protected virtual async Task ConsumeCharsAsync(DataStressReader reader, int i, CancellationToken token, Random rnd)
{
char[] buffer = new char[255];
if (rnd.NextBool())
{
// Read with GetChars
reader.GetChars(i, rnd.Next(20), buffer, rnd.Next(20), rnd.Next(200));
}
else if (reader.GetProviderSpecificFieldType(i) == typeof(SqlXml))
{
// SqlClient only: Xml is read by XmlReader
DataStressXmlReader xmlReader = reader.GetXmlReader(i);
xmlReader.Read();
}
else
{
// Read with TextReader
DataStressTextReader textReader = reader.GetTextReader(i);
if (rnd.NextBool())
{
textReader.Peek();
}
await textReader.ReadSyncOrAsync(buffer, rnd.Next(20), rnd.Next(200), rnd);
if (rnd.NextBool())
{
textReader.Peek();
}
}
}
/// <summary>
/// Utility function to consume a single row of a reader in a random fashion after Read/ReadAsync has been invoked.
/// </summary>
protected virtual async Task ConsumeRowAsync(DataStressReader reader, bool sequentialAccess, CancellationToken token, Random rnd)
{
for (int i = 0; i < reader.FieldCount; i++)
{
if (rnd.Next(10) == 0)
{
break; // stop reading from this row
}
if (rnd.Next(2) == 0)
{
continue; // skip this field
}
bool hasBeenRead = false;
// If the field is not null, we can optionally use streaming API
if ((!await reader.IsDBNullSyncOrAsync(i, token, rnd)) && (rnd.NextBool()))
{
Type t = reader.GetFieldType(i);
if (t == typeof(byte[]))
{
await ConsumeBytesAsync(reader, i, token, rnd);
hasBeenRead = true;
}
else if (t == typeof(string))
{
await ConsumeCharsAsync(reader, i, token, rnd);
hasBeenRead = true;
}
}
// If the field has not yet been read, or if it is non-sequential then we can re-read it
if ((!hasBeenRead) || (!sequentialAccess))
{
if (!await reader.IsDBNullSyncOrAsync(i, token, rnd))
{
// Field value is not null, we can use new GetFieldValue<T> methods
await reader.GetValueSyncOrAsync(i, token, rnd);
}
else
{
// Field value is null, we have to use old GetValue method
reader.GetValue(i);
}
}
// Do IsDBNull check again with 50% probability
if (rnd.NextBool())
{
await reader.IsDBNullSyncOrAsync(i, token, rnd);
}
}
}
/// <summary>
/// Utility function to consume a reader in a random fashion
/// </summary>
protected virtual async Task ConsumeReaderAsync(DataStressReader reader, bool sequentialAccess, CancellationToken token, Random rnd)
{
// Close 1/10 of readers while they are reading
Task closeTask = null;
if (AllowReaderCloseDuringReadAsync() && rnd.NextBool(0.1))
{
// Begin closing now on another thread
closeTask = reader.CloseAsync();
}
try
{
do
{
while (await reader.ReadSyncOrAsync(token, rnd))
{
// Optionally stop reading the current result set
if (rnd.NextBool(0.1))
{
break;
}
// Read the current row
await ConsumeRowAsync(reader, sequentialAccess, token, rnd);
}
// Executing NextResult only 50% of the time
if (rnd.NextBool())
{
break;
}
} while (await reader.NextResultSyncOrAsync(token, rnd));
}
catch (Exception e)
{
if (closeTask != null && IsReaderClosedException(e))
{
// Catch reader closed exception
}
else
{
throw;
}
}
finally
{
if (closeTask != null)
{
AsyncUtils.WaitAndUnwrapException(closeTask);
}
}
}
protected virtual async Task ConsumeBytesAsync(DataStressReader reader, int i, CancellationToken token, Random rnd)
{
byte[] buffer = new byte[255];
if (rnd.NextBool())
{
// We can optionally use GetBytes
reader.GetBytes(i, rnd.Next(20), buffer, rnd.Next(20), rnd.Next(200));
}
else if (reader.GetName(i) != "timestamp_FLD")
{
// Timestamp appears to be binary, but cannot be read by Stream
DataStressStream stream = reader.GetStream(i);
await stream.ReadSyncOrAsync(buffer, rnd.Next(20), rnd.Next(200), token, rnd);
}
else
{
// It is timestamp column, so read it later with GetValueSyncOrAsync
await reader.GetValueSyncOrAsync(i, token, rnd);
}
}
public DataStressXmlReader(XmlReader xmlReader, DataStressReader reader)
{
_xmlReader = xmlReader;
_reader = reader;
}
public DataStressTextReader(TextReader textReader, DataStressReader reader)
{
_textReader = textReader;
_reader = reader;
}
public DataStressStream(Stream stream, DataStressReader reader)
{
_stream = stream;
_reader = reader;
}
protected async virtual Task CommandExecuteAsync(Random rnd, DbCommand com, bool query)
{
CancellationTokenSource cts = null;
// Cancel 1/10 commands
Task cancelTask = null;
bool cancelCommand = rnd.NextBool(0.1);
if (cancelCommand)
{
if (rnd.NextBool())
{
// Use DbCommand.Cancel
cancelTask = Task.Run(() => CommandCancel(com));
}
else
{
// Use CancellationTokenSource
if (cts == null)
{
cts = new CancellationTokenSource();
}
cancelTask = Task.Run(() => cts.Cancel());
}
}
// Get the CancellationToken
CancellationToken token = (cts != null) ? cts.Token : CancellationToken.None;
DataStressReader reader = null;
try
{
if (query)
{
CommandBehavior commandBehavior = CommandBehavior.Default;
if (rnd.NextBool(0.5))
{
commandBehavior |= CommandBehavior.SequentialAccess;
}
if (rnd.NextBool(0.25))
{
commandBehavior |= CommandBehavior.KeyInfo;
}
if (rnd.NextBool(0.1))
{
commandBehavior |= CommandBehavior.SchemaOnly;
}
// Get the reader
reader = new DataStressReader(await com.ExecuteReaderSyncOrAsync(commandBehavior, token, rnd));
// Consume the reader's data
await ConsumeReaderAsync(reader, commandBehavior.HasFlag(CommandBehavior.SequentialAccess), token, rnd);
}
else
{
await com.ExecuteNonQuerySyncOrAsync(token, rnd);
}
}
catch (Exception e)
{
if (cancelCommand && IsCommandCancelledException(e))
{
// Catch command canceled exception
}
else
{
throw;
}
}
finally
{
if (cancelTask != null)
{
AsyncUtils.WaitAndUnwrapException(cancelTask);
}
if (reader != null && ShouldCloseDataReader())
{
reader.Close();
}
}
}
