DsMrr_impl Class Reference

#include <handler.h>

Public Member Functions
	DsMrr_impl (handler *owner)
	~DsMrr_impl ()
void	init (TABLE *table_arg)
	Initialize the DsMrr_impl object. More...
int	dsmrr_init (RANGE_SEQ_IF *seq_funcs, void *seq_init_param, uint n_ranges, uint mode, HANDLER_BUFFER *buf)
	DS-MRR: Initialize and start MRR scan. More...
void	dsmrr_close ()
void	reset ()
	Resets the DS-MRR object to the state it had after being initialized. More...
int	dsmrr_fill_buffer ()
	DS-MRR: Fill the buffer with rowids and sort it by rowid. More...
int	dsmrr_next (char **range_info)
ha_rows	dsmrr_info (uint keyno, uint n_ranges, uint keys, uint *bufsz, uint *flags, Cost_estimate *cost)
ha_rows	dsmrr_info_const (uint keyno, RANGE_SEQ_IF *seq, void *seq_init_param, uint n_ranges, uint *bufsz, uint *flags, Cost_estimate *cost)

Private Member Functions
bool	choose_mrr_impl (uint keyno, ha_rows rows, uint *flags, uint *bufsz, Cost_estimate *cost)
	DS-MRR Internals: Choose between Default MRR implementation and DS-MRR. More...
bool	get_disk_sweep_mrr_cost (uint keynr, ha_rows rows, uint flags, uint *buffer_size, Cost_estimate *cost)
	Get cost of DS-MRR scan. More...

Private Attributes
handler *const	h
TABLE *	table
handler *	h2
uchar *	rowids_buf
uchar *	rowids_buf_cur
uchar *	rowids_buf_last
uchar *	rowids_buf_end
bool	dsmrr_eof
bool	is_mrr_assoc
bool	use_default_impl

Constructor & Destructor Documentation

DsMrr_impl()

DsMrr_impl::DsMrr_impl ( handler *  owner )

inline

~DsMrr_impl()

DsMrr_impl::~DsMrr_impl ( )

inline

Member Function Documentation

choose_mrr_impl()

bool DsMrr_impl::choose_mrr_impl ( uint  keyno, ha_rows  rows, uint *  flags, uint *  bufsz, Cost_estimate *  cost  )

private

DS-MRR Internals: Choose between Default MRR implementation and DS-MRR.

Make the choice between using Default MRR implementation and DS-MRR. This function contains common functionality factored out of dsmrr_info() and dsmrr_info_const(). The function assumes that the default MRR implementation's applicability requirements are satisfied.

Parameters

keyno	Index number
rows	E(full rows to be retrieved)
flags	IN MRR flags provided by the MRR user OUT If DS-MRR is chosen, flags of DS-MRR implementation else the value is not modified
bufsz	IN If DS-MRR is chosen, buffer use of DS-MRR implementation else the value is not modified
cost	IN Cost of default MRR implementation OUT If DS-MRR is chosen, cost of DS-MRR scan else the value is not modified

Return values

true	Default MRR implementation should be used
false	DS-MRR implementation should be used

dsmrr_close()

void DsMrr_impl::dsmrr_close

(

)

dsmrr_fill_buffer()

int DsMrr_impl::dsmrr_fill_buffer

(

)

DS-MRR: Fill the buffer with rowids and sort it by rowid.

{This is an internal function of DiskSweep MRR implementation} Scan the MRR ranges and collect ROWIDs (or {ROWID, range_id} pairs) into buffer. When the buffer is full or scan is completed, sort the buffer by rowid and return.

The function assumes that rowids buffer is empty when it is invoked.

