mirror/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-02-04 21:02:17 +01:00
Code Issues Projects Releases Packages Wiki Activity Actions
mariadb/mysql-test/suite/rpl/r/rpl_semisync_ali_issues.result
Michael Widenius 7af50e4df4 MDEV-32551: "Read semi-sync reply magic number error" warnings on master 
rpl_semi_sync_slave_enabled_consistent.test and the first part of
the commit message comes from Brandon Nesterenko.

A test to show how to induce the "Read semi-sync reply magic number
error" message on a primary. In short, if semi-sync is turned on
during the hand-shake process between a primary and replica, but
later a user negates the rpl_semi_sync_slave_enabled variable while
the replica's IO thread is running; if the io thread exits, the
replica can skip a necessary call to kill_connection() in
repl_semisync_slave.slave_stop() due to its reliance on a global
variable. Then, the replica will send a COM_QUIT packet to the
primary on an active semi-sync connection, causing the magic number
error.

The test in this patch exits the IO thread by forcing an error;
though note a call to STOP SLAVE could also do this, but it ends up
needing more synchronization. That is, the STOP SLAVE command also
tries to kill the VIO of the replica, which makes a race with the IO
thread to try and send the COM_QUIT before this happens (which would
need more debug_sync to get around). See THD::awake_no_mutex for
details as to the killing of the replica’s vio.

Notes:
- The MariaDB documentation does not make it clear that when one
  enables semi-sync replication it does not matter if one enables
  it first in the master or slave. Any order works.

Changes done:
- The rpl_semi_sync_slave_enabled variable is now a default value for
  when semisync is started. The variable does not anymore affect
  semisync if it is already running. This fixes the original reported
  bug.  Internally we now use repl_semisync_slave.get_slave_enabled()
  instead of rpl_semi_sync_slave_enabled. To check if semisync is
  active on should check the @@rpl_semi_sync_slave_status variable (as
  before).
- The semisync protocol conflicts in the way that the original
  MySQL/MariaDB client-server protocol was designed (client-server
  send and reply packets are strictly ordered and includes a packet
  number to allow one to check if a packet is lost). When using
  semi-sync the master and slave can send packets at 'any time', so
  packet numbering does not work. The 'solution' has been that each
  communication starts with packet number 1, but in some cases there
  is still a chance that the packet number check can fail.  Fixed by
  adding a flag (pkt_nr_can_be_reset) in the NET struct that one can
  use to signal that packet number checking should not be done. This
  is flag is set when semi-sync is used.
- Added Master_info::semi_sync_reply_enabled to allow one to configure
  some slaves with semisync and other other slaves without semisync.
  Removed global variable semi_sync_need_reply that would not work
  with multi-master.
- Repl_semi_sync_master::report_reply_packet() can now recognize
  the COM_QUIT packet from semisync slave and not give a
  "Read semi-sync reply magic number error" error for this case.
  The slave will be removed from the Ack listener.
- On Windows, don't stop semisync Ack listener just because one
  slave connection is using socket_id > FD_SETSIZE.
- Removed busy loop in Ack_receiver::run() by using
 "Self-pipe trick" to signal new slave and stop Ack_receiver.
- Changed some Repl_semi_sync_slave functions that always returns 0
  from int to void.
- Added Repl_semi_sync_slave::slave_reconnect().
- Removed dummy_function Repl_semi_sync_slave::reset_slave().
- Removed some duplicate semisync notes from the error log.
- Add test of "if (get_slave_enabled() && semi_sync_need_reply)"
  before calling Repl_semi_sync_slave::slave_reply().
  (Speeds up the code as we can skip all initializations).
- If epl_semisync_slave.slave_reply() fails, we disable semisync
  for that connection.
- We do not call semisync.switch_off() if there are no active slaves.
  Instead we check in Repl_semi_sync_master::commit_trx() if there are
  no active threads. This simplices the code.
- Changed assert() to DBUG_ASSERT() to ensure that the DBUG log is
  flushed in case of asserts.
- Removed the internal rpl_semi_sync_slave_status as it is not needed
  anymore. The @@rpl_semi_sync_slave_status status variable is now
  mapped to rpl_semi_sync_enabled.
- Removed rpl_semi_sync_slave_enabled  as it is not needed anymore.
  Repl_semi_sync_slave::get_slave_enabled() contains the active status.
- Added checking that we do not add a slave twice with
  Ack_receiver::add_slave(). This could happen with old code.
- Removed Repl_semi_sync_master::check_and_switch() as it is not
  needed anymore.
- Ensure that when we call Ack_receiver::remove_slave() that the slave
  is removed from the listener before function returns.
- Call listener.listen_on_sockets() outside of mutex for better
  performance and less contested mutex.
- Ensure that listening is ignoring newly added slaves when checking for
  responses.
- Fixed the master ack_receiver listener is not killed if there are no
  connected slaves (and thus stop semisync handling of future
  connections). This could happen if all slaves sockets where would be
  marked as unreliable.
- Added unlink() to base_ilist_iterator and remove() to
  I_List_iterator. This enables us to remove 'dead' slaves in
  Ack_recever::run().
- kill_zombie_dump_threads() now does killing of dump threads properly.
  - It can now kill several threads (should be impossible but could
    happen if IO slaves reconnects very fast).
  - We now wait until the dump thread is done before starting the
    dump.
- Added an error if kill_zombie_dump_threads() fails.
- Set thd->variables.server_id before calling
  kill_zombie_dump_threads(). This simplies the code.
- Added a lot of comments both in code and tests.
- Removed DBUG_EVALUATE_IF "failed_slave_start" as it is not used.

