MDEV-31749 sporadic assert in MDEV-30619 new test
If the workers of a parallel replica are busy (potentially with long
queues), but the SQL thread has no events left to distribute (so it
goes idle), then the next event that comes from the primary will
update mi->last_master_timestamp with its timestamp, even if the
workers have not yet finished.
This patch changes the parallel replica logic which updates
last_master_timestamp after idling from using solely sql_thread_caught_up
(added in MDEV-29639) to using the latter with rli queued/dequeued
event counters.
That is, if the queued count is equal to the dequeued count, it
means all events have been processed and the replica is considered
idle when the driver thread has also distributed all events.
Low level details of the commit include
- to make a more generalized test for Seconds_Behind_Master on
the parallel replica, rpl_delayed_parallel_slave_sbm.test
is renamed to rpl_parallel_sbm.test for this purpose.
- pause_sql_thread_on_next_event usage was removed
with the MDEV-30619 fixes. Rather than remove it, we adapt it
to the needs of this test case
- added test case to cover SBM spike of relay log read and LMT
update that was fixed by MDEV-29639
- rpl_seconds_behind_master_spike.test is made to use
the negate_clock_diff_with_master debug eval.
Reviewed By:
============
Andrei Elkin <andrei.elkin@mariadb.com>
When using binlog_row_image=FULL with sequence table inserts, a
replica can deadlock because it treats full inserts in a sequence as DDL
statements by getting an exclusive lock on the sequence table. It
has been observed that with parallel replication, this exclusive
lock on the sequence table can lead to a deadlock where one
transaction has the exclusive lock and is waiting on a prior
transaction to commit, whereas this prior transaction is waiting on
the MDL lock.
This fix for this is on the master side, to raise FL_DDL
flag on the GTID of a full binlog_row_image write of a sequence table.
This forces the slave to execute the statement serially so a deadlock
cannot happen.
A test verifies the deadlock also to prove it happen on the OLD (pre-fixes)
slave.
OLD (buggy master) -replication-> NEW (fixed slave) is provided.
As the pre-fixes master's full row-image may represent both
SELECT NEXT VALUE and INSERT, the parallel slave pessimistically
waits for the prior transaction to have committed before to take on the
critical part of the second (like INSERT in the test) event execution.
The waiting exploits a parallel slave's retry mechanism which is
controlled by `@@global.slave_transaction_retries`.
Note that in order to avoid any persistent 'Deadlock found' 2013 error
in OLD -> NEW, `slave_transaction_retries` may need to be set to a
higher than the default value.
START-SLAVE is an effective work-around if this still happens.
handle_slave_io(), handle_slave_sql(), os_thread_exit():
Remove a redundant pthread_exit(nullptr) call, because it
would cause SIGSEGV.
mysql_print_status(): Add MEM_MAKE_DEFINED() to work around
some missing instrumentation around mallinfo2().
que_graph_free_stat_list(): Invoke que_node_get_next(node) before
que_graph_free_recursive(node). That is the logical and
MSAN_OPTIONS=poison_in_dtor=1 compatible way of freeing memory.
ins_node_t::~ins_node_t(): Invoke mem_heap_free(entry_sys_heap).
que_graph_free_recursive(): Rely on ins_node_t::~ins_node_t().
fts_t::~fts_t(): Invoke mem_heap_free(fts_heap).
fts_free(): Replace with direct calls to fts_t::~fts_t().
The failures in free_root() due to MSAN_OPTIONS=poison_in_dtor=1
will be covered in MDEV-30942.
One of the constraints added in the MDEV-29639 patch, is that only
the first event after idling should update last_master_timestamp;
and as long as the replica has more events to execute, the variable
should not be updated. The corresponding test,
rpl_delayed_parallel_slave_sbm.test, aims to verify this; however,
if the IO thread takes too long to queue events, the SQL thread can
appear to catch up too fast.
This fix ensures that the relay log has been fully written before
executing the events.
Note that the underlying cause of this test failure needs to be
addressed as a bug-fix, this is a temporary fix to stop test
failures. To track work on the bug-fix for the underlying issue,
please see MDEV-30619.
Problem
========
On a parallel, delayed replica, Seconds_Behind_Master will not be
calculated until after MASTER_DELAY seconds have passed and the
event has finished executing, resulting in potentially very large
values of Seconds_Behind_Master (which could be much larger than the
MASTER_DELAY parameter) for the entire duration the event is
delayed. This contradicts the documented MASTER_DELAY behavior,
which specifies how many seconds to withhold replicated events from
execution.
Solution
========
After a parallel replica idles, the first event after idling should
immediately update last_master_timestamp with the time that it began
execution on the primary.
Reviewed By
===========
Andrei Elkin <andrei.elkin@mariadb.com>
This patch adds the correct setting of the "--tls-version" and
"--ssl-verify-server-cert" options in the client-side utilities
such as mysqltest, mysqlcheck and mysqlslap, as well as the correct
setting of the "--ssl-crl" option when executing queries on the
slave side, and also the correct option codes in the "sslopts-logopts.h"
file (in the latter case, incorrect values are not a problem right
now, but may cause subtle test failures in the future, if the option
handling code changes).
This patch adds the correct setting of the "--ssl-verify-server-cert"
option in the client-side utilities such as mysqlcheck and mysqlslap,
as well as the correct setting of the "--ssl-crl" option when executing
queries on the slave side, and also add the correct option codes in
the "sslopts-logopts.h" file (in the latter case, incorrect values
are not a problem right now, but may cause subtle test failures in
the future, if the option handling code changes).
There are separate flags DBUG_OFF for disabling the DBUG facility
and ENABLED_DEBUG_SYNC for enabling the DEBUG_SYNC facility.
Let us allow debug builds without DEBUG_SYNC.
Note: For CMAKE_BUILD_TYPE=Debug, CMakeLists.txt will continue to
define ENABLED_DEBUG_SYNC.
In commit 28325b0863
a compile-time option was introduced to disable the macros
DBUG_ENTER and DBUG_RETURN or DBUG_VOID_RETURN.
The parameter name WITH_DBUG_TRACE would hint that it also
covers DBUG_PRINT statements. Let us do that: WITH_DBUG_TRACE=OFF
shall disable DBUG_PRINT() as well.
A few InnoDB recovery tests used to check that some output from
DBUG_PRINT("ib_log", ...) is present. We can live without those checks.
Reviewed by: Vladislav Vaintroub
