duckdb::ColumnSegment Class Reference

TableFilter represents a filter pushed down into the table scan. More...

Inheritance diagram for duckdb::ColumnSegment:

Collaboration diagram for duckdb::ColumnSegment:

Public Member Functions
	ColumnSegment (DatabaseInstance &db, shared_ptr< BlockHandle > block, const LogicalType &type, const ColumnSegmentType segment_type, const idx_t count, const CompressionFunction &function_p, BaseStatistics statistics, const block_id_t block_id_p, const idx_t offset, const idx_t segment_size_p, unique_ptr< ColumnSegmentState > segment_state_p=nullptr)
	Construct a column segment.
	ColumnSegment (ColumnSegment &other)
void	InitializePrefetch (PrefetchState &prefetch_state, ColumnScanState &scan_state)
void	InitializeScan (ColumnScanState &state)
void	Scan (ColumnScanState &state, idx_t scan_count, Vector &result, idx_t result_offset, ScanVectorType scan_type)
	Scan one vector from this segment.
void	Select (ColumnScanState &state, idx_t scan_count, Vector &result, const SelectionVector &sel, idx_t sel_count)
	Scan a subset of a vector (defined by the selection vector)
void	Filter (ColumnScanState &state, idx_t scan_count, Vector &result, SelectionVector &sel, idx_t &sel_count, const TableFilter &filter, TableFilterState &filter_state)
	Scan one vector while applying a filter to the vector, returning only the matching elements.
void	FetchRow (ColumnFetchState &state, row_t row_id, Vector &result, idx_t result_idx)
	Fetch a value of the specific row id and append it to the result.
void	Skip (ColumnScanState &state)
	Skip a scan forward to the row_index specified in the scan state.
idx_t	SegmentSize () const
void	Resize (idx_t segment_size)
	Resize the block.
const CompressionFunction &	GetCompressionFunction ()
void	InitializeAppend (ColumnAppendState &state)
	Initialize an append of this segment. Appends are only supported on transient segments.
idx_t	Append (ColumnAppendState &state, UnifiedVectorFormat &data, idx_t offset, idx_t count)
	Appends a (part of) vector to the segment, returns the amount of entries successfully appended.
idx_t	FinalizeAppend (ColumnAppendState &state)
void	RevertAppend (idx_t new_count)
	Revert an append made to this segment.
void	ConvertToPersistent (QueryContext context, optional_ptr< BlockManager > block_manager, const block_id_t block_id)
void	MarkAsPersistent (shared_ptr< BlockHandle > block, uint32_t offset_in_block)
void	SetBlock (shared_ptr< BlockHandle > block, uint32_t offset)
DataPointer	GetDataPointer (idx_t row_start)
	Gets a data pointer from a persistent column segment.
block_id_t	GetBlockId ()
idx_t	GetBlockSize () const
	Returns the size of the underlying block of the segment. It is size is the size available for usage on a block.
idx_t	GetBlockOffset ()
optional_ptr< CompressedSegmentState >	GetSegmentState () const
void	VisitBlockIds (BlockIdVisitor &visitor) const
Public Member Functions inherited from duckdb::SegmentBase< ColumnSegment >
	SegmentBase (idx_t count)

Static Public Member Functions
static unique_ptr< ColumnSegment >	CreatePersistentSegment (DatabaseInstance &db, BlockManager &block_manager, block_id_t id, idx_t offset, const LogicalType &type_p, idx_t count, CompressionType compression_type, BaseStatistics statistics, unique_ptr< ColumnSegmentState > segment_state)
static unique_ptr< ColumnSegment >	CreateTransientSegment (DatabaseInstance &db, const CompressionFunction &function, const LogicalType &type, const idx_t segment_size, BlockManager &block_manager)
static idx_t	FilterSelection (SelectionVector &sel, Vector &vector, UnifiedVectorFormat &vdata, const TableFilter &filter, TableFilterState &filter_state, idx_t scan_count, idx_t &approved_tuple_count)

Public Attributes
DatabaseInstance &	db
	The database instance.
LogicalType	type
	The type stored in the column.
idx_t	type_size
	The size of the type.
ColumnSegmentType	segment_type
	The column segment type (transient or persistent)
SegmentStatistics	stats
	The statistics for the segment.
shared_ptr< BlockHandle >	block
	The block that this segment relates to.
Public Attributes inherited from duckdb::SegmentBase< ColumnSegment >
atomic< idx_t >	count
	The amount of entries in this storage chunk.

Private Member Functions
void	Scan (ColumnScanState &state, idx_t scan_count, Vector &result)
void	ScanPartial (ColumnScanState &state, idx_t scan_count, Vector &result, idx_t result_offset)

Private Attributes
reference< const CompressionFunction >	function
	The compression function.
block_id_t	block_id
	The block id that this segment relates to (persistent segment only)
idx_t	offset
	The offset into the block (persistent segment only)
idx_t	segment_size
	The allocated segment size, which is bounded by Storage::BLOCK_SIZE.
unique_ptr< CompressedSegmentState >	segment_state
	Storage associated with the compressed segment.

Detailed Description

TableFilter represents a filter pushed down into the table scan.

Constructor & Destructor Documentation

ColumnSegment()

duckdb::ColumnSegment::ColumnSegment

(

ColumnSegment &

other

)

Construct a column segment from another column segment. The other column segment becomes invalid (std::move).

Member Function Documentation

FinalizeAppend()

idx_t duckdb::ColumnSegment::FinalizeAppend

(

ColumnAppendState &

state

)

Finalize the segment for appending - no more appends can follow on this segment The segment should be compacted as much as possible Returns the number of bytes occupied within the segment

ConvertToPersistent()

void duckdb::ColumnSegment::ConvertToPersistent	(	QueryContext	context,
		optional_ptr< BlockManager >	block_manager,
		const block_id_t	block_id
	)

Convert a transient in-memory segment to a persistent segment backed by an on-disk block. Only used during checkpointing.

MarkAsPersistent()

void duckdb::ColumnSegment::MarkAsPersistent	(	shared_ptr< BlockHandle >	block,
		uint32_t	offset_in_block
	)

Updates pointers to refer to the given block and offset. This is only used when sharing a block among segments. This is invoked only AFTER the block is written.

GetBlockId()

block_id_t duckdb::ColumnSegment::GetBlockId ( )

inline

                            {
        D_ASSERT(segment_type == ColumnSegmentType::PERSISTENT);
        return block_id;
    }

GetBlockSize()

idx_t duckdb::ColumnSegment::GetBlockSize ( ) const

inline

Returns the size of the underlying block of the segment. It is size is the size available for usage on a block.

                               {
        return block->GetBlockSize();
    }

GetBlockOffset()

idx_t duckdb::ColumnSegment::GetBlockOffset ( )

inline

                           {
        D_ASSERT(segment_type == ColumnSegmentType::PERSISTENT || offset == 0);
        return offset;
    }

GetSegmentState()

optional_ptr< CompressedSegmentState > duckdb::ColumnSegment::GetSegmentState ( ) const

inline

                                                                 {
        return segment_state.get();
    }

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

• external/duckdb/duckdb.hpp