Return values

0	OK, the next portion of rowids is in the buffer, properly ordered
other	Error

dsmrr_info()

ha_rows DsMrr_impl::dsmrr_info	(	uint	keyno,
		uint	n_ranges,
		uint	keys,
		uint *	bufsz,
		uint *	flags,
		Cost_estimate *	cost
	)

dsmrr_info_const()

ha_rows DsMrr_impl::dsmrr_info_const	(	uint	keyno,
		RANGE_SEQ_IF *	seq,
		void *	seq_init_param,
		uint	n_ranges,
		uint *	bufsz,
		uint *	flags,
		Cost_estimate *	cost
	)

dsmrr_init()

int DsMrr_impl::dsmrr_init	(	RANGE_SEQ_IF *	seq_funcs,
		void *	seq_init_param,
		uint	n_ranges,
		uint	mode,
		HANDLER_BUFFER *	buf
	)

DS-MRR: Initialize and start MRR scan.

Initialize and start the MRR scan. Depending on the mode parameter, this may use default or DS-MRR implementation.

The DS-MRR implementation will use a second handler object (h2) for doing scan on the index:

• on the first call to this function the h2 handler will be created and h2 will be opened using the same index as the main handler is set to use. The index scan on the main index will be closed and it will be re-opened to read records from the table using either no key or the primary key. The h2 handler will be deleted when reset() is called (which should happen on the end of the statement).
• when dsmrr_close() is called the index scan on h2 is closed.
• on following calls to this function one of the following must be valid: a. if dsmrr_close has been called: the main handler (h) must be open on an index, h2 will be opened using this index, and the index on h will be closed and h will be re-opened to read reads from the table using either no key or the primary key. b. dsmrr_close has not been called: h2 will already be open, the main handler h must be set up to read records from the table (handler->inited is RND) either using the primary index or using no index at all.

Parameters

	seq_funcs	Interval sequence enumeration functions
	seq_init_param	Interval sequence enumeration parameter
	n_ranges	Number of ranges in the sequence.
	mode	HA_MRR_* modes to use
[in,out]	buf	Buffer to use

Return values

0	Ok, Scan started.
other	Error

dsmrr_next()

int DsMrr_impl::dsmrr_next

(

char **

range_info

)

get_disk_sweep_mrr_cost()

bool DsMrr_impl::get_disk_sweep_mrr_cost ( uint  keynr, ha_rows  rows, uint  flags, uint *  buffer_size, Cost_estimate *  cost  )

private

Get cost of DS-MRR scan.

Parameters

keynr	Index to be used
rows	E(Number of rows to be scanned)
flags	Scan parameters (HA_MRR_* flags)
buffer_size	INOUT Buffer size
cost	OUT The cost

Return values

false	OK
true	Error, DS-MRR cannot be used (the buffer is too small for even 1 rowid)

init()

void DsMrr_impl::init ( TABLE *  table_arg )

inline

Initialize the DsMrr_impl object.

This object is used for both doing default MRR scans and DS-MRR scans. This function just initializes the object. To do a DS-MRR scan, this must also be initialized by calling dsmrr_init().

Parameters

table_arg

pointer to the TABLE that owns the handler

reset()

void DsMrr_impl::reset

(

void

)

Resets the DS-MRR object to the state it had after being initialized.

If there is an open scan then it will be closed.

This function should be called by handler::ha_reset() which is called when a statement is completed in order to make the handler object ready for re-use by a different statement.

Member Data Documentation

dsmrr_eof

bool DsMrr_impl::dsmrr_eof

private

h

handler* const DsMrr_impl::h

private

h2

handler* DsMrr_impl::h2

private

is_mrr_assoc

bool DsMrr_impl::is_mrr_assoc

private

rowids_buf

uchar* DsMrr_impl::rowids_buf

private

rowids_buf_cur

uchar* DsMrr_impl::rowids_buf_cur

private

rowids_buf_end

uchar* DsMrr_impl::rowids_buf_end

private

rowids_buf_last

uchar* DsMrr_impl::rowids_buf_last

private

table

TABLE* DsMrr_impl::table

private

use_default_impl

bool DsMrr_impl::use_default_impl

private

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

• sql/handler.h
• sql/handler.cc