Test changes:
- rpl.rpl_session_var2 added which runs rpl.rpl_session_var test with
  semisync enabled.
- Some timings changed slight with startup of slave which caused
  rpl_binlog_dump_slave_gtid_state_info.text to fail as it checked the
  error log file before the slave had started properly. Fixed by
  adding wait_for_pattern_in_file.inc that allows waiting for the
  pattern to appear in the log file.
- Tests have been updated so that we first set
  rpl_semi_sync_master_enabled on the master and then set
  rpl_semi_sync_slave_enabled on the slaves (this is according to how
  the MariaDB documentation document how to setup semi-sync).
- Error text "Master server does not have semi-sync enabled" has been
  replaced with "Master server does not support semi-sync" for the
  case when the master supports semi-sync but semi-sync is not
  enabled.

Other things:
- Some trivial cleanups in Repl_semi_sync_master::update_sync_header().
- We should in 11.3 changed the default value for
  rpl-semi-sync-master-wait-no-slave from TRUE to FALSE as the TRUE
  does not make much sense as default. The main difference with using
  FALSE is that we do not wait for semisync Ack if there are no slave
  threads.  In the case of TRUE we wait once, which did not bring any
  notable benefits except slower startup of master configured for
  using semisync.

Co-author: Brandon Nesterenko <brandon.nesterenko@mariadb.com>

This solves the problem reported in MDEV-32960 where a new
slave may not be registered in time and the master disables
semi sync because of that.
2024-01-23 13:03:11 +02:00

