row0purge.h File Reference

Purge obsolete records. More...

#include "univ.i"
#include "btr0pcur.h"
#include "btr0types.h"
#include "data0data.h"
#include "dict0types.h"
#include "que0types.h"
#include "row0types.h"
#include "trx0types.h"
#include "ut0vec.h"

Go to the source code of this file.

Classes
struct	Compare_page_free_tuple
struct	purge_node_t
struct	purge_node_t::rec_t
	Info required to purge a record. More...

Typedefs
using	Page_free_tuple = std::tuple< index_id_t, page_id_t, table_id_t >

Functions
purge_node_t *	row_purge_node_create (que_thr_t *parent, mem_heap_t *heap)
	Create a purge node to a query graph. More...
bool	row_purge_poss_sec (purge_node_t *node, dict_index_t *index, const dtuple_t *entry)
	Determines if it is possible to remove a secondary index entry. More...
que_thr_t *	row_purge_step (que_thr_t *thr)
	in: query thread More...

Detailed Description

Purge obsolete records.

Created 3/14/1997 Heikki Tuuri

Typedef Documentation

Page_free_tuple

using Page_free_tuple = std::tuple<index_id_t, page_id_t, table_id_t>

Function Documentation

row_purge_node_create()

purge_node_t * row_purge_node_create	(	que_thr_t *	parent,
		mem_heap_t *	heap
	)

Create a purge node to a query graph.

Parameters

[in]	parent	parent node, i.e., a thr node
[in]	heap	memory heap where created

Returns

own: purge node

row_purge_poss_sec()

bool row_purge_poss_sec	(	purge_node_t *	node,
		dict_index_t *	index,
		const dtuple_t *	entry
	)

Determines if it is possible to remove a secondary index entry.

Removal is possible if the secondary index entry does not refer to any not delete marked version of a clustered index record where DB_TRX_ID is newer than the purge view.

NOTE: This function should only be called by the purge thread, only while holding a latch on the leaf page of the secondary index entry (or keeping the buffer pool watch on the page). It is possible that this function first returns true and then false, if a user transaction inserts a record that the secondary index entry would refer to. However, in that case, the user transaction would also re-insert the secondary index entry after purge has removed it and released the leaf page latch.

Returns

true if the secondary index record can be purged in: secondary index entry

Removal is possible if the secondary index entry does not refer to any not delete marked version of a clustered index record where DB_TRX_ID is newer than the purge view.

NOTE: This function should only be called by the purge thread, only while holding a latch on the leaf page of the secondary index entry (or keeping the buffer pool watch on the page). It is possible that this function first returns true and then false, if a user transaction inserts a record that the secondary index entry would refer to. However, in that case, the user transaction would also re-insert the secondary index entry after purge has removed it and released the leaf page latch.

Returns

true if the secondary index record can be purged

Parameters

node	in/out: row purge node
index	in: secondary index
entry	in: secondary index entry

row_purge_step()

que_thr_t * row_purge_step

(

que_thr_t *

thr

)

in: query thread

in: query thread

This is a high-level function used in an SQL execution graph.

Parameters

[in,out]

thr

The query thread to execute

Returns

query thread to run next or nullptr