public DocumentDataContainerEnumerator_BulkPkScan(
int untrimmedCount, DriverRowData rowData, DocumentDataContainer dataContainer, List<FieldMetadata> fields, IDriverDataEnumerator inputDataEnumerator)
: base(untrimmedCount, rowData, dataContainer, fields, fields.Count - 1)
{
if (inputDataEnumerator == null)
{
throw new ArgumentNullException("inputDataEnumerator");
}
m_inputEnumerator = inputDataEnumerator;
ReadStructureAndTakeLocks();
}
public void AttachInputDataEnumerator(IDriverDataEnumerator inputDataEnumerator)
{
if (inputDataEnumerator == null)
{
throw new ArgumentNullException("inputDataEnumerator");
}
if (InputDataEnumerator != null)
{
throw new InvalidOperationException("Cannot reassign input data enumerator");
}
InputDataEnumerator = inputDataEnumerator;
}
public DocumentDataContainerEnumerator_BulkPkScan(
int untrimmedCount, DriverRowData rowData, DocumentDataContainer dataContainer, List <FieldMetadata> fields, IDriverDataEnumerator inputDataEnumerator)
:
base(untrimmedCount, rowData, dataContainer, fields, fields.Count - 1)
{
if (inputDataEnumerator == null)
{
throw new ArgumentNullException("inputDataEnumerator");
}
m_inputEnumerator = inputDataEnumerator;
ReadStructureAndTakeLocks();
}
private bool WriteItems(
RequestExecutionContext context, RequestExecutionBuffer buffer, IDriverDataEnumerator sourceEnumerator, bool havePendingDriverRow)
{
// have to check for disposal here, because this method gets invoked in a loop
if (m_disposed)
{
buffer.Error = new ObjectDisposedException("This data engine has been disposed");
return false;
}
if (sourceEnumerator == null)
{
return false;
}
var stream = buffer.Stream;
var writer = buffer.Writer;
var cts = context.CancellationTokenSource;
buffer.RowsOutput = 0;
var hasPendingWrite = false;
var mustReturnDataset = context.Request.ReturnDataset;
var lastValidLength = stream.Length;
var totalRowsProduced = context.TotalRowsProduced;
var recordsAffected = context.RecordsAffected;
var rowsOutputLocally = 0;
var func = context.ParsedRequest.BaseDataset.Paging.Offset;
var pagingOffset = ReferenceEquals(func, null) ? 0 : func(context.ParsedRequest.Params.InputValues);
func = context.ParsedRequest.BaseDataset.Paging.PageSize;
var pageSize = ReferenceEquals(func, null) ? Int32.MaxValue : func(context.ParsedRequest.Params.InputValues);
// one row might not have fit into previous buffer, let's write it now
if (havePendingDriverRow)
{
try
{
// no need to apply paging and where clause for pending row: we applied them already
// also expect that a buffer can accomodate at least one row
// - this requires that rows are never larger than RequestExecutionBuffer.MaxBytesPerBuffer
ProduceOutputRow(context);
context.OutputDataBuffer.Write(writer);
rowsOutputLocally++;
lastValidLength = stream.Length;
}
catch (Exception e)
{
throw new Exception("Internal buffer may be too small to fit even a single data row", e);
}
}
// now let's deal with remaining items in the enumerator
while (lastValidLength < RequestExecutionBuffer.MaxBytesPerBuffer && !cts.IsCancellationRequested)
{
if (recordsAffected >= pageSize || !sourceEnumerator.MoveNext())
{
// enough rows accumulated, or no more rows from driver: halt
break;
}
// if record satisfies WHERE criteria, it gets counted into pre-paging total
if (ApplyWhereClause(context))
{
var isAccumulating = totalRowsProduced >= pagingOffset;
totalRowsProduced++;
if (isAccumulating)
{
// once WHERE has been evaluated, read all remaining fields for this row into the buffer
sourceEnumerator.FetchAdditionalFields();
// output row number is needed for "rownumoutput()" Pql function
context.ClauseEvaluationContext.RowNumberInOutput = recordsAffected;
// increment counter BEFORE producing and writing
// even if we fail to write into current buffer, we'll write into next one
recordsAffected++;
// this will be false when clients do ExecuteNonQuery or Prepare
