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mariadb/mysql-test/t/debug_sync.test
Dmitry Lenev afd15c43a9 Implement new type-of-operation-aware metadata locks. 
Add a wait-for graph based deadlock detector to the
MDL subsystem.

Fixes bug #46272 "MySQL 5.4.4, new MDL: unnecessary deadlock" and
bug #37346 "innodb does not detect deadlock between update and
alter table".

The first bug manifested itself as an unwarranted abort of a
transaction with ER_LOCK_DEADLOCK error by a concurrent ALTER
statement, when this transaction tried to repeat use of a
table, which it has already used in a similar fashion before
ALTER started.

The second bug showed up as a deadlock between table-level
locks and InnoDB row locks, which was "detected" only after
innodb_lock_wait_timeout timeout.

A transaction would start using the table and modify a few
rows.
Then ALTER TABLE would come in, and start copying rows
into a temporary table. Eventually it would stumble on
the modified records and get blocked on a row lock.
The first transaction would try to do more updates, and get
blocked on thr_lock.c lock.
This situation of circular wait would only get resolved
by a timeout.

Both these bugs stemmed from inadequate solutions to the
problem of deadlocks occurring between different
locking subsystems.

In the first case we tried to avoid deadlocks between metadata
locking and table-level locking subsystems, when upgrading shared
metadata lock to exclusive one.
Transactions holding the shared lock on the table and waiting for
some table-level lock used to be aborted too aggressively.

We also allowed ALTER TABLE to start in presence of transactions
that modify the subject table. ALTER TABLE acquires
TL_WRITE_ALLOW_READ lock at start, and that block all writes
against the table (naturally, we don't want any writes to be lost
when switching the old and the new table). TL_WRITE_ALLOW_READ
lock, in turn, would block the started transaction on thr_lock.c
lock, should they do more updates. This, again, lead to the need
to abort such transactions.

The second bug occurred simply because we didn't have any
mechanism to detect deadlocks between the table-level locks
in thr_lock.c and row-level locks in InnoDB, other than
innodb_lock_wait_timeout.

This patch solves both these problems by moving lock conflicts
which are causing these deadlocks into the metadata locking
subsystem, thus making it possible to avoid or detect such
deadlocks inside MDL.

To do this we introduce new type-of-operation-aware metadata
locks, which allow MDL subsystem to know not only the fact that
transaction has used or is going to use some object but also what
kind of operation it has carried out or going to carry out on the
object.

This, along with the addition of a special kind of upgradable
metadata lock, allows ALTER TABLE to wait until all
transactions which has updated the table to go away.
This solves the second issue.
Another special type of upgradable metadata lock is acquired
by LOCK TABLE WRITE. This second lock type allows to solve the
first issue, since abortion of table-level locks in event of
DDL under LOCK TABLES becomes also unnecessary.

Below follows the list of incompatible changes introduced by
this patch:

- From now on, ALTER TABLE and CREATE/DROP TRIGGER SQL (i.e. those
  statements that acquire TL_WRITE_ALLOW_READ lock)
  wait for all transactions which has *updated* the table to
  complete.

- From now on, LOCK TABLES ... WRITE, REPAIR/OPTIMIZE TABLE
  (i.e. all statements which acquire TL_WRITE table-level lock) wait
  for all transaction which *updated or read* from the table
  to complete.
  As a consequence, innodb_table_locks=0 option no longer applies
  to LOCK TABLES ... WRITE.

- DROP DATABASE, DROP TABLE, RENAME TABLE no longer abort
  statements or transactions which use tables being dropped or
  renamed, and instead wait for these transactions to complete.

- Since LOCK TABLES WRITE now takes a special metadata lock,
  not compatible with with reads or writes against the subject table
  and transaction-wide, thr_lock.c deadlock avoidance algorithm
  that used to ensure absence of deadlocks between LOCK TABLES
  WRITE and other statements is no longer sufficient, even for
  MyISAM. The wait-for graph based deadlock detector of MDL
  subsystem may sometimes be necessary and is involved. This may
  lead to ER_LOCK_DEADLOCK error produced for multi-statement
  transactions even if these only use MyISAM:

  session 1:         session 2:
  begin;

  update t1 ...      lock table t2 write, t1 write;
                     -- gets a lock on t2, blocks on t1

  update t2 ...
  (ER_LOCK_DEADLOCK)

- Finally,  support of LOW_PRIORITY option for LOCK TABLES ... WRITE
  was abandoned.
  LOCK TABLE ... LOW_PRIORITY WRITE from now on has the same
  priority as the usual LOCK TABLE ... WRITE.
  SELECT HIGH PRIORITY no longer trumps LOCK TABLE ... WRITE  in
  the wait queue.

