UUID vx review by yura (is_xxx() functions) #2
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Use constants instead of macros.
is_uuid_vx(), is_nil_uuid_vx(), is_max_uuid_vx() now return NULL on NULL argument. Added explicit cast to 'std::underlying_type_t<>' for 'boost::uuids::uuid' enums. Fixed problem with 'is_max_uuid_vx()' returning inverse results. 'is_max_uuid_vx()' reworked - we now compare with static 'max_uuid' constant. 'uuid_v1()' marked as a function that cannot return NULL.
lukin-oleksiy
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…nt on Windows and posix [#2] The posix version of NdbProcess::start_process assumed the arguments where quoted using " and \ in a way that resembles POSIX sh quoting, and unquoted spaces were treated as argument separators splitting the argument to several. But the Windows version of NdbProcess::start_process did not treat options in the same way. And the Windows C runtime (CRT) parse arguments different from POSIX sh. Note that if program do not use CRT when it may treat the command line in its own way and the quoting done for CRT will mess up the command line. On Windows NdbProcess:start_process should only be used for CRT compatible programs on Windows with respect to argument quoting on command line, or one should make sure given arguments will not trigger unwanted quoting. This may be relevant for ndb_sign_keys and --CA-tool=<batch-file>. Instead this patch change the intention of start_process to pass arguments without modification from caller to the called C programs argument vector in its main entry function. In posix path that is easy, just pass the incoming C strings to execvp. On Windows one need to quote for Windows CRT when composing the command line. Note that the command part of command line have different quoting than the following arguments have. Change-Id: I763530c634d3ea460b24e6e01061bbb5f3321ad4
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Problem: Starting ´ndb_mgmd --bind-address´ may potentially cause abnormal program termination in MgmtSrvr destructor when ndb_mgmd restart itself. Core was generated by `ndb_mgmd --defa'. Program terminated with signal SIGABRT, Aborted. #0 0x00007f8ce4066b8f in raise () from /lib64/libc.so.6 #1 0x00007f8ce4039ea5 in abort () from /lib64/libc.so.6 #2 0x00007f8ce40a7d97 in __libc_message () from /lib64/libc.so.6 #3 0x00007f8ce40af08c in malloc_printerr () from /lib64/libc.so.6 #4 0x00007f8ce40b132d in _int_free () from /lib64/libc.so.6 #5 0x00000000006e9ffe in MgmtSrvr::~MgmtSrvr (this=0x28de4b0) at mysql/8.0/storage/ndb/src/mgmsrv/MgmtSrvr.cpp: 890 percona#6 0x00000000006ea09e in MgmtSrvr::~MgmtSrvr (this=0x2) at mysql/8.0/ storage/ndb/src/mgmsrv/MgmtSrvr.cpp:849 percona#7 0x0000000000700d94 in mgmd_run () at mysql/8.0/storage/ndb/src/mgmsrv/main.cpp:260 percona#8 0x0000000000700775 in mgmd_main (argc=<optimized out>, argv=0x28041d0) at mysql/8.0/storage/ndb/src/ mgmsrv/main.cpp:479 Analysis: While starting up, the ndb_mgmd will allocate memory for bind_address in order to potentially rewrite the parameter. When ndb_mgmd restart itself the memory will be released and dangling pointer causing double free. Fix: Drop support for bind_address=[::], it is not documented anywhere, is not useful and doesn't work. This means the need to rewrite bind_address is gone and bind_address argument need neither alloc or free. Change-Id: I7797109b9d8391394587188d64d4b1f398887e94
lukin-oleksiy
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Jul 15, 2024
https://perconadev.atlassian.net/browse/PS-9222 Problem ======= When writing to the redo log, an issue of column order change not being recorded with INSTANT DDL was fixed by checking if the fields are also reordered, then adding the columns into the list. However when calculating the size of the buffer this fix doesn't take account the extra fields that may be logged, and causing the assertion on the buffer size failed eventually. Solution ======== To calculate the buffer size correctly, we move the logic of finding reordered fiedls before buffer size calculation, then count the number of fields with the same logic when deciding if a field needs to be logged.
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Upstream commit ID : fb-mysql-5.6.35/8cb1dc836b68f1f13e8b2655b2b8cb2d57f400b3 PS-5217 : Merge fb-prod201803 Summary: Original report: https://jira.mariadb.org/browse/MDEV-15816 To reproduce this bug just following below steps, client 1: USE test; CREATE TABLE t1 (i INT) ENGINE=MyISAM; HANDLER t1 OPEN h; CREATE TABLE t2 (i INT) ENGINE=RocksDB; LOCK TABLES t2 WRITE; client 2: FLUSH TABLES WITH READ LOCK; client 1: INSERT INTO t2 VALUES (1); So client 1 acquired the lock and set m_lock_rows = RDB_LOCK_WRITE. Then client 2 calls store_lock(TL_IGNORE) and m_lock_rows was wrongly set to RDB_LOCK_NONE, as below ``` #0 myrocks::ha_rocksdb::store_lock (this=0x7fffbc03c7c8, thd=0x7fffc0000ba0, to=0x7fffc0011220, lock_type=TL_IGNORE) #1 get_lock_data (thd=0x7fffc0000ba0, table_ptr=0x7fffe84b7d20, count=1, flags=2) #2 mysql_lock_abort_for_thread (thd=0x7fffc0000ba0, table=0x7fffbc03bbc0) #3 THD::notify_shared_lock (this=0x7fffc0000ba0, ctx_in_use=0x7fffbc000bd8, needs_thr_lock_abort=true) #4 MDL_lock::notify_conflicting_locks (this=0x555557a82380, ctx=0x7fffc0000cc8) #5 MDL_context::acquire_lock (this=0x7fffc0000cc8, mdl_request=0x7fffe84b8350, lock_wait_timeout=2) percona#6 Global_read_lock::lock_global_read_lock (this=0x7fffc0003fe0, thd=0x7fffc0000ba0) ``` Finally, client 1 "INSERT INTO..." hits the Assertion 'm_lock_rows == RDB_LOCK_WRITE' failed in myrocks::ha_rocksdb::write_row() Fix this bug by not setting m_locks_rows if lock_type == TL_IGNORE. Closes facebook/mysql-5.6#838 Pull Request resolved: facebook/mysql-5.6#871 Differential Revision: D9417382 Pulled By: lth fbshipit-source-id: c36c164e06c
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Upstream commit ID : fb-mysql-5.6.35/911d1a387a0d80f3ba52b7432c1abdbd7e8cb220 PS-6867 : Merge fb-prod201905 Summary: Missed a few in earlier fixes for AutoInitCopy rule. Also added a few fixes for anoymous class rule and local shadowing rule. Reviewed By: luqun Differential Revision: D15467213 fbshipit-source-id: 9325852dbdd
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PS-5741: Incorrect use of memset_s in keyring_vault.