if (mustReturnDataset)
{
// produce SELECT (output scheme) from FROM (raw data from storage driver)
var estimatedSize = ProduceOutputRow(context);
if (lastValidLength + estimatedSize > RequestExecutionBuffer.MaxBytesPerBuffer)
{
// store pending write and return
hasPendingWrite = true;
break;
}
// MemoryStream will throw NotSupportedException when trying to expand beyond fixed buffer size
// this should never happen (see check above)
context.OutputDataBuffer.Write(writer);
// this counter gets incremented AFTER writing,
// because it indicates how many rows have in fact been put into current block
rowsOutputLocally++;
}
lastValidLength = stream.Length;
}
// row number is needed for "rownum()" Pql function
context.ClauseEvaluationContext.RowNumber++;
}
}
buffer.RowsOutput = rowsOutputLocally;
context.RecordsAffected = recordsAffected;
context.TotalRowsProduced = totalRowsProduced;
stream.Seek(0, SeekOrigin.Begin);
return hasPendingWrite;
}
private void StartProduction(
RequestExecutionContext context, RequestExecutionBuffer buffer, out IDriverDataEnumerator sourceEnumerator)
{
ReadRequest(context);
context.AttachContainerDescriptor(m_containerDescriptor);
if (!context.CacheInfo.HaveParsingResults)
{
lock (context.CacheInfo)
{
context.CacheInfo.CheckIsError();
if (!context.CacheInfo.HaveParsingResults)
{
try
{
ParseRequest(context.Request, context.RequestBulk, context.CacheInfo.ParsedRequest, context.CancellationTokenSource.Token);
CompileClauses(context.ContainerDescriptor, context.CacheInfo);
Thread.MemoryBarrier();
context.CacheInfo.HaveParsingResults = true;
}
catch (Exception e)
{
// make sure that partially complete results do not become visible
context.CacheInfo.IsError(e);
throw;
}
}
}
}
context.CacheInfo.WriteParsingResults(context.ParsedRequest);
if (context.ParsedRequest.SpecialCommand.IsSpecialCommand)
{
sourceEnumerator = null;
ExecuteSpecialCommandStatement(context, buffer);
return;
}
// structure of output buffer depends on which fields client is asking for
// therefore, we re-create and re-attach a driver output buffer for every request
context.AttachDriverOutputBufferAndInputParameters(
QueryParser.CreateDriverRowDataBuffer(context.ParsedRequest.BaseDataset.BaseFields),
context.ParsedRequest);
// this enumerator will yield our own driverOutputBuffer for every source record
// e.g. the very same context.DriverOutputBuffer is going to be yielded N times from this enumerator
if (context.ParsedRequest.StatementType == StatementType.Insert)
{
if (context.ParsedRequest.IsBulk)
{
sourceEnumerator = CreateInputDataEnumerator(context);
//m_storageDriver.AllocateCapacityForDocumentType(context.ParsedRequest.TargetEntity.DocumentType, context.RequestBulk.InputItemsCount);
}
else
{
sourceEnumerator = CreatePseudoEnumeratorForInsertValues(context);
}
}
else
{
if (context.ParsedRequest.IsBulk)
{
// for SELECT and DELETE, we only use PK values from the input enumerator
// for UPDATE, we use both PK values and other field values from input enumerator
context.AttachInputDataEnumerator(CreateInputDataEnumerator(context));
}
// driver returns set of rows related to given set of PK values
// for a bulk request, sourceEnumerator will yield exactly one item for each item in input enumerator
sourceEnumerator = m_storageDriver.GetData(context);
}
switch (context.ParsedRequest.StatementType)
{
case StatementType.Select:
{
context.AttachResponseHeaders(CreateResponseSchemeForSelect(context));
context.PrepareBuffersForSelect();
context.ResponseHeaders.RecordsAffected = 0;
}
break;
case StatementType.Update:
{
context.AttachResponseHeaders(new DataResponse(0, "Update successful"));
context.PrepareBuffersForUpdate();
ExecuteInsertUpdateStatement(context, buffer, sourceEnumerator, DriverChangeType.Update);
context.ResponseHeaders.RecordsAffected = context.RecordsAffected;
}
break;
case StatementType.Delete:
{
context.AttachResponseHeaders(new DataResponse(0, "Delete successful"));
context.PrepareBuffersForDelete();
ExecuteDeleteStatement(context, buffer, sourceEnumerator);
context.ResponseHeaders.RecordsAffected = context.RecordsAffected;
}
break;
case StatementType.Insert:
{
context.AttachResponseHeaders(new DataResponse(0, "Insert successful"));
context.PrepareChangeBufferForInsert();
ExecuteInsertUpdateStatement(context, buffer, sourceEnumerator, DriverChangeType.Insert);
context.ResponseHeaders.RecordsAffected = context.RecordsAffected;
}
break;
default:
throw new Exception("Invalid statement type: " + context.ParsedRequest.StatementType);
}
}
private void ExecuteInsertUpdateStatement(RequestExecutionContext context, RequestExecutionBuffer buffer, IDriverDataEnumerator sourceEnumerator, DriverChangeType changeType)
{
if (sourceEnumerator == null)
{
return;
}
buffer.RowsOutput = 0;
var cts = context.CancellationTokenSource;
var updates = context.ParsedRequest.Modify.UpdateAssignments;
context.ClauseEvaluationContext.RowNumber = 0;
context.ClauseEvaluationContext.RowNumberInOutput = context.ClauseEvaluationContext.RowNumber;
var changeBuffer = context.ClauseEvaluationContext.ChangeBuffer;
var changeset = m_storageDriver.CreateChangeset(changeBuffer, context.ParsedRequest.IsBulk);
try
{
changeBuffer.ChangeType = changeType;
while (!cts.IsCancellationRequested && sourceEnumerator.MoveNext())
{
// if record satisfies WHERE criteria, compute updated values and give them to driver
if (ApplyWhereClause(context))
{
// make sure we have values for fields in SET expressions
sourceEnumerator.FetchAdditionalFields();
BitVector.SetAll(changeBuffer.Data.NotNulls, false);
for (var ordinal = 0; ordinal < updates.Count; ordinal++)
{
if (updates[ordinal].CompiledExpression != null)
{
updates[ordinal].CompiledExpression(context.ClauseEvaluationContext);
}
}
// this will either take internal entity id from current data row
// or from the computed change buffer data (for non-bulk inserts)
sourceEnumerator.FetchInternalEntityIdIntoChangeBuffer(changeBuffer, context);
m_storageDriver.AddChange(changeset);
}
// row number is needed for "rownum()" Pql function
context.ClauseEvaluationContext.RowNumber++;
// output row number is needed for "rownumoutput()" Pql function
context.ClauseEvaluationContext.RowNumberInOutput = context.ClauseEvaluationContext.RowNumber;
}
if (!cts.IsCancellationRequested)
{
context.RecordsAffected = m_storageDriver.Apply(changeset);
}
}
catch
{
m_storageDriver.Discard(changeset);
throw;
}
}
private void ExecuteDeleteStatement(RequestExecutionContext context, RequestExecutionBuffer buffer, IDriverDataEnumerator sourceEnumerator)
{
if (sourceEnumerator == null)
{
return;
}
buffer.RowsOutput = 0;
var cts = context.CancellationTokenSource;
context.ClauseEvaluationContext.RowNumber = 0;
context.ClauseEvaluationContext.RowNumberInOutput = context.ClauseEvaluationContext.RowNumber;
var changeBuffer = context.ClauseEvaluationContext.ChangeBuffer;
var changeset = m_storageDriver.CreateChangeset(changeBuffer, context.ParsedRequest.IsBulk);
try
{
changeBuffer.ChangeType = DriverChangeType.Delete;
while (!cts.IsCancellationRequested && sourceEnumerator.MoveNext())
{
// if record satisfies WHERE criteria, compute updated values and give them to driver
if (ApplyWhereClause(context))
{
// load internal ID, it is needed
sourceEnumerator.FetchAdditionalFields();
sourceEnumerator.FetchInternalEntityIdIntoChangeBuffer(changeBuffer, context);
m_storageDriver.AddChange(changeset);
}
// row number is needed for "rownum()" Pql function
context.ClauseEvaluationContext.RowNumber++;
// output row number is needed for "rownumoutput()" Pql function
context.ClauseEvaluationContext.RowNumberInOutput = context.ClauseEvaluationContext.RowNumber;
}
if (!cts.IsCancellationRequested)
{
context.RecordsAffected = m_storageDriver.Apply(changeset);
