mariadb/mysql-test/suite/innodb/r/undo_space_dblwr.result
Marko Mäkelä 14685b10df MDEV-32050: Deprecate&ignore innodb_purge_rseg_truncate_frequency
The motivation of introducing the parameter
innodb_purge_rseg_truncate_frequency in
mysql/mysql-server@28bbd66ea5 and
mysql/mysql-server@8fc2120fed
seems to have been to avoid stalls due to freeing undo log pages
or truncating undo log tablespaces. In MariaDB Server,
innodb_undo_log_truncate=ON should be a much lighter operation
than in MySQL, because it will not involve any log checkpoint.

Another source of performance stalls should be
trx_purge_truncate_rseg_history(), which is shrinking the history list
by freeing the undo log pages whose undo records have been purged.
To alleviate that, we will introduce a purge_truncation_task that will
offload this from the purge_coordinator_task. In that way, the next
innodb_purge_batch_size pages may be parsed and purged while the pages
from the previous batch are being freed and the history list being shrunk.

The processing of innodb_undo_log_truncate=ON will still remain the
responsibility of the purge_coordinator_task.

purge_coordinator_state::count: Remove. We will ignore
innodb_purge_rseg_truncate_frequency, and act as if it had been
set to 1 (the maximum shrinking frequency).

purge_coordinator_state::do_purge(): Invoke an asynchronous task
purge_truncation_callback() to free the undo log pages.

purge_sys_t::iterator::free_history(): Free those undo log pages
that have been processed. This used to be a part of
trx_purge_truncate_history().

purge_sys_t::clone_end_view(): Take a new value of purge_sys.head
as a parameter, so that it will be updated while holding exclusive
purge_sys.latch. This is needed for race-free access to the field
in purge_truncation_callback().

Reviewed by: Vladislav Lesin
2023-10-25 09:11:58 +03:00

20 lines
739 B
Text

call mtr.add_suppression("Checksum mismatch in the first page of file");
show variables like 'innodb_doublewrite';
Variable_name Value
innodb_doublewrite ON
create table t1(f1 int not null, f2 int not null)engine=innodb;
insert into t1 values (1, 1);
InnoDB 0 transactions not purged
set GLOBAL innodb_log_checkpoint_now=1;
# Make the first page dirty for undo tablespace
set global innodb_saved_page_number_debug = 0;
set global innodb_fil_make_page_dirty_debug = 1;
SET GLOBAL innodb_max_dirty_pages_pct_lwm=0.0;
SET GLOBAL innodb_max_dirty_pages_pct=0.0;
# Kill the server
# restart
FOUND 1 /Checksum mismatch in the first page of file/ in mysqld.1.err
check table t1;
Table Op Msg_type Msg_text
test.t1 check status OK
drop table t1;