private List <PageTag> WriteColumn(DataColumn column,
Thrift.SchemaElement tse,
IDataTypeHandler dataTypeHandler,
int maxRepetitionLevel,
int maxDefinitionLevel)
{
var pages = new List <PageTag>();
/*
* Page header must preceeed actual data (compressed or not) however it contains both
* the uncompressed and compressed data size which we don't know! This somehow limits
* the write efficiency.
*/
using (var ms = new MemoryStream())
{
Thrift.PageHeader dataPageHeader = _footer.CreateDataPage(column.TotalCount);
//chain streams together so we have real streaming instead of wasting undefraggable LOH memory
using (GapStream pageStream = DataStreamFactory.CreateWriter(ms, _compressionMethod, true))
{
using (var writer = new BinaryWriter(pageStream, Encoding.UTF8, true))
{
if (maxRepetitionLevel > 0)
{
WriteLevels(writer, column.RepetitionLevels, maxRepetitionLevel);
}
if (maxDefinitionLevel > 0)
{
WriteLevels(writer, column.DefinitionLevels, maxDefinitionLevel);
}
dataTypeHandler.Write(tse, writer, column.DefinedData);
writer.Flush();
}
pageStream.Flush(); //extremely important to flush the stream as some compression algorithms don't finish writing
dataPageHeader.Uncompressed_page_size = (int)pageStream.Position;
}
dataPageHeader.Compressed_page_size = (int)ms.Position;
//write the header in
int headerSize = _thriftStream.Write(dataPageHeader);
ms.Position = 0;
ms.CopyTo(_stream);
var dataTag = new PageTag
{
HeaderMeta = dataPageHeader,
HeaderSize = headerSize
};
pages.Add(dataTag);
}
return(pages);
}
private List <PageTag> WriteColumn(DataColumn column,
Thrift.SchemaElement tse,
IDataTypeHandler dataTypeHandler,
int maxRepetitionLevel,
int maxDefinitionLevel)
{
var pages = new List <PageTag>();
/*
* Page header must preceeed actual data (compressed or not) however it contains both
* the uncompressed and compressed data size which we don't know! This somehow limits
* the write efficiency.
*/
using (var ms = new MemoryStream())
{
Thrift.PageHeader dataPageHeader = _footer.CreateDataPage(column.Data.Length);
//chain streams together so we have real streaming instead of wasting undefraggable LOH memory
using (GapStream pageStream = DataStreamFactory.CreateWriter(ms, _compressionMethod, _compressionLevel, true))
{
using (var writer = new BinaryWriter(pageStream, Encoding.UTF8, true))
{
if (column.RepetitionLevels != null)
{
WriteLevels(writer, column.RepetitionLevels, column.RepetitionLevels.Length, maxRepetitionLevel);
}
Array data = column.Data;
if (maxDefinitionLevel > 0)
{
data = column.PackDefinitions(maxDefinitionLevel, out int[] definitionLevels, out int definitionLevelsLength, out int nullCount);
//last chance to capture null count as null data is compressed now
column.Statistics.NullCount = nullCount;
try
{
WriteLevels(writer, definitionLevels, definitionLevelsLength, maxDefinitionLevel);
}
finally
{
if (definitionLevels != null)
{
ArrayPool <int> .Shared.Return(definitionLevels);
}
}
}
else
{
//no defitions means no nulls
column.Statistics.NullCount = 0;
}
dataTypeHandler.Write(tse, writer, data, column.Statistics);
writer.Flush();
}
pageStream.Flush(); //extremely important to flush the stream as some compression algorithms don't finish writing
pageStream.MarkWriteFinished();
dataPageHeader.Uncompressed_page_size = (int)pageStream.Position;
}
dataPageHeader.Compressed_page_size = (int)ms.Position;
//write the header in
dataPageHeader.Data_page_header.Statistics = column.Statistics.ToThriftStatistics(dataTypeHandler, _schemaElement);
int headerSize = _thriftStream.Write(dataPageHeader);
ms.Position = 0;
ms.CopyTo(_stream);
var dataTag = new PageTag
{
HeaderMeta = dataPageHeader,
HeaderSize = headerSize
};
pages.Add(dataTag);
}
return(pages);
}