348 lines
10 KiB
Text
Raw Permalink Blame History

include/master-slave.inc
[connection master]
CALL mtr.add_suppression("Failed to start semi-sync ACK receiver thread.*");
CALL mtr.add_suppression("Failed to register slave to semi-sync ACK receiver thread.*");
CALL mtr.add_suppression("Failed to stop ack receiver thread on pthread_join.*");
CALL mtr.add_suppression("Got an error reading communication packets:*");
CALL mtr.add_suppression("Timeout waiting for reply of binlog*");
CALL mtr.add_suppression("slave_read_sync_header*");
CALL mtr.add_suppression("Missing magic number for semi-sync*");
CALL mtr.add_suppression("Got timeout reading communication packets*");
CALL mtr.add_suppression("Failed to call*");
CALL mtr.add_suppression("Execution failed on master*");
CALL mtr.add_suppression("Failed on request_dump()*");
CALL mtr.add_suppression("Semi-sync master failed on*");
CALL mtr.add_suppression("Master command COM_BINLOG_DUMP failed*");
CALL mtr.add_suppression("on master failed*");
CALL mtr.add_suppression("Semi-sync slave net_flush*");
CALL mtr.add_suppression("Failed to flush master info*");
CALL mtr.add_suppression("Request to stop slave SQL Thread received while apply*");
connection master;
[ enable semi-sync on master ]
set global rpl_semi_sync_master_enabled = 1;
show variables like 'rpl_semi_sync_master_enabled';
Variable_name Value
rpl_semi_sync_master_enabled ON
connection slave;
[ enable semi-sync on slave ]
stop slave;
set global rpl_semi_sync_slave_enabled = 1;
start slave;
show status like 'rpl_semi_sync_slave%';
Variable_name Value
Rpl_semi_sync_slave_send_ack 0
Rpl_semi_sync_slave_status ON
connection master;
CREATE TABLE t1(a INT) ENGINE=InnoDB;
connection slave;
connection master;
connect con1,localhost,root,,;
connect con2,localhost,root,,;
connect con3,localhost,root,,;
show status like 'Rpl_semi_sync_master_clients';
Variable_name Value
Rpl_semi_sync_master_clients 1
show status like "rpl_semi_sync_master_yes_tx";
Variable_name Value
Rpl_semi_sync_master_yes_tx 1
#########################################
# Test rpl_semi_sync_master_wait_point #
#########################################
# Test after_sync and after_commit first.
#Test after_sync
connection con1;
SET GLOBAL rpl_semi_sync_master_timeout = 1000000;
SET GLOBAL rpl_semi_sync_master_wait_point= 'AFTER_SYNC';
SET DEBUG_SYNC= "commit_before_get_LOCK_commit_ordered SIGNAL after_sync_done WAIT_FOR end";
INSERT into t1 values (1);;
connection con2;
SET DEBUG_SYNC= "now WAIT_FOR after_sync_done";
connection slave;
#slave can see record (1) after sync slave with master
select * from t1;
a
1
connection con2;
#con2 shouldn't see record (1)
select * from t1;
a
SET DEBUG_SYNC= "now SIGNAL end";
connection con1;
connection con1;
select * from t1;
a
1
truncate table t1;
INSERT INTO t1 VALUES (100);
connection slave;
connection con1;
SET DEBUG_SYNC= 'reset';
SET DEBUG_SYNC= "commit_before_get_LOCK_log SIGNAL before_fetch_done WAIT_FOR more_queue";
INSERT into t1 VALUES (1);;
connection con2;
SET DEBUG_SYNC= "now WAIT_FOR before_fetch_done";
SET DEBUG_SYNC= "after_semisync_queue SIGNAL more_queue";
INSERT INTO t1 VALUES (2);
connection con1;
connection con1;
SET DEBUG_SYNC= 'reset';
SET DEBUG_SYNC= "commit_before_get_LOCK_log SIGNAL before_fetch_done WAIT_FOR disable_semisync";
INSERT into t1 VALUES (3);;
connection con2;
SET DEBUG_SYNC= "now WAIT_FOR before_fetch_done";
SET GLOBAL rpl_semi_sync_master_enabled= 0;
SET DEBUG_SYNC= "now SIGNAL disable_semisync";
connection con1;
SET GLOBAL rpl_semi_sync_master_enabled = 1;