Fixed the usage of memset_s. The arguments should be:
void memset_s(void *dest, size_t dest_max, int c, size_t n)
where the 2nd argument is size of buffer and the 3rd is
argument is character to fill.
---------------------------------------------------------------------------
PS-7769 - Fix use-after-return error in audit_log_exclude_accounts_validate
---
*Problem:*
`st_mysql_value::val_str` might return a pointer to `buf` which after
the function called is deleted. Therefore the value in `save`, after
reuturnin from the function, is invalid.
In this particular case, the error is not manifesting as val_str`
returns memory allocated with `thd_strmake` and it does not use `buf`.
*Solution:*
Allocate memory with `thd_strmake` so the memory in `save` is not local.
---------------------------------------------------------------------------
Fix test main.bug12969156 when WITH_ASAN=ON
*Problem:*
ASAN complains about stack-buffer-overflow on function `mysql_heartbeat`:
```
==90890==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7fe746d06d14 at pc 0x7fe760f5b017 bp 0x7fe746d06cd0 sp 0x7fe746d06478
WRITE of size 24 at 0x7fe746d06d14 thread T16777215
Address 0x7fe746d06d14 is located in stack of thread T26 at offset 340 in frame
#0 0x7fe746d0a55c in mysql_heartbeat(void*) /home/yura/ws/percona-server/plugin/daemon_example/daemon_example.cc:62
This frame has 4 object(s):
[48, 56) 'result' (line 66)
[80, 112) '_db_stack_frame_' (line 63)
[144, 200) 'tm_tmp' (line 67)
[240, 340) 'buffer' (line 65) <== Memory access at offset 340 overflows this variable
HINT: this may be a false positive if your program uses some custom stack unwind mechanism, swapcontext or vfork
(longjmp and C++ exceptions *are* supported)
Thread T26 created by T25 here:
#0 0x7fe760f5f6d5 in __interceptor_pthread_create ../../../../src/libsanitizer/asan/asan_interceptors.cpp:216
#1 0x557ccbbcb857 in my_thread_create /home/yura/ws/percona-server/mysys/my_thread.c:104
#2 0x7fe746d0b21a in daemon_example_plugin_init /home/yura/ws/percona-server/plugin/daemon_example/daemon_example.cc:148
#3 0x557ccb4c69c7 in plugin_initialize /home/yura/ws/percona-server/sql/sql_plugin.cc:1279
#4 0x557ccb4d19cd in mysql_install_plugin /home/yura/ws/percona-server/sql/sql_plugin.cc:2279
#5 0x557ccb4d218f in Sql_cmd_install_plugin::execute(THD*) /home/yura/ws/percona-server/sql/sql_plugin.cc:4664
percona#6 0x557ccb47695e in mysql_execute_command(THD*, bool) /home/yura/ws/percona-server/sql/sql_parse.cc:5160
percona#7 0x557ccb47977c in mysql_parse(THD*, Parser_state*, bool) /home/yura/ws/percona-server/sql/sql_parse.cc:5952
percona#8 0x557ccb47b6c2 in dispatch_command(THD*, COM_DATA const*, enum_server_command) /home/yura/ws/percona-server/sql/sql_parse.cc:1544
percona#9 0x557ccb47de1d in do_command(THD*) /home/yura/ws/percona-server/sql/sql_parse.cc:1065
percona#10 0x557ccb6ac294 in handle_connection /home/yura/ws/percona-server/sql/conn_handler/connection_handler_per_thread.cc:325
percona#11 0x557ccbbfabb0 in pfs_spawn_thread /home/yura/ws/percona-server/storage/perfschema/pfs.cc:2198
percona#12 0x7fe760ab544f in start_thread nptl/pthread_create.c:473
```
The reason is that `my_thread_cancel` is used to finish the daemon thread. This is not and orderly way of finishing the thread. ASAN does not register the stack variables are not used anymore which generates the error above.
This is a benign error as all the variables are on the stack.
*Solution*:
Finish the thread in orderly way by using a signalling variable.
---------------------------------------------------------------------------
PS-8204: Fix XML escape rules for audit plugin
https://jira.percona.com/browse/PS-8204
There was a wrong length specified for some XML
escape rules. As a result of this terminating null symbol from
replacement rule was copied into resulting string. This lead to
quer text truncation in audit log file.
In addition added empty replacement rules for '\b' and 'f' symbols
which just remove them from resulting string. These symboles are
not supported in XML 1.0.
---------------------------------------------------------------------------
PS-8854: Add main.percona_udf MTR test
Add a test to check FNV1A_64, FNV_64, and MURMUR_HASH user-defined functions.