}
}
catch
{
m_storageDriver.Discard(changeset);
throw;
}
}
private void ExecuteInsertUpdateStatement(RequestExecutionContext context, RequestExecutionBuffer buffer, IDriverDataEnumerator sourceEnumerator, DriverChangeType changeType)
{
if (sourceEnumerator == null)
{
return;
}
buffer.RowsOutput = 0;
var cts = context.CancellationTokenSource;
var updates = context.ParsedRequest.Modify.UpdateAssignments;
context.ClauseEvaluationContext.RowNumber = 0;
context.ClauseEvaluationContext.RowNumberInOutput = context.ClauseEvaluationContext.RowNumber;
var changeBuffer = context.ClauseEvaluationContext.ChangeBuffer;
var changeset = m_storageDriver.CreateChangeset(changeBuffer, context.ParsedRequest.IsBulk);
try
{
changeBuffer.ChangeType = changeType;
while (!cts.IsCancellationRequested && sourceEnumerator.MoveNext())
{
// if record satisfies WHERE criteria, compute updated values and give them to driver
if (ApplyWhereClause(context))
{
// make sure we have values for fields in SET expressions
sourceEnumerator.FetchAdditionalFields();
BitVector.SetAll(changeBuffer.Data.NotNulls, false);
for (var ordinal = 0; ordinal < updates.Count; ordinal++)
{
if (updates[ordinal].CompiledExpression != null)
{
updates[ordinal].CompiledExpression(context.ClauseEvaluationContext);
}
}
// this will either take internal entity id from current data row
// or from the computed change buffer data (for non-bulk inserts)
sourceEnumerator.FetchInternalEntityIdIntoChangeBuffer(changeBuffer, context);
m_storageDriver.AddChange(changeset);
}
// row number is needed for "rownum()" Pql function
context.ClauseEvaluationContext.RowNumber++;
// output row number is needed for "rownumoutput()" Pql function
context.ClauseEvaluationContext.RowNumberInOutput = context.ClauseEvaluationContext.RowNumber;
}
if (!cts.IsCancellationRequested)
{
context.RecordsAffected = m_storageDriver.Apply(changeset);
}
}
catch
{
m_storageDriver.Discard(changeset);
throw;
}
}
private void ExecuteDeleteStatement(RequestExecutionContext context, RequestExecutionBuffer buffer, IDriverDataEnumerator sourceEnumerator)
{
if (sourceEnumerator == null)
{
return;
}
buffer.RowsOutput = 0;
var cts = context.CancellationTokenSource;
context.ClauseEvaluationContext.RowNumber = 0;
context.ClauseEvaluationContext.RowNumberInOutput = context.ClauseEvaluationContext.RowNumber;
var changeBuffer = context.ClauseEvaluationContext.ChangeBuffer;
var changeset = m_storageDriver.CreateChangeset(changeBuffer, context.ParsedRequest.IsBulk);
try
{
changeBuffer.ChangeType = DriverChangeType.Delete;
while (!cts.IsCancellationRequested && sourceEnumerator.MoveNext())
{
// if record satisfies WHERE criteria, compute updated values and give them to driver
if (ApplyWhereClause(context))
{
// load internal ID, it is needed
sourceEnumerator.FetchAdditionalFields();
sourceEnumerator.FetchInternalEntityIdIntoChangeBuffer(changeBuffer, context);
m_storageDriver.AddChange(changeset);
}
// row number is needed for "rownum()" Pql function
context.ClauseEvaluationContext.RowNumber++;
// output row number is needed for "rownumoutput()" Pql function
context.ClauseEvaluationContext.RowNumberInOutput = context.ClauseEvaluationContext.RowNumber;
}
if (!cts.IsCancellationRequested)
{
context.RecordsAffected = m_storageDriver.Apply(changeset);
}
}
catch
{
m_storageDriver.Discard(changeset);
throw;
}
}
private void StartProduction(
RequestExecutionContext context, RequestExecutionBuffer buffer, out IDriverDataEnumerator sourceEnumerator)
{
ReadRequest(context);
context.AttachContainerDescriptor(m_containerDescriptor);
if (!context.CacheInfo.HaveParsingResults)
{
lock (context.CacheInfo)
{
context.CacheInfo.CheckIsError();
if (!context.CacheInfo.HaveParsingResults)
{
try
{
ParseRequest(context.Request, context.RequestBulk, context.CacheInfo.ParsedRequest, context.CancellationTokenSource.Token);