- We do not take upgradable metadata locks on implicitly
  locked tables. So if one has, say, a view v1 that uses
  table t1, and issues:
  LOCK TABLE v1 WRITE;
  FLUSH TABLE t1; -- (or just 'FLUSH TABLES'),
  an error is produced.
  In order to be able to perform DDL on a table under LOCK TABLES,
  the table must be locked explicitly in the LOCK TABLES list.
2010-02-01 14:43:06 +03:00

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###################### t/debug_sync.test ###############################
# #
# Testing of the Debug Sync Facility. #
# #
# There is important documentation within sql/debug_sync.cc #
# #
# Used objects in this test case: #
# p0 - synchronization point 0. Non-existent dummy sync point. #
# s1 - signal 1. #
# s2 - signal 2. #
# #
# Creation: #
# 2008-02-18 istruewing #
# #
########################################################################
#
# We need the Debug Sync Facility.
#
--source include/have_debug_sync.inc
#
# We are checking privileges, which the embedded server cannot do.
#
--source include/not_embedded.inc
#
# Preparative cleanup.
#
--disable_warnings
SET DEBUG_SYNC= 'RESET';
DROP TABLE IF EXISTS t1;
--enable_warnings
#
# Show the special system variable.
# It shows ON or OFF depending on the command line option --debug-sync.
# The test case assumes it is ON (command line option present).
#
SHOW VARIABLES LIKE 'DEBUG_SYNC';
#
# Syntax. Valid forms.
#
SET DEBUG_SYNC='p0 SIGNAL s1 WAIT_FOR s2 TIMEOUT 6 EXECUTE 2 HIT_LIMIT 3';
SET DEBUG_SYNC='p0 SIGNAL s1 WAIT_FOR s2 TIMEOUT 6 EXECUTE 2';
SET DEBUG_SYNC='p0 SIGNAL s1 WAIT_FOR s2 TIMEOUT 6 HIT_LIMIT 3';
SET DEBUG_SYNC='p0 SIGNAL s1 WAIT_FOR s2 TIMEOUT 6';
SET DEBUG_SYNC='p0 SIGNAL s1 WAIT_FOR s2 EXECUTE 2 HIT_LIMIT 3';
SET DEBUG_SYNC='p0 SIGNAL s1 WAIT_FOR s2 EXECUTE 2';
SET DEBUG_SYNC='p0 SIGNAL s1 WAIT_FOR s2 HIT_LIMIT 3';
SET DEBUG_SYNC='p0 SIGNAL s1 WAIT_FOR s2';
SET DEBUG_SYNC='p0 SIGNAL s1 EXECUTE 2 HIT_LIMIT 3';
SET DEBUG_SYNC='p0 SIGNAL s1 EXECUTE 2';
SET DEBUG_SYNC='p0 SIGNAL s1 HIT_LIMIT 3';
SET DEBUG_SYNC='p0 SIGNAL s1';
SET DEBUG_SYNC='p0 WAIT_FOR s2 TIMEOUT 6 EXECUTE 2 HIT_LIMIT 3';
SET DEBUG_SYNC='p0 WAIT_FOR s2 TIMEOUT 6 EXECUTE 2';
SET DEBUG_SYNC='p0 WAIT_FOR s2 TIMEOUT 6 HIT_LIMIT 3';
SET DEBUG_SYNC='p0 WAIT_FOR s2 TIMEOUT 6';
SET DEBUG_SYNC='p0 WAIT_FOR s2 EXECUTE 2 HIT_LIMIT 3';
SET DEBUG_SYNC='p0 WAIT_FOR s2 EXECUTE 2';
SET DEBUG_SYNC='p0 WAIT_FOR s2 HIT_LIMIT 3';
SET DEBUG_SYNC='p0 WAIT_FOR s2';
SET DEBUG_SYNC='p0 HIT_LIMIT 3';
SET DEBUG_SYNC='p0 CLEAR';
SET DEBUG_SYNC='p0 TEST';
SET DEBUG_SYNC='RESET';
#
# Syntax. Valid forms. Lower case.
#
set debug_sync='p0 signal s1 wait_for s2 timeout 6 execute 2 hit_limit 3';
set debug_sync='p0 signal s1 wait_for s2 timeout 6 execute 2';
set debug_sync='p0 signal s1 wait_for s2 timeout 6 hit_limit 3';
set debug_sync='p0 signal s1 wait_for s2 timeout 6';
set debug_sync='p0 signal s1 wait_for s2 execute 2 hit_limit 3';
set debug_sync='p0 signal s1 wait_for s2 execute 2';
set debug_sync='p0 signal s1 wait_for s2 hit_limit 3';
set debug_sync='p0 signal s1 wait_for s2';
set debug_sync='p0 signal s1 execute 2 hit_limit 3';
set debug_sync='p0 signal s1 execute 2';
set debug_sync='p0 signal s1 hit_limit 3';
set debug_sync='p0 signal s1';
set debug_sync='p0 wait_for s2 timeout 6 execute 2 hit_limit 3';