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…n read() syscall over network https://jira.percona.com/browse/PS-8592 Description ----------- GR suffered from problems caused by the security probes and network scanner processes connecting to the group replication communication port. This usually is not a problem, but poses a serious threat when another member tries to join the cluster by initialting a connection to the member which is affected by external processes using the port dedicated for group communication for longer durations. On such activites by external processes, the SSL enabled server stalled forever on the SSL_accept() call waiting for handshake data. Below is the stacktrace: Thread 55 (Thread 0x7f7bb77ff700 (LWP 2198598)): #0 in read () #1 in sock_read () #2 in BIO_read () #3 in ssl23_read_bytes () #4 in ssl23_get_client_hello () #5 in ssl23_accept () percona#6 in xcom_tcp_server_startup(Xcom_network_provider*) () When the server stalled in the above path forever, it prohibited other members to join the cluster resulting in the following messages on the joiner server's logs. [ERROR] [MY-011640] [Repl] Plugin group_replication reported: 'Timeout on wait for view after joining group' [ERROR] [MY-011735] [Repl] Plugin group_replication reported: '[GCS] The member is already leaving or joining a group.' Solution -------- This patch adds two new variables 1. group_replication_xcom_ssl_socket_timeout It is a file-descriptor level timeout in seconds for both accept() and SSL_accept() calls when group replication is listening on the xcom port. When set to a valid value, say for example 5 seconds, both accept() and SSL_accept() return after 5 seconds. The default value has been set to 0 (waits infinitely) for backward compatibility. This variable is effective only when GR is configred with SSL. 2. group_replication_xcom_ssl_accept_retries It defines the number of retries to be performed before closing the socket. For each retry the server thread calls SSL_accept() with timeout defined by the group_replication_xcom_ssl_socket_timeout for the SSL handshake process once the connection has been accepted by the first accept() call. The default value has been set to 10. This variable is effective only when GR is configred with SSL. Note: - Both of the above variables are dynamically configurable, but will become effective only on START GROUP_REPLICATION. ------------------------------------------------------------------------------- PS-8844: Fix the failing main.mysqldump_gtid_purged https://jira.percona.com/browse/PS-8844 This patch fixes the test failure of main.mysqldump_gtid_purged that failed due to the uninitialized variable $redirect_stderr in the start_proc_in_background.inc.
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…ocal DDL
executed
https://perconadev.atlassian.net/browse/PS-9018
Problem
-------
In high concurrency scenarios, MySQL replica can enter into a deadlock due to a
race condition between the replica applier thread and the client thread
performing a binlog group commit.
Analysis
--------
It needs at least 3 threads for this deadlock to happen
1. One client thread
2. Two replica applier threads
How this deadlock happens?
--------------------------
0. Binlog is enabled on replica, but log_replica_updates is disabled.
1. Initially, both "Commit Order" and "Binlog Flush" queues are empty.
2. Replica applier thread 1 enters the group commit pipeline to register in the
"Commit Order" queue since `log-replica-updates` is disabled on the replica
node.
3. Since both "Commit Order" and "Binlog Flush" queues are empty, the applier
thread 1
3.1. Becomes leader (In Commit_stage_manager::enroll_for()).
3.2. Registers in the commit order queue.
3.3. Acquires the lock MYSQL_BIN_LOG::LOCK_log.
3.4. Commit Order queue is emptied, but the lock MYSQL_BIN_LOG::LOCK_log is
not yet released.
NOTE: SE commit for applier thread is already done by the time it reaches
here.
4. Replica applier thread 2 enters the group commit pipeline to register in the
"Commit Order" queue since `log-replica-updates` is disabled on the replica
node.
5. Since the "Commit Order" queue is empty (emptied by applier thread 1 in 3.4), the
applier thread 2
5.1. Becomes leader (In Commit_stage_manager::enroll_for())
5.2. Registers in the commit order queue.
5.3. Tries to acquire the lock MYSQL_BIN_LOG::LOCK_log. Since it is held by applier
thread 1 it will wait until the lock is released.
6. Client thread enters the group commit pipeline to register in the
"Binlog Flush" queue.
7. Since "Commit Order" queue is not empty (there is applier thread 2 in the
queue), it enters the conditional wait `m_stage_cond_leader` with an
intention to become the leader for both the "Binlog Flush" and
"Commit Order" queues.
8. Applier thread 1 releases the lock MYSQL_BIN_LOG::LOCK_log and proceeds to update
the GTID by calling gtid_state->update_commit_group() from
Commit_order_manager::flush_engine_and_signal_threads().
9. Applier thread 2 acquires the lock MYSQL_BIN_LOG::LOCK_log.
9.1. It checks if there is any thread waiting in the "Binlog Flush" queue
to become the leader. Here it finds the client thread waiting to be
the leader.
9.2. It releases the lock MYSQL_BIN_LOG::LOCK_log and signals on the
cond_var `m_stage_cond_leader` and enters a conditional wait until the
thread's `tx_commit_pending` is set to false by the client thread
(will be done in the
Commit_stage_manager::process_final_stage_for_ordered_commit_group()
called by client thread from fetch_and_process_flush_stage_queue()).
10. The client thread wakes up from the cond_var `m_stage_cond_leader`. The
thread has now become a leader and it is its responsibility to update GTID
of applier thread 2.
10.1. It acquires the lock MYSQL_BIN_LOG::LOCK_log.
10.2. Returns from `enroll_for()` and proceeds to process the
"Commit Order" and "Binlog Flush" queues.
10.3. Fetches the "Commit Order" and "Binlog Flush" queues.
10.4. Performs the storage engine flush by calling ha_flush_logs() from
fetch_and_process_flush_stage_queue().
10.5. Proceeds to update the GTID of threads in "Commit Order" queue by
calling gtid_state->update_commit_group() from
Commit_stage_manager::process_final_stage_for_ordered_commit_group().
11. At this point, we will have
- Client thread performing GTID update on behalf if applier thread 2 (from step 10.5), and
- Applier thread 1 performing GTID update for itself (from step 8).
Due to the lack of proper synchronization between the above two threads,
there exists a time window where both threads can call
gtid_state->update_commit_group() concurrently.
In subsequent steps, both threads simultaneously try to modify the contents
of the array `commit_group_sidnos` which is used to track the lock status of
sidnos. This concurrent access to `update_commit_group()` can cause a
lock-leak resulting in one thread acquiring the sidno lock and not
releasing at all.