CompileClauses(context.ContainerDescriptor, context.CacheInfo);
Thread.MemoryBarrier();
context.CacheInfo.HaveParsingResults = true;
}
catch (Exception e)
{
// make sure that partially complete results do not become visible
context.CacheInfo.IsError(e);
throw;
}
}
}
}
context.CacheInfo.WriteParsingResults(context.ParsedRequest);
if (context.ParsedRequest.SpecialCommand.IsSpecialCommand)
{
sourceEnumerator = null;
ExecuteSpecialCommandStatement(context, buffer);
return;
}
// structure of output buffer depends on which fields client is asking for
// therefore, we re-create and re-attach a driver output buffer for every request
context.AttachDriverOutputBufferAndInputParameters(
QueryParser.CreateDriverRowDataBuffer(context.ParsedRequest.BaseDataset.BaseFields),
context.ParsedRequest);
// this enumerator will yield our own driverOutputBuffer for every source record
// e.g. the very same context.DriverOutputBuffer is going to be yielded N times from this enumerator
if (context.ParsedRequest.StatementType == StatementType.Insert)
{
if (context.ParsedRequest.IsBulk)
{
sourceEnumerator = CreateInputDataEnumerator(context);
//m_storageDriver.AllocateCapacityForDocumentType(context.ParsedRequest.TargetEntity.DocumentType, context.RequestBulk.InputItemsCount);
}
else
{
sourceEnumerator = CreatePseudoEnumeratorForInsertValues(context);
}
}
else
{
if (context.ParsedRequest.IsBulk)
{
// for SELECT and DELETE, we only use PK values from the input enumerator
// for UPDATE, we use both PK values and other field values from input enumerator
context.AttachInputDataEnumerator(CreateInputDataEnumerator(context));
}
// driver returns set of rows related to given set of PK values
// for a bulk request, sourceEnumerator will yield exactly one item for each item in input enumerator
sourceEnumerator = m_storageDriver.GetData(context);
}
switch (context.ParsedRequest.StatementType)
{
case StatementType.Select:
{
context.AttachResponseHeaders(CreateResponseSchemeForSelect(context));
context.PrepareBuffersForSelect();
context.ResponseHeaders.RecordsAffected = 0;
}
break;
case StatementType.Update:
{
context.AttachResponseHeaders(new DataResponse(0, "Update successful"));
context.PrepareBuffersForUpdate();
ExecuteInsertUpdateStatement(context, buffer, sourceEnumerator, DriverChangeType.Update);
context.ResponseHeaders.RecordsAffected = context.RecordsAffected;
}
break;
case StatementType.Delete:
{
context.AttachResponseHeaders(new DataResponse(0, "Delete successful"));
context.PrepareBuffersForDelete();
ExecuteDeleteStatement(context, buffer, sourceEnumerator);
context.ResponseHeaders.RecordsAffected = context.RecordsAffected;
}
break;
case StatementType.Insert:
{
context.AttachResponseHeaders(new DataResponse(0, "Insert successful"));
context.PrepareChangeBufferForInsert();
ExecuteInsertUpdateStatement(context, buffer, sourceEnumerator, DriverChangeType.Insert);
context.ResponseHeaders.RecordsAffected = context.RecordsAffected;
}
break;
default:
throw new Exception("Invalid statement type: " + context.ParsedRequest.StatementType);
}
}
/// <summary>
/// <see cref="ProducerThreadMethod"/> works in parallel with RPM's <see cref="RequestProcessingManager.WriteTo"/>.
/// RPM supplies empty buffers to be filled with data into <see cref="RequestExecutionContext.BuffersRing"/> and consumes them on the other end.
/// The data ring has very limited number of buffers.
/// RPM is limited by network throughput and Producer's speed.
/// Producer is limited by underlying storage driver, local processing speed and RPM's consumption of complete buffers.
/// The difference between the two: RPM <see cref="RequestProcessingManager.WriteTo"/> is scheduled for execution by service infrastructure (WCF),
/// whereas <see cref="DataEngine.ProducerThreadMethod"/> is scheduled by RPM itself, when it invokes <see cref="IDataEngine.BeginExecution"/>.