show status like 'Rpl_semi_sync_master_clients';
Variable_name Value
Rpl_semi_sync_master_clients 1
#Test after_commit
connection con1;
SET GLOBAL rpl_semi_sync_master_wait_point= 'AFTER_COMMIT';
SET DEBUG_SYNC= "after_group_after_commit SIGNAL after_commit_done WAIT_FOR end";
INSERT into t1 values (4);;
connection con2;
SET DEBUG_SYNC= "now WAIT_FOR after_commit_done";
connection slave;
select * from t1;
a
100
1
2
3
4
connection con2;
select * from t1;
a
100
1
2
3
4
SET DEBUG_SYNC= "now SIGNAL end";
connection con1;
connection con1;
select * from t1;
a
100
1
2
3
4
truncate table t1;
#######################################################
# Test some other options in order to cover the patch #
#######################################################
connection slave;
# Test rpl_semi_sync_slave_trace_level
SET GLOBAL rpl_semi_sync_slave_trace_level= 1;
SET GLOBAL rpl_semi_sync_slave_trace_level= 16;
SET GLOBAL rpl_semi_sync_slave_trace_level= 64;
SET GLOBAL rpl_semi_sync_slave_trace_level= 128;
SET GLOBAL rpl_semi_sync_slave_trace_level= 32;
connection master;
# Test rpl_semi_sync_master_trace_level
SET GLOBAL rpl_semi_sync_master_trace_level= 1;
SET GLOBAL rpl_semi_sync_master_trace_level= 16;
SET GLOBAL rpl_semi_sync_master_trace_level= 64;
SET GLOBAL rpl_semi_sync_master_trace_level= 128;
SET GLOBAL rpl_semi_sync_master_trace_level= 32;
# Test rpl_semi_sync_master_timeout
SET GLOBAL rpl_semi_sync_master_timeout= 1000;
SET GLOBAL rpl_semi_sync_master_timeout= 10000;
SET GLOBAL rpl_semi_sync_master_timeout = 1000000;
# Test rpl_semi_sync_slave_kill_conn_timeout
SET GLOBAL rpl_semi_sync_slave_kill_conn_timeout= 10;
SET GLOBAL rpl_semi_sync_slave_kill_conn_timeout= 20;
SET GLOBAL rpl_semi_sync_slave_kill_conn_timeout= 60;
SET GLOBAL rpl_semi_sync_slave_kill_conn_timeout= 5;
############################################
# Test rpl_semi_sync_master_wait_no_slave #
############################################
SET GLOBAL rpl_semi_sync_master_wait_no_slave = 1;
connection slave;
STOP SLAVE IO_THREAD;
include/wait_for_slave_io_to_stop.inc
connection con1;
SET GLOBAL rpl_semi_sync_master_timeout = 1000;
INSERT INTO t1 values (1);;
connection con1;
# Rpl_semi_sync_master_no_tx should be non-zero
SHOW STATUS LIKE 'Rpl_semi_sync_master_no_tx'
connection slave;
START SLAVE IO_THREAD;
include/wait_for_slave_io_to_start.inc
connection con1;
INSERT INTO t1 values (2);
connection slave;
connection con1;
show status like 'Rpl_semi_sync_master_clients';
Variable_name Value
Rpl_semi_sync_master_clients 1
show status like 'Rpl_semi_sync_master_status';
Variable_name Value
Rpl_semi_sync_master_status ON
connection slave;
STOP SLAVE IO_THREAD;
include/wait_for_slave_io_to_stop.inc
connection con1;
SET GLOBAL rpl_semi_sync_master_wait_no_slave= 0;
SET GLOBAL rpl_semi_sync_master_timeout= 1000000000;
INSERT INTO t1 values (3);
show status like 'Rpl_semi_sync_master_clients';
Variable_name Value
Rpl_semi_sync_master_clients 0
show status like 'Rpl_semi_sync_master_status';
Variable_name Value
Rpl_semi_sync_master_status ON
connection slave;
START SLAVE IO_THREAD;
include/wait_for_slave_io_to_start.inc
connection con1;
SET GLOBAL rpl_semi_sync_master_timeout= 10000000;
SET GLOBAL rpl_semi_sync_master_wait_no_slave= 1;
INSERT INTO t1 values (4);
connection slave;
connection con1;
show status like 'Rpl_semi_sync_master_status';
Variable_name Value
Rpl_semi_sync_master_status ON
show status like 'Rpl_semi_sync_master_clients';
Variable_name Value
Rpl_semi_sync_master_clients 1
##########################################