-----------------------------------------------------------------------------------------------------------
Client thread Applier Thread 1
-----------------------------------------------------------------------------------------------------------
update_commit_group() => global_sid_lock->rdlock(); update_commit_group() => global_sid_lock->rdlock();
calls update_gtids_impl_lock_sidnos() calls update_gtids_impl_lock_sidnos()
set commit_group_sidno[2] = true set commit_group_sidno[2] = true
lock_sidno(2) -> successful
lock_sidno(2) -> waits
update_gtids_impl_own_gtid() -> Add the thd->owned_gtid in `executed_gtids()`
if (commit_group_sidnos[2]) {
unlock_sidno(2);
commit_group_sidnos[2] = false;
}
Applier thread continues..
lock_sidno(2) -> successful
update_gtids_impl_own_gtid() -> Add the thd->owned_gtid in `executed_gtids()`
if (commit_group_sidnos[2]) { <=== this check fails and lock is not released.
unlock_sidno(2);
commit_group_sidnos[2] = false;
}
Client thread continues without releasing the lock
-----------------------------------------------------------------------------------------------------------
12. As the above lock-leak can also happen the other way i.e, the applier
thread fails to unlock, there can be different consequences hereafter.
13. If the client thread continues without releasing the lock, then at a later
stage, it can enter into a deadlock with the applier thread performing a
GTID update with stack trace.
Client_thread
-------------
#1 __GI___lll_lock_wait
#2 ___pthread_mutex_lock
#3 native_mutex_lock <= waits for commit lock while holding sidno lock
#4 Commit_stage_manager::enroll_for
#5 MYSQL_BIN_LOG::change_stage
percona#6 MYSQL_BIN_LOG::ordered_commit
percona#7 MYSQL_BIN_LOG::commit
percona#8 ha_commit_trans
percona#9 trans_commit_implicit
percona#10 mysql_create_like_table
percona#11 Sql_cmd_create_table::execute
percona#12 mysql_execute_command
percona#13 dispatch_sql_command
Applier thread
--------------
#1 ___pthread_mutex_lock
#2 native_mutex_lock
#3 safe_mutex_lock
#4 Gtid_state::update_gtids_impl_lock_sidnos <= waits for sidno lock
#5 Gtid_state::update_commit_group
percona#6 Commit_order_manager::flush_engine_and_signal_threads <= acquires commit lock here
percona#7 Commit_order_manager::finish
percona#8 Commit_order_manager::wait_and_finish
percona#9 ha_commit_low
percona#10 trx_coordinator::commit_in_engines
percona#11 MYSQL_BIN_LOG::commit
percona#12 ha_commit_trans
percona#13 trans_commit
percona#14 Xid_log_event::do_commit
percona#15 Xid_apply_log_event::do_apply_event_worker
percona#16 Slave_worker::slave_worker_exec_event
percona#17 slave_worker_exec_job_group
percona#18 handle_slave_worker
14. If the applier thread continues without releasing the lock, then at a later
stage, it can perform recursive locking while setting the GTID for the next
transaction (in set_gtid_next()).
In debug builds the above case hits the assertion
`safe_mutex_assert_not_owner()` meaning the lock is already acquired by the
replica applier thread when it tries to re-acquire the lock.
Solution
--------
In the above problematic example, when seen from each thread
individually, we can conclude that there is no problem in the order of lock
acquisition, thus there is no need to change the lock order.
However, the root cause for this problem is that multiple threads can
concurrently access to the array `Gtid_state::commit_group_sidnos`.
In its initial implementation, it was expected that threads should
hold the `MYSQL_BIN_LOG::LOCK_commit` before modifying its contents. But it
was not considered when upstream implemented WL#7846 (MTS:
slave-preserve-commit-order when log-slave-updates/binlog is disabled).
With this patch, we now ensure that `MYSQL_BIN_LOG::LOCK_commit` is acquired
when the client thread (binlog flush leader) when it tries to perform GTID
update on behalf of threads waiting in "Commit Order" queue, thus providing a
guarantee that `Gtid_state::commit_group_sidnos` array is never accessed
without the protection of `MYSQL_BIN_LOG::LOCK_commit`.
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… and .6node3rpl Issue #1 Problem: Test fail in 4node4rpl (1 node group). Solution: Skip test when there is only one NG. Issue #2 Problem: Test fail in 6node3rpl (2 node group) with timeout. Test idea is to restart, with nostart option, *ALL* nodes in same node group to check if QMGR handles it wrongly as "node group is missing". In the test only two nodes in same node group are restarted, it works for 2 replica setups but, for 4 replica, test hangs waiting cluster to enter a noStart state. Solution: Instead of restart exactly 2 nodes, restart ALL nodes in a given node group. Change-Id: Iafb0511992a553723013e73593ea10540cd03661
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…EXCEPT SELECT 4) A work-around is to set the optimizer flag to not use hash map de-duplication for INTERSECT, EXCEPT, like so: SET optimizer_switch="hash_set_operations=off"; With hash_set_operations enabled, however, we get too may result rows. For the IN predicate, the set operation is computed repeatedly, with filters pushed down to set set operation operands: -> Filter: <in_optimizer>(c.pk,<exists>(select #2)) (cost=2.25 rows=20) -> Covering index scan on c using idx_c_col_datetime_key (cost=2.25 rows=20) -> Select #2 (subquery in condition; dependent) -> Limit: 1 row(s) (cost=2.61..2.61 rows=1) -> Table scan on <except temporary> (cost=2.61..2.61 rows=1) -> Except materialize with deduplication (cost=0.1..0.1 rows=1) -> Filter: (<cache>(c.pk) = <ref_null_helper>(2)) (cost=0..0 rows=1) -> Rows fetched before execution (cost=0..0 rows=1) -> Filter: (<cache>(c.pk) = <ref_null_helper>(4)) (cost=0..0 rows=1) -> Rows fetched before execution (cost=0..0 rows=1) Only the row with pk==2 should pass the filters under the except node, and that's what happens. However, on repeated execution, the hash map used to implement the Except materialize is not re-initialized to being empty. The patch adds reinitialization of the hash map for such cases. Change-Id: Idf2e36f9085e36748900017a0aad420e4e476f78
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…rong result
This error happens both with hash_set_operations on or off. If we look
at the explain, we can see why it happens:
-> Filter: <in_optimizer>(c.pk,<exists>(select #2))
-> Covering index scan on c using idx_c_col_datetime_key
-> Select #2 (subquery in condition; dependent)
-> Limit: 1 row(s) <--------------------- OK optimization
-> Table scan on <except temporary>
-> Except all materialize
-> Limit: 1 row(s) <--------------------------- problem
-> Table scan on <union temporary>
-> Union all materialize
-> Filter: (<cache>(c.pk) = <ref_null_helper>(2))
-> Rows fetched before execution
-> Filter: (<cache>(c.pk) = <ref_null_helper>(2))
-> Rows fetched before execution
-> Filter: (<cache>(c.pk) = <ref_null_helper>(2))
-> Rows fetched before execution
There is a limit node on top of the left EXCEPT operand right over the
UNION ALL node which shouldn't be there. It used to be a clever
optimization when MySQL only had UNION set operations, but it clearly
is wrong for EXCEPT ALL. For EXCEPT DISTINCT, UNION and INTERSECT, it
is fine, though.