/// </summary>
void ProducerThreadMethod(RequestExecutionContext context)
{
PqlEngineSecurityContext.Set(new PqlClientSecurityContext(
context.AuthContext.UserId, "dummy", context.AuthContext.TenantId, context.AuthContext.ContextId));
var executionPending = true;
IDriverDataEnumerator sourceEnumerator = null;
try
{
// row number is needed for "rownum()" Pql function
context.ClauseEvaluationContext.RowNumber = 0;
// Our production is limited by the network throughput.
// Production will also be aborted if the destination sink stops accepting.
// In that case, ConsumingEnumerable will either throw or stop yielding.
bool havePendingDriverRow = false;
foreach (var buffer in context.BuffersRing.ConsumeProcessingTasks(context.CancellationTokenSource.Token)
)
{
buffer.Cleanup();
try
{
if (executionPending)
{
executionPending = false;
// read network protocol message
// parse-compile expressions and collect information for execution plan
// generate response headers and fetch data from Redis
// this place fails most often, because of Pql compilation or storage driver connectivity failures
StartProduction(context, buffer, out sourceEnumerator);
if (context.Request.ReturnDataset)
{
// write response headers BEFORE the query processing is completed
// records affected and whatever other stats will be zero
Serializer.SerializeWithLengthPrefix(buffer.Stream, context.ResponseHeaders, PrefixStyle.Base128);
}
}
// go through retrieved data
havePendingDriverRow = ((DataEngine)context.Engine).WriteItems(
context, buffer, sourceEnumerator, havePendingDriverRow);
// some consistency checks
if (context.Request.ReturnDataset)
{
if (havePendingDriverRow && buffer.RowsOutput == 0)
{
throw new Exception("Internal error: should not have pending row when no data is produced");
}
}
else
{
if (havePendingDriverRow)
{
throw new Exception("Internal error: should not have pending row when no dataset is requested");
}
if (buffer.Stream.Length > 0)
{
throw new Exception("Internal error: should not have written anything to stream when no dataset is requested");
}
}
// time to quit?
// no dataset requested, don't have any more data, or enough rows accumulated for requested page of results?
if (buffer.RowsOutput == 0 || buffer.IsFailed || !context.Request.ReturnDataset)
{
if (!context.Request.ReturnDataset)
{
// if there is no dataset sent, write response headers AFTER processing the query
// records affected and whatever other stats are meaningful
context.ResponseHeaders.RecordsAffected = context.RecordsAffected;
Serializer.SerializeWithLengthPrefix(buffer.Stream, context.ResponseHeaders, PrefixStyle.Base128);
}
break;
}
}
catch (Exception e)
{
buffer.Error = e;
context.TrySetLastError(e);
m_tracer.Exception(e);
// this will go to client, and overwrite whatever we managed to put into buffer before failure
using (var writer = new PqlErrorDataWriter(1, e, false))
{
buffer.Stream.SetLength(0);
writer.WriteTo(buffer.Stream);
}
return;
}
finally
{
// return the buffer back to the ring in any case
context.BuffersRing.ReturnCompletedTask(buffer);
}
}
}
catch (OperationCanceledException e)
{
context.Cancel(e);
}
catch (Exception e)
{
if (Environment.HasShutdownStarted)
{
// nobody cares now
return;
}
var cts = context.CancellationTokenSource;
if (cts != null && !cts.IsCancellationRequested)
{
m_tracer.Exception(e);
context.Cancel(e);
}
}
finally
{
var ring = context.BuffersRing;
if (ring != null)
{
ring.CompleteAddingCompletedTasks();
}
if (sourceEnumerator != null)
{
// release driver-level resources & locks
sourceEnumerator.Dispose();
}
}
}
private bool WriteItems(
RequestExecutionContext context, RequestExecutionBuffer buffer, IDriverDataEnumerator sourceEnumerator, bool havePendingDriverRow)
{
// have to check for disposal here, because this method gets invoked in a loop
if (m_disposed)
{
buffer.Error = new ObjectDisposedException("This data engine has been disposed");
return(false);
}
if (sourceEnumerator == null)
{
return(false);
}
var stream = buffer.Stream;
var writer = buffer.Writer;
var cts = context.CancellationTokenSource;
buffer.RowsOutput = 0;
var hasPendingWrite = false;
