InnoDB Plugin  1.0
Data Fields
read_view_t Struct Reference

#include <read0read.h>

Collaboration diagram for read_view_t:
Collaboration graph

Data Fields

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 creator_trx_id
ut_list_node< read_view_tview_list

Detailed Description

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

read should not see the modifications to the database.

Field Documentation

trx_id_t read_view_t::creator_trx_id

trx id of creating transaction, or 0 used in purge

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".

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

ulint read_view_t::n_trx_ids

Number of cells in the trx_ids array

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.

ulint read_view_t::type


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

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".

ut_list_node< read_view_t > read_view_t::view_list

List of read views in trx_sys

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