/// <summary>
/// Generates a subset of the rows from the result set
/// </summary>
/// <param name="startRow">The starting row of the results</param>
/// <param name="rowCount">How many rows to retrieve</param>
/// <returns>A subset of results</returns>
public Task <ResultSetSubset> GetSubset(long startRow, int rowCount)
{
// Sanity check to make sure that results read has started
if (!hasStartedRead)
{
throw new InvalidOperationException(SR.QueryServiceResultSetNotRead);
}
// Sanity check to make sure that the row and the row count are within bounds
if (startRow < 0 || startRow >= RowCount)
{
throw new ArgumentOutOfRangeException(nameof(startRow), SR.QueryServiceResultSetStartRowOutOfRange);
}
if (rowCount <= 0)
{
throw new ArgumentOutOfRangeException(nameof(rowCount), SR.QueryServiceResultSetRowCountOutOfRange);
}
return(Task.Factory.StartNew(() =>
{
DbCellValue[][] rows;
using (IFileStreamReader fileStreamReader = fileStreamFactory.GetReader(outputFileName))
{
// If result set is 'for xml' or 'for json',
// Concatenate all the rows together into one row
if (isSingleColumnXmlJsonResultSet)
{
// Iterate over all the rows and process them into a list of string builders
// ReSharper disable once AccessToDisposedClosure The lambda is used immediately in string.Join call
IEnumerable <string> rowValues = fileOffsets.Select(rowOffset => fileStreamReader.ReadRow(rowOffset, 0, Columns)[0].DisplayValue);
string singleString = string.Join(string.Empty, rowValues);
DbCellValue cellValue = new DbCellValue
{
DisplayValue = singleString,
IsNull = false,
RawObject = singleString,
RowId = 0
};
rows = new[] { new[] { cellValue } };
}
else
{
// Figure out which rows we need to read back
IEnumerable <long> rowOffsets = fileOffsets.LongSkip(startRow).Take(rowCount);
// Iterate over the rows we need and process them into output
// ReSharper disable once AccessToDisposedClosure The lambda is used immediately in .ToArray call
rows = rowOffsets.Select((offset, id) => fileStreamReader.ReadRow(offset, id, Columns).ToArray()).ToArray();
}
}
// Retrieve the subset of the results as per the request
return new ResultSetSubset
{
Rows = rows,
RowCount = rows.Length
};
}));
}
/// <summary>
/// Generates a subset of the rows from the result set
/// </summary>
/// <param name="startRow">The starting row of the results</param>
/// <param name="rowCount">How many rows to retrieve</param>
/// <returns>A subset of results</returns>
public Task <ResultSetSubset> GetSubset(int startRow, int rowCount)
{
// Sanity check to make sure that the results have been read beforehand
if (!hasBeenRead)
{
throw new InvalidOperationException(SR.QueryServiceResultSetNotRead);
}
// Sanity check to make sure that the row and the row count are within bounds
if (startRow < 0 || startRow >= RowCount)
{
throw new ArgumentOutOfRangeException(nameof(startRow), SR.QueryServiceResultSetStartRowOutOfRange);
}
if (rowCount <= 0)
{
throw new ArgumentOutOfRangeException(nameof(rowCount), SR.QueryServiceResultSetRowCountOutOfRange);
}
return(Task.Factory.StartNew(() =>
{
string[][] rows;
using (IFileStreamReader fileStreamReader = fileStreamFactory.GetReader(outputFileName))
{
// If result set is 'for xml' or 'for json',
// Concatenate all the rows together into one row
if (isSingleColumnXmlJsonResultSet)
{
// Iterate over all the rows and process them into a list of string builders
IEnumerable <string> rowValues = FileOffsets.Select(rowOffset => fileStreamReader.ReadRow(rowOffset, Columns)[0].DisplayValue);
rows = new[] { new[] { string.Join(string.Empty, rowValues) } };
}
else
{
// Figure out which rows we need to read back
IEnumerable <long> rowOffsets = FileOffsets.Skip(startRow).Take(rowCount);
// Iterate over the rows we need and process them into output
rows = rowOffsets.Select(rowOffset =>
fileStreamReader.ReadRow(rowOffset, Columns).Select(cell => cell.DisplayValue).ToArray())
.ToArray();
}
}
// Retrieve the subset of the results as per the request
return new ResultSetSubset
{
Rows = rows,
RowCount = rows.Length
};
}));
}
/// <summary>
/// Returns a specific row from the result set.
/// </summary>
/// <remarks>
/// Creates a new file reader for a single reader. This method should only be used for one
/// off requests, not for requesting a large subset of the results.
/// </remarks>
/// <param name="rowId">The internal ID of the row to read</param>
/// <returns>The requested row</returns>
public IList <DbCellValue> GetRow(long rowId)
{
// Sanity check to make sure that results read has started
if (!hasStartedRead)
{
throw new InvalidOperationException(SR.QueryServiceResultSetNotRead);
}
// Sanity check to make sure that the row exists
if (rowId >= RowCount)
{
throw new ArgumentOutOfRangeException(nameof(rowId), SR.QueryServiceResultSetStartRowOutOfRange);
}
using (IFileStreamReader fileStreamReader = fileStreamFactory.GetReader(outputFileName))
{
return(fileStreamReader.ReadRow(fileOffsets[rowId], rowId, Columns));
}
}
/// <summary>
/// Generates the execution plan from the table returned
/// </summary>
/// <returns>An execution plan object</returns>
public Task <ExecutionPlan> GetExecutionPlan()
{
// Process the action just in case it hasn't been yet
ProcessSpecialAction();
// Sanity check to make sure that results read has started
if (!hasStartedRead)
{
throw new InvalidOperationException(SR.QueryServiceResultSetNotRead);
}
// Check that we this result set contains a showplan
if (!specialAction.ExpectYukonXMLShowPlan)
{
throw new Exception(SR.QueryServiceExecutionPlanNotFound);
}
return(Task.Factory.StartNew(() =>
{
string content;
string format = null;
using (IFileStreamReader fileStreamReader = fileStreamFactory.GetReader(outputFileName))
{
// Determine the format and get the first col/row of XML
content = fileStreamReader.ReadRow(0, 0, Columns)[0].DisplayValue;
if (specialAction.ExpectYukonXMLShowPlan)
{
format = "xml";
}
}
return new ExecutionPlan
{
Format = format,
Content = content
};
}));
}