var mustReturnDataset = context.Request.ReturnDataset;
var lastValidLength = stream.Length;
var totalRowsProduced = context.TotalRowsProduced;
var recordsAffected = context.RecordsAffected;
var rowsOutputLocally = 0;
var func = context.ParsedRequest.BaseDataset.Paging.Offset;
var pagingOffset = ReferenceEquals(func, null) ? 0 : func(context.ParsedRequest.Params.InputValues);
func = context.ParsedRequest.BaseDataset.Paging.PageSize;
var pageSize = ReferenceEquals(func, null) ? Int32.MaxValue : func(context.ParsedRequest.Params.InputValues);
// one row might not have fit into previous buffer, let's write it now
if (havePendingDriverRow)
{
try
{
// no need to apply paging and where clause for pending row: we applied them already
// also expect that a buffer can accomodate at least one row
// - this requires that rows are never larger than RequestExecutionBuffer.MaxBytesPerBuffer
ProduceOutputRow(context);
context.OutputDataBuffer.Write(writer);
rowsOutputLocally++;
lastValidLength = stream.Length;
}
catch (Exception e)
{
throw new Exception("Internal buffer may be too small to fit even a single data row", e);
}
}
// now let's deal with remaining items in the enumerator
while (lastValidLength < RequestExecutionBuffer.MaxBytesPerBuffer && !cts.IsCancellationRequested)
{
if (recordsAffected >= pageSize || !sourceEnumerator.MoveNext())
{
// enough rows accumulated, or no more rows from driver: halt
break;
}
// if record satisfies WHERE criteria, it gets counted into pre-paging total
if (ApplyWhereClause(context))
{
var isAccumulating = totalRowsProduced >= pagingOffset;
totalRowsProduced++;
if (isAccumulating)
{
// once WHERE has been evaluated, read all remaining fields for this row into the buffer
sourceEnumerator.FetchAdditionalFields();
// output row number is needed for "rownumoutput()" Pql function
context.ClauseEvaluationContext.RowNumberInOutput = recordsAffected;
// increment counter BEFORE producing and writing
// even if we fail to write into current buffer, we'll write into next one
recordsAffected++;
// this will be false when clients do ExecuteNonQuery or Prepare
if (mustReturnDataset)
{
// produce SELECT (output scheme) from FROM (raw data from storage driver)
var estimatedSize = ProduceOutputRow(context);
if (lastValidLength + estimatedSize > RequestExecutionBuffer.MaxBytesPerBuffer)
{
// store pending write and return
hasPendingWrite = true;
break;
}
// MemoryStream will throw NotSupportedException when trying to expand beyond fixed buffer size
// this should never happen (see check above)
context.OutputDataBuffer.Write(writer);
// this counter gets incremented AFTER writing,
// because it indicates how many rows have in fact been put into current block
rowsOutputLocally++;
}
lastValidLength = stream.Length;
}
// row number is needed for "rownum()" Pql function
context.ClauseEvaluationContext.RowNumber++;
}
}
buffer.RowsOutput = rowsOutputLocally;
context.RecordsAffected = recordsAffected;
context.TotalRowsProduced = totalRowsProduced;
stream.Seek(0, SeekOrigin.Begin);
return(hasPendingWrite);
}
public IDriverDataEnumerator GetBulkUpdateEnumerator(List<FieldMetadata> fields, DriverRowData driverRow, IDriverDataEnumerator inputDataEnumerator)
{
var untrimmedCount = m_untrimmedDocumentCount;
if (untrimmedCount == 0)
{
return null;
}
return new DocumentDataContainerEnumerator_BulkPkScan(untrimmedCount, driverRow, this, fields, inputDataEnumerator);
}
public IDriverDataEnumerator GetBulkUpdateEnumerator(List <FieldMetadata> fields, DriverRowData driverRow, IDriverDataEnumerator inputDataEnumerator)
{
var untrimmedCount = m_untrimmedDocumentCount;
if (untrimmedCount == 0)
{
return(null);
}
return(new DocumentDataContainerEnumerator_BulkPkScan(untrimmedCount, driverRow, this, fields, inputDataEnumerator));
}
public void AttachInputDataEnumerator(IDriverDataEnumerator inputDataEnumerator)
{
if (inputDataEnumerator == null)
{
throw new ArgumentNullException("inputDataEnumerator");
}
if (InputDataEnumerator != null)
{
throw new InvalidOperationException("Cannot reassign input data enumerator");
}
InputDataEnumerator = inputDataEnumerator;
}