The solution is to skip pushed down limits in the presence of EXCEPT
ALL inside subqueries, unless it is the top query block in the
subquery's query_expression, i.e. we retain the top-most limit 1 above.
Change-Id: Idf784cbfbe8efbaca03ad17c8c42d73ab7acaa1a
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… for connection xxx'.
The new iterator based explains are not impacted.
The issue here is a race condition. More than one thread is using the
query term iterator at the same time (whoch is neithe threas safe nor
reantrant), and part of its state is in the query terms being visited
which leads to interference/race conditions.
a) the explain thread
uses an iterator here:
Sql_cmd_explain_other_thread::execute
is inspecting the Query_expression of the running query
calling master_query_expression()->find_blocks_query_term which uses
an iterator over the query terms in the query expression:
for (auto qt : query_terms<>()) {
if (qt->query_block() == qb) {
return qt;
}
}
the above search fails to find qb due to the interference of the
thread b), see below, and then tries to access a nullpointer:
* thread percona#36, name = ‘connection’, stop reason = EXC_BAD_ACCESS (code=1, address=0x0)
frame #0: 0x000000010bb3cf0d mysqld`Query_block::type(this=0x00007f8f82719088) const at sql_lex.cc:4441:11
frame #1: 0x000000010b83763e mysqld`(anonymous namespace)::Explain::explain_select_type(this=0x00007000020611b8) at opt_explain.cc:792:50
frame #2: 0x000000010b83cc4d mysqld`(anonymous namespace)::Explain_join::explain_select_type(this=0x00007000020611b8) at opt_explain.cc:1487:21
frame #3: 0x000000010b837c34 mysqld`(anonymous namespace)::Explain::prepare_columns(this=0x00007000020611b8) at opt_explain.cc:744:26
frame #4: 0x000000010b83ea0e mysqld`(anonymous namespace)::Explain_join::explain_qep_tab(this=0x00007000020611b8, tabnum=0) at opt_explain.cc:1415:32
frame #5: 0x000000010b83ca0a mysqld`(anonymous namespace)::Explain_join::shallow_explain(this=0x00007000020611b8) at opt_explain.cc:1364:9
frame percona#6: 0x000000010b83379b mysqld`(anonymous namespace)::Explain::send(this=0x00007000020611b8) at opt_explain.cc:770:14
frame percona#7: 0x000000010b834147 mysqld`explain_query_specification(explain_thd=0x00007f8fbb111e00, query_thd=0x00007f8fbb919c00, query_term=0x00007f8f82719088, ctx=CTX_JOIN) at opt_explain.cc:2088:20
frame percona#8: 0x000000010bd36b91 mysqld`Query_expression::explain_query_term(this=0x00007f8f7a090360, explain_thd=0x00007f8fbb111e00, query_thd=0x00007f8fbb919c00, qt=0x00007f8f82719088) at sql_union.cc:1519:11
frame percona#9: 0x000000010bd36c68 mysqld`Query_expression::explain_query_term(this=0x00007f8f7a090360, explain_thd=0x00007f8fbb111e00, query_thd=0x00007f8fbb919c00, qt=0x00007f8f8271d748) at sql_union.cc:1526:13
frame percona#10: 0x000000010bd373f7 mysqld`Query_expression::explain(this=0x00007f8f7a090360, explain_thd=0x00007f8fbb111e00, query_thd=0x00007f8fbb919c00) at sql_union.cc:1591:7
frame percona#11: 0x000000010b835820 mysqld`mysql_explain_query_expression(explain_thd=0x00007f8fbb111e00, query_thd=0x00007f8fbb919c00, unit=0x00007f8f7a090360) at opt_explain.cc:2392:17
frame percona#12: 0x000000010b835400 mysqld`explain_query(explain_thd=0x00007f8fbb111e00, query_thd=0x00007f8fbb919c00, unit=0x00007f8f7a090360) at opt_explain.cc:2353:13
* frame percona#13: 0x000000010b8363e4 mysqld`Sql_cmd_explain_other_thread::execute(this=0x00007f8fba585b68, thd=0x00007f8fbb111e00) at opt_explain.cc:2531:11
frame percona#14: 0x000000010bba7d8b mysqld`mysql_execute_command(thd=0x00007f8fbb111e00, first_level=true) at sql_parse.cc:4648:29
frame percona#15: 0x000000010bb9e230 mysqld`dispatch_sql_command(thd=0x00007f8fbb111e00, parser_state=0x0000700002065de8) at sql_parse.cc:5303:19
frame percona#16: 0x000000010bb9a4cb mysqld`dispatch_command(thd=0x00007f8fbb111e00, com_data=0x0000700002066e38, command=COM_QUERY) at sql_parse.cc:2135:7
frame percona#17: 0x000000010bb9c846 mysqld`do_command(thd=0x00007f8fbb111e00) at sql_parse.cc:1464:18
frame percona#18: 0x000000010b2f2574 mysqld`handle_connection(arg=0x0000600000e34200) at connection_handler_per_thread.cc:304:13
frame percona#19: 0x000000010e072fc4 mysqld`pfs_spawn_thread(arg=0x00007f8fba8160b0) at pfs.cc:3051:3
frame percona#20: 0x00007ff806c2b202 libsystem_pthread.dylib`_pthread_start + 99
frame percona#21: 0x00007ff806c26bab libsystem_pthread.dylib`thread_start + 15
b) the query thread being explained is itself performing LEX::cleanup
and as part of the iterates over the query terms, but still allows
EXPLAIN of the query plan since
thd->query_plan.set_query_plan(SQLCOM_END, ...)
hasn't been called yet.