set debug_sync='p0 wait_for s2 timeout 6 execute 2';
set debug_sync='p0 wait_for s2 timeout 6 hit_limit 3';
set debug_sync='p0 wait_for s2 timeout 6';
set debug_sync='p0 wait_for s2 execute 2 hit_limit 3';
set debug_sync='p0 wait_for s2 execute 2';
set debug_sync='p0 wait_for s2 hit_limit 3';
set debug_sync='p0 wait_for s2';
set debug_sync='p0 hit_limit 3';
set debug_sync='p0 clear';
set debug_sync='p0 test';
set debug_sync='reset';
#
# Syntax. Valid forms. Line wrap, leading, mid, trailing space.
#
SET DEBUG_SYNC='p0 SIGNAL s1 WAIT_FOR s2 TIMEOUT 6
EXECUTE 2 HIT_LIMIT 3';
SET DEBUG_SYNC=' p0 SIGNAL s1 WAIT_FOR s2';
SET DEBUG_SYNC='p0 SIGNAL s1 WAIT_FOR s2';
SET DEBUG_SYNC='p0 SIGNAL s1 WAIT_FOR s2 ';
SET DEBUG_SYNC=' p0 SIGNAL s1 WAIT_FOR s2 ';
SET DEBUG_SYNC=' p0 SIGNAL s1 WAIT_FOR s2 ';
#
# Syntax. Invalid forms.
#
--error ER_PARSE_ERROR
SET DEBUG_SYNC='';
--error ER_PARSE_ERROR
SET DEBUG_SYNC=' ';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 EXECUTE 2';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 TIMEOUT 6 EXECUTE 2';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 TIMEOUT 6';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 WAIT_FOR s2 SIGNAL s1';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 WAIT_FOR s2 SIGNAL s1 EXECUTE 2';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 WAIT_FOR s2 SIGNAL s1 TIMEOUT 6 EXECUTE 2';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 WAIT_FOR s2 SIGNAL s1 TIMEOUT 6';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 WAIT_FOR s2 TIMEOUT 6 SIGNAL s1 EXECUTE 2';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 WAIT_FOR s2 TIMEOUT 6 SIGNAL s1';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 TIMEOUT 6 WAIT_FOR s2 EXECUTE 2';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 TIMEOUT 6 WAIT_FOR s2';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 SIGNAL s1 TIMEOUT 6 EXECUTE 2';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 SIGNAL s1 TIMEOUT 6';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 EXECUTE 2 SIGNAL s1 TIMEOUT 6';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 TIMEOUT 6 SIGNAL s1';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 EXECUTE 2 TIMEOUT 6 SIGNAL s1';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 CLEAR HIT_LIMIT 3';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='CLEAR';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 CLEAR p0';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='TEST';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 TEST p0';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 RESET';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='RESET p0';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 RESET p0';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 SIGNAL ';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 WAIT_FOR ';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 SIGNAL s1 EXECUTE ';
#
# Syntax. Invalid keywords used.
#
--error ER_UNKNOWN_SYSTEM_VARIABLE
