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Public Member Functions | Public Attributes | List of all members
read_view_t Struct Reference

#include <read0read.h>

Public Member Functions

 UT_LIST_NODE_T (read_view_t) view_list

Public Attributes

ulint type
undo_no_t undo_no
trx_id_t low_limit_no
trx_id_t low_limit_id
trx_id_t up_limit_id
ulint n_trx_ids
trx_id_t * trx_ids
trx_id_t creator_trx_id

Detailed Description

Read view lists the trx ids of those transactions for which a consistent

read should not see the modifications to the database.

Definition at line 125 of file read0read.h.

Member Function Documentation

read_view_t::UT_LIST_NODE_T ( read_view_t  )

List of read views in trx_sys

Member Data Documentation

trx_id_t read_view_t::creator_trx_id

trx id of creating transaction, or 0 used in purge

Definition at line 157 of file read0read.h.

trx_id_t read_view_t::low_limit_id

The read should not see any transaction with trx id >= this value. In other words, this is the "high water mark".

Definition at line 138 of file read0read.h.

trx_id_t read_view_t::low_limit_no

The view does not need to see the undo logs for transactions whose transaction number is strictly smaller (<) than this value: they can be removed in purge if not needed by other views

Definition at line 132 of file read0read.h.

ulint read_view_t::n_trx_ids

Number of cells in the trx_ids array

Definition at line 147 of file read0read.h.

trx_id_t* read_view_t::trx_ids

Additional trx ids which the read should not see: typically, these are the read-write active transactions at the time when the read is serialized, except the reading transaction itself; the trx ids in this array are in a descending order. These trx_ids should be between the "low" and "high" water marks, that is, up_limit_id and low_limit_id.

Definition at line 148 of file read0read.h.

ulint read_view_t::type

VIEW_NORMAL, VIEW_HIGH_GRANULARITY

Definition at line 126 of file read0read.h.

undo_no_t read_view_t::undo_no

0 or if type is VIEW_HIGH_GRANULARITY transaction undo_no when this high-granularity consistent read view was created

Definition at line 127 of file read0read.h.

trx_id_t read_view_t::up_limit_id

The read should see all trx ids which are strictly smaller (<) than this value. In other words, this is the "low water mark".

Definition at line 142 of file read0read.h.

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