20:frame: Query_terms<(Visit_order)1, (Visit_leaves)0>::Query_term_iterator::operator++() (in mysqld) (query_term.h:613)
21:frame: Query_expression::cleanup(bool) (in mysqld) (sql_union.cc:1861)
22:frame: LEX::cleanup(bool) (in mysqld) (sql_lex.h:4286)
30:frame: Sql_cmd_dml::execute(THD*) (in mysqld) (sql_select.cc:799)
31:frame: mysql_execute_command(THD*, bool) (in mysqld) (sql_parse.cc:4648)
32:frame: dispatch_sql_command(THD*, Parser_state*) (in mysqld) (sql_parse.cc:5303)
33:frame: dispatch_command(THD*, COM_DATA const*, enum_server_command) (in mysqld) (sql_parse.cc:2135)
34:frame: do_command(THD*) (in mysqld) (sql_parse.cc:1464)
57:frame: handle_connection(void*) (in mysqld) (connection_handler_per_thread.cc:304)
58:frame: pfs_spawn_thread(void*) (in mysqld) (pfs.cc:3053)
65:frame: _pthread_start (in libsystem_pthread.dylib) + 99
66:frame: thread_start (in libsystem_pthread.dylib) + 15
Solution:
This patch solves the issue by removing iterator state from
Query_term, making the query_term iterators thread safe. This solution
labels every child query_term with its index in its parent's
m_children vector. The iterator can therefore easily compute the next
child to visit based on Query_term::m_sibling_idx.
A unit test case is added to check reentrancy.
One can also manually verify that we have no remaining race condition
by running two client connections files (with \. <file>) with a big
number of copies of the repro query in one connection and a big number
of EXPLAIN format=json FOR <connection>, e.g.
EXPLAIN FORMAT=json FOR CONNECTION 8\G
in the other. The actual connection number would need to verified
in connection one, of course.
Change-Id: Ie7d56610914738ccbbecf399ccc4f465f7d26ea7
lukin-oleksiy
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Dec 2, 2024
This is a combination of 5 commits.
This is the 1st commit message:
WL#15746: TLS Enhancements for HeatWave-AutoML & Dask Comm. Upgrade
Problem:
--------
- HeatWave-AutoML communication was unauthenticated, unauthorized,
and unencrypted.
- Dask communication utilized TCP, not aligning with FedRamp
guidelines.
Solution:
---------
- Introduced TLS and mTLS in HeatWave-AutoML's plugin and driver for
authentication, authorization, and encryption.
- Applied TLS to Dask to ensure authentication, encryption, and
authorization.
Dask Authorization (OCID-based):
--------------------------------
1. For each DBsystem:
- MySQL node sends OCIDs of authorized nodes to the head driver
via:
a. rapid_net_nodes
b. rapid_net_allowed_ocids (older API, mainly for MTR tests)
- Scenarios:
a. All OCIDs provided: Dask authorizes.
b. Any OCID absent: ML call fails with message.
2. During Dask worker registration to the Dask scheduler, a script is
dispatched to the Dask worker for execution, retrieving the worker's
OCID for authorization purposes.
- If the OCID isn't approved, the connection is denied, terminating
the worker and causing the ML query to fail.
3. For every Dask worker (both as listener and connector), an OCID-
based authorization is performed post SSL/TLS connection handshake.
The process compares the OCID from the peer's certificate against
the allowed_ocids received from the HeatWave-AutoML MySQL plugin.
HWAML Plugin Changes:
---------------------
- Sourced certificate data and SSL setup from disk, incorporating
SSL/TLS for HWAML.
- Reused "keystore" variable to specify disk location for
certificate retrieval.
- Certificates and keys expected in PKCS12 format.
- Introduced "have_ml_encryption" variable (default=0).
> Acts as a switch to explicitly deactivate HWAML network
encryption, akin to "disable_net_encryption" affecting
network encryption for HeatWave. Set to 1 to enable.
- Introduced a customized verifier function for verify_callback to
be set in SSL_CTX_set_verify and used in the handshake process
of SSL/TLS. The customized verifier function will perform
instance id (OCID) based authorization on the plugin side during
standard SSL/TLS handshake process.
- CRL (Certificate Revocation List) checks are also conducted if CRL
Distribution Points are present and accessible in the provided
certificate.
HWAML Driver Changes & OCID-based Authorization:
------------------------------------------------
- Introduced "enable_encryption" (default=0).
> Set to 1 to enable encryption.
- When receiving a new connection request and encryption is on, the
driver performs OCID-based self-checking, comparing OCID retrieved
from its own instance principal with the OCID in the
provided certificate on disk.
- The driver compares OCID from "mysql_compute_id" and extracted OCID
from mTLS certificate during connection.
- Introduced "cert_dir" argument for certificate directory
specification.
- Expected files: cert_chain.pem, certificate.pem, private_key.pem.
> OCID should be in the userID (UID) or CN field of the
certificate.pem subject.
- CRL (Certificate Revocation List) checks are also conducted post
handshake, if CRL Distribution Points are present and accessible in
the provided certificate, alongside OCID authorization.
Encryption Behavior:
--------------------
- If encryption is deactivated on both plugin and driver side, HWAML
will work without encryption as it was before this commit.
Enabling Encryption:
--------------------
- By default, "have_ml_encryption" and "enable_encryption" are set to 0
> Encryption is disabled by default.
- For the HWAML plugin:
> "have_ml_encryption" set to 1 (default is 0).
> Specify the .pfx file's path using the "keystore".
- For the HWAML Driver:
> "enable_encryption" set to 1 (default is 0)
> Specify "mysql_instance_id" and "cert_dir".
Testing:
--------
- MTR has been modified for the encryption setup.
> Runs with encryption if "OCI_INSTANCE_ID" is set to a valid
value.
- On OCI (when "OLRAPID_KEYSTORE" is not set):
> Certificates and keys are generated; PEMs for driver and PKCS12
for plugin.