SET DEBUG_SYNCx='p0 SIGNAL s1 WAIT_FOR s2 TIMEOUT 6 EXECUTE 2 HIT_LIMIT 3';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 SIGNAx s1 WAIT_FOR s2 TIMEOUT 6 EXECUTE 2 HIT_LIMIT 3';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 SIGNAL s1 WAIT_FOx s2 TIMEOUT 6 EXECUTE 2 HIT_LIMIT 3';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 SIGNAL s1 WAIT_FOR s2 TIMEOUx 0 EXECUTE 2 HIT_LIMIT 3';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 SIGNAL s1 WAIT_FOR s2 TIMEOUT 6 EXECUTx 2 HIT_LIMIT 3';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 SIGNAL s1 WAIT_FOR s2 TIMEOUT 6 EXECUTE 2 HIT_LIMIx 3';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 CLEARx';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 TESTx';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='RESETx';
#
# Syntax. Invalid numbers. Decimal only.
#
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 WAIT_FOR s2 TIMEOUT 0x6 EXECUTE 2 HIT_LIMIT 3';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 WAIT_FOR s2 TIMEOUT 6 EXECUTE 0x2 HIT_LIMIT 3';
--error ER_PARSE_ERROR
SET DEBUG_SYNC='p0 WAIT_FOR s2 TIMEOUT 7 EXECUTE 2 HIT_LIMIT 0x3';
#
# Syntax. Invalid value type.
#
--error ER_WRONG_TYPE_FOR_VAR
SET DEBUG_SYNC= 7;
#
# Syntax. DEBUG_SYNC is a SESSION-only variable.
#
--error ER_LOCAL_VARIABLE
SET GLOBAL DEBUG_SYNC= 'p0 CLEAR';
#
# Syntax. The variable value does not need to be a string literal.
#
SET @myvar= 'now SIGNAL from_myvar';
SET DEBUG_SYNC= @myvar;
SHOW VARIABLES LIKE 'DEBUG_SYNC';
#
SET DEBUG_SYNC= LEFT('now SIGNAL from_function_cut_here', 24);
SHOW VARIABLES LIKE 'DEBUG_SYNC';
#
# Functional tests.
#
# NOTE: There is the special synchronization point 'now'. It is placed
# immediately after setting of the DEBUG_SYNC variable.
# So it is executed before the SET statement ends.
#
# NOTE: There is only one global signal (say "signal post" or "flag mast").
# A SIGNAL action writes its signal into it ("sets a flag").
# The signal persists until explicitly overwritten.
# To avoid confusion for later tests, it is recommended to clear
# the signal by signalling "empty" ("setting the 'empty' flag"):
# SET DEBUG_SYNC= 'now SIGNAL empty';
# Preferably you can reset the whole facility with:
# SET DEBUG_SYNC= 'RESET';
# The signal is then '' (really empty) which connot be done otherwise.
#
#
# Time out immediately. This gives just a warning.
#
SET DEBUG_SYNC= 'now SIGNAL something';
SHOW VARIABLES LIKE 'DEBUG_SYNC';
# Suppress warning number
--replace_column 2 ####
SET DEBUG_SYNC= 'now WAIT_FOR nothing TIMEOUT 0';
#
# If signal is present already, TIMEOUT 0 does not give a warning.
#
SET DEBUG_SYNC= 'now SIGNAL nothing';
SHOW VARIABLES LIKE 'DEBUG_SYNC';
SET DEBUG_SYNC= 'now WAIT_FOR nothing TIMEOUT 0';
#
# EXECUTE 0 is effectively a no-op.
#
SET DEBUG_SYNC= 'now SIGNAL something EXECUTE 0';
SHOW VARIABLES LIKE 'DEBUG_SYNC';
SET DEBUG_SYNC= 'now WAIT_FOR anotherthing TIMEOUT 0 EXECUTE 0';
#
# Run into HIT_LIMIT. This gives an error.
#
--error ER_DEBUG_SYNC_HIT_LIMIT
SET DEBUG_SYNC= 'now HIT_LIMIT 1';
#
# Many actions. Watch the array growing and shrinking in the debug trace:
# egrep 'query:|debug_sync_action:' mysql-test/var/log/master.trace
#
SET DEBUG_SYNC= 'RESET';
SHOW VARIABLES LIKE 'DEBUG_SYNC';
SET DEBUG_SYNC= 'p1abcd SIGNAL s1 EXECUTE 2';
SET DEBUG_SYNC= 'p2abc SIGNAL s2 EXECUTE 2';
SET DEBUG_SYNC= 'p9abcdef SIGNAL s9 EXECUTE 2';
SET DEBUG_SYNC= 'p4a SIGNAL s4 EXECUTE 2';
SET DEBUG_SYNC= 'p5abcde SIGNAL s5 EXECUTE 2';
SET DEBUG_SYNC= 'p6ab SIGNAL s6 EXECUTE 2';
SET DEBUG_SYNC= 'p7 SIGNAL s7 EXECUTE 2';
SET DEBUG_SYNC= 'p8abcdef SIGNAL s8 EXECUTE 2';
