch (Exception ex)
{
Assert.IsTrue(ex is InvalidOperationException, "Expected InvalidOperationException!");
}
// Validate that we didn't automatically move on to the next reader when we
// hit an exception whilst reading the column and that
// an exception from a second Read() call is stored and the reader is closed
multiShardDataReader.Read();
Assert.AreEqual(multiShardDataReader.MultiShardExceptions.Count, 1, "Expected exception to be recorded");
Assert.IsTrue(mockReader1.IsClosed, "Expected reader to be closed!");
// Validate we immediately moved on to the next reader
multiShardDataReader.Read();
Assert.IsTrue(movedOnToNextReader, "Should've moved on to next reader");
}
public void TestAddDataReaderWithNullSchema()
{
// Creates a MultiShardDataReader and verifies that the right exception is thrown
Func <LabeledDbDataReader[], bool> createMultiShardReader = (readers) =>
{
bool hitNullSchemaException = false;
try
{
var mockMultiShardCmd = MultiShardCommand.Create(null, "test");
var multiShardDataReader = new MultiShardDataReader(mockMultiShardCmd, readers,
MultiShardExecutionPolicy.PartialResults, false, readers.Length);
}
catch (MultiShardDataReaderInternalException ex)
{
hitNullSchemaException = ex.Message.Contains("null schema");
}
return(hitNullSchemaException);
};
var labeledDataReaders = new LabeledDbDataReader[10];
// Create a few mock readers. All with a null schema
for (int i = 0; i < labeledDataReaders.Length; i++)
{
var mockReader = new MockSqlDataReader(string.Format("Reader{0}", i), null /* Null schema */);
labeledDataReaders[i] = new LabeledDbDataReader(mockReader,
new ShardLocation("test", string.Format("Shard{0}", i)), new MockSqlCommand()
{
Connection = new MockSqlConnection("", () => { })
});
}
// Case #1
bool hitException = createMultiShardReader(labeledDataReaders);
Assert.IsFalse(hitException, "Unexpected exception! All readers have a null schema.");
// Case #2
for (int i = 0; i < labeledDataReaders.Length; i++)
{
MockSqlDataReader mockReader = (MockSqlDataReader)labeledDataReaders[i].DbDataReader;
mockReader.Open();
if (i > labeledDataReaders.Length / 2)
{
mockReader.DataTable = new DataTable();
}
}
hitException = createMultiShardReader(labeledDataReaders);
Assert.IsTrue(hitException, "Exception not hit! Second half of readers don't have a null schema!");
// Case #3
for (int i = 0; i < labeledDataReaders.Length; i++)
{
MockSqlDataReader mockReader = (MockSqlDataReader)labeledDataReaders[i].DbDataReader;
mockReader.Open();
if (i < labeledDataReaders.Length / 2)
{
mockReader.DataTable = new DataTable();
}
else
{
mockReader.DataTable = null;
}
}
hitException = createMultiShardReader(labeledDataReaders);
Assert.IsTrue(hitException, "Exception not hit! First half of readers don't have a null schema!");
}
public void TestShardCommandRetryConnectionReopen()
{
var retryPolicy = new RetryPolicy(4, TimeSpan.FromMilliseconds(100), TimeSpan.FromSeconds(10), TimeSpan.FromMilliseconds(100));
var shardConnections = new List <Tuple <ShardLocation, DbConnection> >();
// Callback to execute when the MockCommand is invoked
Func <CancellationToken, MockSqlCommand, DbDataReader> ExecuteReaderFunc = null;
// Number of times each command has been retried
var commandRetryCounts = new int[10];
// Create ten mocked connections,
// a few of them will throw an exception on Open
// and the rest will throw an exception on command execution upto 2 retries
// At the end, all commands should complete successfully.
for (int i = 0; i < 10; i++)
{
string database = string.Format("{0}", i);
int j = i;
int retryCount = 0;
Action executeOnOpen = () =>
{
if (j < 5)
{
if (retryCount < 3)
{
retryCount++;
throw new TimeoutException();
}
}
};
var mockCon = new MockSqlConnection(database, executeOnOpen);
shardConnections.Add(new Tuple <ShardLocation, DbConnection>(new ShardLocation("Shard", database), mockCon));
}
ExecuteReaderFunc = (t, r) =>
{
int index = Int32.Parse(((MockSqlConnection)(r.Connection)).ConnectionString);
if (r.Connection.State == ConnectionState.Closed)
{
throw new InvalidOperationException("Command shouldn't be executed on a closed connection!");
}
if (index > 5 && commandRetryCounts[index] < 3)
{
commandRetryCounts[index]++;
r.RetryCount++;
r.Connection.Close();
throw new TimeoutException();
}
else
{
var mockRdr = new MockSqlDataReader();
mockRdr.ExecuteOnReadAsync = (rdr) =>
{
return(Task.Run <bool>(() =>
{
bool isClosed = rdr.IsClosed;
rdr.Close();
return !isClosed;
}));
};
return(mockRdr);
}
};
var mockCmd = new MockSqlCommand();
mockCmd.ExecuteReaderFunc = ExecuteReaderFunc;
mockCmd.CommandText = "select 1";
using (var conn = new MultiShardConnection(shardConnections))
{
using (var cmd = MultiShardCommand.Create(conn, mockCmd, 300))
{
cmd.RetryPolicy = retryPolicy;
cmd.ExecutionPolicy = MultiShardExecutionPolicy.PartialResults;
using (var reader = cmd.ExecuteReaderAsync().Result)
{
// Validate that we successfully received a reader
// from each one of the shards
int readerCount = 0;
while (reader.Read())
{
readerCount++;
}
Assert.AreEqual(10, readerCount, "Expected 10 readers!");
}
}
}
}
