TraceBuffer Class Reference

This class is used for storing unstructured optimizer trace text (as used by the Hypergraph optimizer). More...

#include <optimizer_trace.h>

Inheritance diagram for TraceBuffer:

Public Member Functions
int_type	overflow (int_type ch) override
	Called by std::ostream if the current segment is full. More...
template<typename Sink >
void	ForEach (Sink sink) const
	Apply 'sink' to each character in the trace text. More...
template<typename Sink >
void	ForEachRemove (Sink sink)
	Apply 'sink' to each character in the trace text. More...
std::string	ToString () const
	Return a copy of the contents as a string. More...

Static Public Attributes
static constexpr size_t	kSegmentSize = 4096
	The size of each consecutive buffer. More...

Private Types
using	Segment = std::array< char, kSegmentSize >
	A consecutive buffer. More...
using	DequeType = std::deque< Segment >
	The sequence of consecutive buffers. More...

Private Attributes
DequeType	m_segments
	The sequence of segments. More...

Detailed Description

This class is used for storing unstructured optimizer trace text (as used by the Hypergraph optimizer).

It is used as the std::streambuf object of an associated std::ostream (which writes the formatted text into a TraceBuffer object). The text is stored in a non-consecutive sequence of segments, where each segment has a chunk of consecutive memory. That way, the buffer can grow without having to copy the text into ever bigger buffers of consecutive memory.

Member Typedef Documentation

DequeType

using TraceBuffer::DequeType = std::deque<Segment>

private

The sequence of consecutive buffers.

Segment

using TraceBuffer::Segment = std::array<char, kSegmentSize>

private

A consecutive buffer.

Member Function Documentation

ForEach()

template<typename Sink >

void TraceBuffer::ForEach ( Sink  sink ) const

inline

Apply 'sink' to each character in the trace text.

ForEachRemove()

template<typename Sink >

void TraceBuffer::ForEachRemove ( Sink  sink )

inline

Apply 'sink' to each character in the trace text.

Free each segment when its contents have been consumed.

overflow()

int_type TraceBuffer::overflow ( int_type  ch )

inlineoverride

Called by std::ostream if the current segment is full.

Allocate a new segment and put 'ch' at the beginning of it.

ToString()

std::string TraceBuffer::ToString ( ) const

inline

Return a copy of the contents as a string.

This may be expensive for large traces, and is only intended for unit tests.

Member Data Documentation

kSegmentSize

constexpr size_t TraceBuffer::kSegmentSize = 4096

staticconstexpr

The size of each consecutive buffer.

m_segments

DequeType TraceBuffer::m_segments

private

The sequence of segments.

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The documentation for this class was generated from the following file:

• sql/join_optimizer/optimizer_trace.h