SET DEBUG_SYNC= 'p3abcdef SIGNAL s3 EXECUTE 2';
#
# Execute some actions to show they exist. Each sets a distinct signal.
#
SET DEBUG_SYNC= 'p4a TEST';
SHOW VARIABLES LIKE 'DEBUG_SYNC';
SET DEBUG_SYNC= 'p1abcd TEST';
SHOW VARIABLES LIKE 'DEBUG_SYNC';
SET DEBUG_SYNC= 'p7 TEST';
SHOW VARIABLES LIKE 'DEBUG_SYNC';
SET DEBUG_SYNC= 'p9abcdef TEST';
SHOW VARIABLES LIKE 'DEBUG_SYNC';
SET DEBUG_SYNC= 'p3abcdef TEST';
SHOW VARIABLES LIKE 'DEBUG_SYNC';
#
# Clear the actions.
#
SET DEBUG_SYNC= 'p1abcd CLEAR';
SET DEBUG_SYNC= 'p2abc CLEAR';
SET DEBUG_SYNC= 'p5abcde CLEAR';
SET DEBUG_SYNC= 'p6ab CLEAR';
SET DEBUG_SYNC= 'p8abcdef CLEAR';
SET DEBUG_SYNC= 'p9abcdef CLEAR';
SET DEBUG_SYNC= 'p3abcdef CLEAR';
SET DEBUG_SYNC= 'p4a CLEAR';
SET DEBUG_SYNC= 'p7 CLEAR';
#
# Execute some actions to show they have gone.
#
SET DEBUG_SYNC= 'p1abcd TEST';
SHOW VARIABLES LIKE 'DEBUG_SYNC';
SET DEBUG_SYNC= 'p7 TEST';
SHOW VARIABLES LIKE 'DEBUG_SYNC';
SET DEBUG_SYNC= 'p9abcdef TEST';
SHOW VARIABLES LIKE 'DEBUG_SYNC';
#
# Now cleanup. Actions are clear already, but signal needs to be cleared.
#
SET DEBUG_SYNC= 'RESET';
SHOW VARIABLES LIKE 'DEBUG_SYNC';
#
# Facility requires SUPER privilege.
#
CREATE USER mysqltest_1@localhost;
GRANT SUPER ON *.* TO mysqltest_1@localhost;
--echo connection con1, mysqltest_1
connect (con1,localhost,mysqltest_1,,);
SET DEBUG_SYNC= 'RESET';
disconnect con1;
--echo connection default
connection default;
DROP USER mysqltest_1@localhost;
#
CREATE USER mysqltest_2@localhost;
GRANT ALL ON *.* TO mysqltest_2@localhost;
REVOKE SUPER ON *.* FROM mysqltest_2@localhost;
--echo connection con1, mysqltest_2
connect (con1,localhost,mysqltest_2,,);
--error ER_SPECIFIC_ACCESS_DENIED_ERROR
SET DEBUG_SYNC= 'RESET';
disconnect con1;
--echo connection default
connection default;
DROP USER mysqltest_2@localhost;
#
# Example 1.
#
# Preparative cleanup.
--disable_warnings
SET DEBUG_SYNC= 'RESET';
DROP TABLE IF EXISTS t1;
--enable_warnings
#
# Test.
CREATE TABLE t1 (c1 INT);
--echo connection con1
connect (con1,localhost,root,,);
SET DEBUG_SYNC= 'before_lock_tables_takes_lock
SIGNAL opened WAIT_FOR flushed';
send INSERT INTO t1 VALUES(1);
--echo connection default
connection default;
SET DEBUG_SYNC= 'now WAIT_FOR opened';
SET DEBUG_SYNC= 'after_flush_unlock SIGNAL flushed';
FLUSH TABLE t1;
--echo connection con1
connection con1;
reap;
disconnect con1;
--echo connection default
connection default;
DROP TABLE t1;
#
# Example 2.
#
# Preparative cleanup.
--disable_warnings
SET DEBUG_SYNC= 'RESET';
DROP TABLE IF EXISTS t1;
--enable_warnings
#
# Test.
CREATE TABLE t1 (c1 INT);
LOCK TABLE t1 READ;
--echo connection con1
connect (con1,localhost,root,,);
# Retain action after use. First used by general_log.
SET DEBUG_SYNC= 'wait_for_lock SIGNAL locked EXECUTE 2';
send INSERT INTO t1 VALUES (1);
--echo connection default
connection default;
# Wait until INSERT waits for lock.
SET DEBUG_SYNC= 'now WAIT_FOR locked';
# let INSERT continue.
UNLOCK TABLES;
--echo connection con1
connection con1;
--echo retrieve INSERT result.
reap;
disconnect con1;
--echo connection default
connection default;
DROP TABLE t1;
#
# Cleanup after test case.
# Otherwise signal would contain 'flushed' here,
# which could confuse the next test.
#
SET DEBUG_SYNC= 'RESET';
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