# Test rpl_semi_sync_slave_delay_master #
##########################################
connection slave;
SET GLOBAL rpl_semi_sync_slave_delay_master= 1;
START SLAVE IO_THREAD;
Warnings:
Note 1254 Slave is already running
include/wait_for_slave_io_to_start.inc
connection con1;
INSERT INTO t1 values (3);
include/sync_slave_io_with_master.inc
connection con1;
show status like 'Rpl_semi_sync_master_clients';
Variable_name Value
Rpl_semi_sync_master_clients 1
show status like 'Rpl_semi_sync_master_status';
Variable_name Value
Rpl_semi_sync_master_status ON
connection slave;
connection slave;
select * from t1 order by a;
a
1
2
3
3
4
connection con1;
select * from t1 order by a;
a
1
2
3
3
4
connection slave;
SET GLOBAL rpl_semi_sync_slave_delay_master = 0;
STOP SLAVE IO_THREAD;
include/wait_for_slave_io_to_stop.inc
START SLAVE IO_THREAD;
include/wait_for_slave_io_to_start.inc
##########################################################
# Test rpl_semi_sync_master_enabled and new ACK thread #
#########################################################
connection con1;
SET GLOBAL rpl_semi_sync_master_enabled = 0;
show status like 'Rpl_semi_sync_master_clients';
Variable_name Value
Rpl_semi_sync_master_clients 1
INSERT INTO t1 VALUES (1);
SET GLOBAL rpl_semi_sync_master_enabled = 1;
INSERT INTO t1 VALUES (2);
show status like 'Rpl_semi_sync_master_clients';
Variable_name Value
Rpl_semi_sync_master_clients 1
# Test failure of select error .
SET GLOBAL debug = 'd,rpl_semisync_simulate_select_error';
INSERT INTO t1 VALUES(3);
connection slave;
connection con1;
# Test failure of pthread_create
SET GLOBAL rpl_semi_sync_master_enabled = 0;
SET GLOBAL debug = 'd,rpl_semisync_simulate_create_thread_failure';
SET GLOBAL rpl_semi_sync_master_enabled= ON;
# Test failure of pthread_join
SET GLOBAL rpl_semi_sync_master_enabled= OFF;
#
# Failure on registering semisync slave
#
SET GLOBAL debug= 'd,rpl_semisync_simulate_add_slave_failure';
SET GLOBAL rpl_semi_sync_master_enabled= ON;
connection slave;
STOP SLAVE IO_THREAD;
include/wait_for_slave_io_to_stop.inc
START SLAVE IO_THREAD;
include/wait_for_slave_io_to_start.inc
connection con1;
SET GLOBAL debug='';
connection slave;
START SLAVE IO_THREAD;
include/wait_for_slave_io_to_start.inc
connection con1;
connection slave;
show status like 'Rpl_semi_sync_master_clients';
Variable_name Value
Rpl_semi_sync_master_clients 0
##################################################################
# Test fixing of BUG#70669 #
#SLAVE CAN'T CONTINUE REPLICATION AFTER MASTER'S CRASH RECOVERY #
#################################################################
connection con1;
SET GLOBAL sync_binlog = 1;
CREATE TABLE t2 (c1 INT);
connection slave;
connection con1;
INSERT INTO t2 values (1);
connection slave;
connection con2;
connection con1;
connection slave;
show tables like 't2';
Tables_in_test (t2)
t2
select * from t2;
c1
1
connection con1;
INSERT INTO t2 VALUES (2);
connection con2;
INSERT INTO t2 VALUES (3);
connection con1;
connection con2;
connection con1;
SET GLOBAL sync_binlog = 0;
DROP TABLE t2;
connection con2;
connection slave;
show tables like 't2';
Tables_in_test (t2)
connection con2;
#cleanup
connection master;
SET DEBUG_SYNC= 'reset';
disconnect con1;
disconnect con2;
disconnect con3;
SET GLOBAL rpl_semi_sync_master_timeout= 10000;
SET GLOBAL rpl_semi_sync_master_enabled = 0;
DROP TABLE t1;
connection slave;
SET GLOBAL rpl_semi_sync_slave_enabled = 0;
stop slave;
start slave;
include/rpl_end.inc
Reference in a new issue View git blame Copy permalink