- On AWS (when "OLRAPID_KEYSTORE" is set as the path to PKCS12
keystore files):
> PEM files are extracted from the provided PKCS12 and used for
the driver. The plugin uses the provided PKCS12 keystore file.
Change-Id: I553ca135241e03484db6debbe186e6d34d582bf4
This is the commit message #2:
WL#15746 - Adding ML encryption support to BM
Enabling ML encryption on Baumeister:
- Certificates are generated on MySQLd during initialization
- Needed certicates for workers are packaged and sent to worker nodes
- Workers use packaged files to generate their certificates
- Arguments are added to driver.py invoke
- Keystore path is added to mysql config
Change-Id: I11a5cc5926488ff4fbf91bb6c10a091358db7dc9
This is the commit message #3:
WL#15746: Enhanced CRL Daemon Checker
Issue
=====
The previous design assumed a plain HTTPS link for the CRL distribution
point, accessible to all. This assumption no longer holds, as public
accessibility for CRL distribution contradicts OCI guidelines. Now, the
CRL distribution point in certificates provided by the control plane is
expected to be protected by OCI Instance Principal Authentication.
However, using this authentication method introduces a delay of several
seconds, which is impractical for HeatWave-AutoML.
Solution
========
The CRL fetching code now uses OCI Instance Principal Authentication.
To mitigate performance issues, the CRL checking process has been
redesigned. Instead of enforcing CRL checks per connection in MySQL
Plugin and HeatWave-AutoML Driver communications, a daemon thread in
HeatWave-AutoML Driver, Dask scheduler, and Dask Worker now periodically
fetches and verifies the CRL against all active connections. This
separation minimizes performance impacts. Consequently, MySQL Plugin's
CRL checks have been removed, as checks in the Driver, Scheduler, and
Worker sufficiently cover all cluster nodes.
Changes
=======
- Implemented CRL checker as a daemon thread in Driver, Scheduler, and
Worker.
- Each connection/socket has an associated CRL checker.
- CRL checks occur periodically at set intervals.
- Skips CRL check if the CRL is temporarily unavailable.
- Failing a CRL check results in the associated connection/socket being
closed. On the Driver, a stop event is triggered (akin to CTRL-C).
Change-Id: Id998cfe9e15d9236291b0ae420d65c2197837966
This is the commit message #4:
WL#15746: Fix Dask workers being shutdown without releasing address
Issue
=====
Dask workers getting shutting but not releasing the address used
properly sometimes.
Solution
========
Reverted some changes in heatwave_cluster.py in dask worker shutdown
function. Hopefully this will fix the address issue
Change-Id: I5a6749b5a25b0ccb73ba7369e545bc010da1b84f
This is the commit message #5:
WL#15746: Implement Dask Worker Join Timeout for Head Node
Issue:
======
In the cluster_shutdown method, the join operation on the head node's
worker process lacked a timeout. This led to potential indefinite
waiting and eventual hanging of the head node.
Solution:
=========
A timeout has been introduced for the worker process join on the head
node. Unlike non-head nodes, which rely on worker join to complete Dask
tasks and cannot have a timeout, the head node can safely implement
this. Now, if the worker process on the head node fails to shut down
post-join, indicating a timeout, it will be manually terminated. This
ensures proper release of associated resources and prevents hanging of
the head node.
Additional Change:
==================
Added Cert Rotation Guard for DASK clusters. This feature initiates on
the first plugin-driver connection when the DASK cluster is off,
recording the certificate's expiry date. During driver idle times,
it checks the current cert's expiry against this date. If it detects a
change, indicating a certificate rotation, it shuts down the DASK
cluster. The cluster restarts on the next connection request, ensuring
the use of the latest certificate.
Change-Id: Ie63a2e2b7664e05e1622d8bd6503663e13fa73cb
lukin-oleksiy
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…N (SELECT 2 EXCEPT SELECT 4) A work-around is to set the optimizer flag to not use hash map de-duplication for INTERSECT, EXCEPT, like so: SET optimizer_switch="hash_set_operations=off"; With hash_set_operations enabled, however, we get too may result rows. For the IN predicate, the set operation is computed repeatedly, with filters pushed down to set set operation operands: -> Filter: <in_optimizer>(c.pk,<exists>(select #2)) (cost=2.25 rows=20) -> Covering index scan on c using idx_c_col_datetime_key (cost=2.25 rows=20) -> Select #2 (subquery in condition; dependent) -> Limit: 1 row(s) (cost=2.61..2.61 rows=1) -> Table scan on <except temporary> (cost=2.61..2.61 rows=1) -> Except materialize with deduplication (cost=0.1..0.1 rows=1) -> Filter: (<cache>(c.pk) = <ref_null_helper>(2)) (cost=0..0 rows=1) -> Rows fetched before execution (cost=0..0 rows=1) -> Filter: (<cache>(c.pk) = <ref_null_helper>(4)) (cost=0..0 rows=1) -> Rows fetched before execution (cost=0..0 rows=1) Only the row with pk==2 should pass the filters under the except node, and that's what happens. However, on repeated execution, the hash map used to implement the Except materialize is not re-initialized to being empty. The patch adds reinitialization of the hash map for such cases. Change-Id: Idf2e36f9085e36748900017a0aad420e4e476f78
