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Code Activity

MDEV-31404 Implement binlog_space_limit

Browse Source 
binlog_space_limit is a variable in Percona server used to limit the total
size of all binary logs.

This implementation is based on code from Percona server 5.7.

In MariaDB we decided to call the variable max-binlog-total-size to be
similar to max-binlog-size. This makes it easier to find in the output
from 'mariadbd --help --verbose'). MariaDB will also support
binlog_space_limit for compatibility with Percona.

Some internal notes to explain implementation notes:

- When running MariaDB does not delete binary logs that are either
  used by slaves or have active xid that are not yet committed.

Some implementation notes:

- max-binlog-total-size is by default 0 (no limit).
- max-binlog-total-size can be changed without server restart.
- Binlog file sizes are checked on startup, or if
  max-binlog-total-size is set to a value > 0, not for every log write.
  The total size of all binary logs is cached and dynamically updated
  when updating the binary log on binary log rotation.
- max-binlog-total-size is checked against existing log files during
  serverstart, binlog rotation, FLUSH LOGS, when writing to binary log
  or when max-binlog-total-size changes value.
- Option --slave-connections-needed-for-purge with 1 as default added.
  This allows one to ensure that we do not delete binary logs if there
  is less than 'slave-connections-needed-for-purge' connected.
  Without this option max-binlog-total-size would potentially delete
  binlogs needed by slaves on server startup or when a slave disconnects
  as there are then no connected slaves to protect active binlogs.
- PURGE BINARY LOGS TO ... will be executed as if
  slave-connectitons-needed-for-purge would be zero. In other words
  it will do the purge even if there is no slaves connected. If there
  are connected slaves working on the logs, these will be protected.
- If binary log is on and max-binlog-total_size <> 0 then the status
  variable 'Binlog_disk_use' shows the current size of all old binary
  logs + the state of the current one.
- Removed test of strcmp(log_file_name, log_info.log_file_name) in
  purge_logs_before_date() as this is tested in can_purge_logs()
- To avoid expensive calls of log_in_use() we cache the result for the
  last log that is in use by a slave. Future calls to can_purge_logs()
  for this binary log will be quickly detected and false will be returned
  until a slave starts working on a new log.
- Note that after a binary log rotation caused by max_binlog_size,
  the last log will not be purged directly as it is still in use
  internally. The next binary log write will purge binlogs if needed.

Reviewer:Kristian Nielsen <knielsen@knielsen-hq.org>
This commit is contained in:
Monty
2023-12-03 21:42:44 +02:00
committed by Sergei Golubchik
parent 9933a8cc88
commit 18dfcfdecf
23 changed files with 906 additions and 46 deletions
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123
mysql-test/suite/binlog/r/max_binlog_total_size.result Normal file
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select @@global.max_binlog_total_size;
@@global.max_binlog_total_size
1500
select @@global.max_binlog_size;
@@global.max_binlog_size
4096
#
# MDEV-31404 Implement binlog_space_limit
#
FLUSH LOGS;
FLUSH LOGS;
FLUSH LOGS;
show binary logs;
Log_name File_size
binary.000001 #
binary.000002 #
binary.000003 #
binary.000004 #
show status like "binlog_disk_use";
Variable_name Value
Binlog_disk_use 1552
set @@global.slave_connections_needed_for_purge= 0;
# binary.000001 should be deleted now
show binary logs;
Log_name File_size
binary.000002 #
binary.000003 #
binary.000004 #
show status like "binlog_disk_use";
Variable_name Value
Binlog_disk_use 1183
CREATE TABLE `t1` (
`v1` int(11) DEFAULT NULL,
`v2` varchar(8000) DEFAULT NULL,
KEY `v1` (`v1`)
) engine=myisam;
INSERT INTO t1 VALUES (0,repeat("a",3000));
show status like "binlog_disk_use";
Variable_name Value
Binlog_disk_use 3863
# First binary should be binary.000004
show binary logs;
Log_name File_size
binary.000004 #
INSERT INTO t1 VALUES (2,repeat("b",10));
# First binary should be binary.000004
show binary logs;
Log_name File_size
binary.000004 #
binary.000005 #
FLUSH LOGS;
# First binary should be binary.000005
show binary logs;
Log_name File_size
binary.000005 #
binary.000006 #
FLUSH LOGS;
FLUSH LOGS;
FLUSH LOGS;
FLUSH LOGS;
show binary logs;
Log_name File_size
binary.000008 #
binary.000009 #
binary.000010 #
show status like "binlog_disk_use";
Variable_name Value
Binlog_disk_use 1225
PURGE BINARY LOGS TO 'binary.000009';
# First binary should be binary.000009
show binary logs;
Log_name File_size
binary.000009 #
binary.000010 #
INSERT INTO t1 VALUES (3,repeat("c",4000));
# First binary should be binary.000010
show binary logs;
Log_name File_size
binary.000010 #
binary.000011 #
INSERT INTO t1 VALUES (4,repeat("d",3000));
# First binary should be binary.000011
show binary logs;
Log_name File_size
binary.000011 #
RESET MASTER;
show binary logs;
Log_name File_size
binary.000001 #
show status like "binlog_disk_use";
Variable_name Value
Binlog_disk_use 325
INSERT INTO t1 VALUES (5,"e");
FLUSH LOGS;
INSERT INTO t1 VALUES (6,repeat("f",3000));
show binary logs;
Log_name File_size
binary.000002 #
show status like "binlog_disk_use";
Variable_name Value
Binlog_disk_use 3647
INSERT INTO t1 VALUES (7,repeat("g",3000));
# binary.000001 should be deleted now
show binary logs;
Log_name File_size
binary.000002 #
binary.000003 #
show status like "binlog_disk_use";
Variable_name Value
Binlog_disk_use 7338
FLUSH LOGS;
FLUSH LOGS;
# binary.000002 should be deleted now
show binary logs;
Log_name File_size
binary.000003 423
binary.000004 423
binary.000005 379
show status like "binlog_disk_use";
Variable_name Value
Binlog_disk_use 1225
DROP TABLE IF EXISTS t1;
set @@global.slave_connections_needed_for_purge= default;