#include <read0read.h>
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 * | trx_ids |
| trx_id_t | creator_trx_id |
| ut_list_node< read_view_t > | view_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 |
VIEW_NORMAL, VIEW_HIGH_GRANULARITY
| 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:
- include/read0read.h