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Upstream commit ID : fb-mysql-5.6.35/8cb1dc836b68f1f13e8b2655b2b8cb2d57f400b3 PS-5217 : Merge fb-prod201803 Summary: Original report: https://jira.mariadb.org/browse/MDEV-15816 To reproduce this bug just following below steps, client 1: USE test; CREATE TABLE t1 (i INT) ENGINE=MyISAM; HANDLER t1 OPEN h; CREATE TABLE t2 (i INT) ENGINE=RocksDB; LOCK TABLES t2 WRITE; client 2: FLUSH TABLES WITH READ LOCK; client 1: INSERT INTO t2 VALUES (1); So client 1 acquired the lock and set m_lock_rows = RDB_LOCK_WRITE. Then client 2 calls store_lock(TL_IGNORE) and m_lock_rows was wrongly set to RDB_LOCK_NONE, as below ``` #0 myrocks::ha_rocksdb::store_lock (this=0x7fffbc03c7c8, thd=0x7fffc0000ba0, to=0x7fffc0011220, lock_type=TL_IGNORE) #1 get_lock_data (thd=0x7fffc0000ba0, table_ptr=0x7fffe84b7d20, count=1, flags=2) #2 mysql_lock_abort_for_thread (thd=0x7fffc0000ba0, table=0x7fffbc03bbc0) #3 THD::notify_shared_lock (this=0x7fffc0000ba0, ctx_in_use=0x7fffbc000bd8, needs_thr_lock_abort=true) #4 MDL_lock::notify_conflicting_locks (this=0x555557a82380, ctx=0x7fffc0000cc8) #5 MDL_context::acquire_lock (this=0x7fffc0000cc8, mdl_request=0x7fffe84b8350, lock_wait_timeout=2) percona#6 Global_read_lock::lock_global_read_lock (this=0x7fffc0003fe0, thd=0x7fffc0000ba0) ``` Finally, client 1 "INSERT INTO..." hits the Assertion 'm_lock_rows == RDB_LOCK_WRITE' failed in myrocks::ha_rocksdb::write_row() Fix this bug by not setting m_locks_rows if lock_type == TL_IGNORE. Closes facebook/mysql-5.6#838 Pull Request resolved: facebook/mysql-5.6#871 Differential Revision: D9417382 Pulled By: lth fbshipit-source-id: c36c164e06c
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Upstream commit ID : fb-mysql-5.6.35/911d1a387a0d80f3ba52b7432c1abdbd7e8cb220 PS-6867 : Merge fb-prod201905 Summary: Missed a few in earlier fixes for AutoInitCopy rule. Also added a few fixes for anoymous class rule and local shadowing rule. Reviewed By: luqun Differential Revision: D15467213 fbshipit-source-id: 9325852dbdd
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Import all functions and changes required to compile MyRocks (-DWITH_ROCKSDB=1). ---------------------------------------------------------------------- PS-9218 merge: Merge MySQL 8.4.0 (GCC 12.3 RelWithDebInfo fixes) (percona#5356) https://perconadev.atlassian.net/browse/PS-9218 Added more warning suppressions for RocksDB submodule files that appeared in GCC 12.3 in RelWithDebInfo mode. ---------------------------------------------------------------------- PS-9218: Merge MySQL 8.4.0 (fix gcc-14 build) #2 (rocksdb part)
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…s=0 and a local DDL
executed
https://perconadev.atlassian.net/browse/PS-9018
Problem
-------
In high concurrency scenarios, MySQL replica can enter into a deadlock due to a
race condition between the replica applier thread and the client thread
performing a binlog group commit.
Analysis
--------
It needs at least 3 threads for this deadlock to happen
1. One client thread
2. Two replica applier threads
How this deadlock happens?
--------------------------
0. Binlog is enabled on replica, but log_replica_updates is disabled.
1. Initially, both "Commit Order" and "Binlog Flush" queues are empty.
2. Replica applier thread 1 enters the group commit pipeline to register in the
"Commit Order" queue since `log-replica-updates` is disabled on the replica
node.
3. Since both "Commit Order" and "Binlog Flush" queues are empty, the applier
thread 1
3.1. Becomes leader (In Commit_stage_manager::enroll_for()).
3.2. Registers in the commit order queue.
3.3. Acquires the lock MYSQL_BIN_LOG::LOCK_log.
3.4. Commit Order queue is emptied, but the lock MYSQL_BIN_LOG::LOCK_log is
not yet released.
NOTE: SE commit for applier thread is already done by the time it reaches
here.
4. Replica applier thread 2 enters the group commit pipeline to register in the
"Commit Order" queue since `log-replica-updates` is disabled on the replica
node.
5. Since the "Commit Order" queue is empty (emptied by applier thread 1 in 3.4), the
applier thread 2
5.1. Becomes leader (In Commit_stage_manager::enroll_for())
5.2. Registers in the commit order queue.
5.3. Tries to acquire the lock MYSQL_BIN_LOG::LOCK_log. Since it is held by applier
thread 1 it will wait until the lock is released.
6. Client thread enters the group commit pipeline to register in the
"Binlog Flush" queue.
7. Since "Commit Order" queue is not empty (there is applier thread 2 in the
queue), it enters the conditional wait `m_stage_cond_leader` with an
intention to become the leader for both the "Binlog Flush" and
"Commit Order" queues.
8. Applier thread 1 releases the lock MYSQL_BIN_LOG::LOCK_log and proceeds to update
the GTID by calling gtid_state->update_commit_group() from
Commit_order_manager::flush_engine_and_signal_threads().
9. Applier thread 2 acquires the lock MYSQL_BIN_LOG::LOCK_log.
9.1. It checks if there is any thread waiting in the "Binlog Flush" queue
to become the leader. Here it finds the client thread waiting to be
the leader.
9.2. It releases the lock MYSQL_BIN_LOG::LOCK_log and signals on the
cond_var `m_stage_cond_leader` and enters a conditional wait until the
thread's `tx_commit_pending` is set to false by the client thread
(will be done in the
Commit_stage_manager::process_final_stage_for_ordered_commit_group()
called by client thread from fetch_and_process_flush_stage_queue()).
10. The client thread wakes up from the cond_var `m_stage_cond_leader`. The
thread has now become a leader and it is its responsibility to update GTID
of applier thread 2.
10.1. It acquires the lock MYSQL_BIN_LOG::LOCK_log.
10.2. Returns from `enroll_for()` and proceeds to process the
"Commit Order" and "Binlog Flush" queues.
10.3. Fetches the "Commit Order" and "Binlog Flush" queues.
10.4. Performs the storage engine flush by calling ha_flush_logs() from
fetch_and_process_flush_stage_queue().
10.5. Proceeds to update the GTID of threads in "Commit Order" queue by
calling gtid_state->update_commit_group() from
Commit_stage_manager::process_final_stage_for_ordered_commit_group().
11. At this point, we will have
- Client thread performing GTID update on behalf if applier thread 2 (from step 10.5), and
- Applier thread 1 performing GTID update for itself (from step 8).
Due to the lack of proper synchronization between the above two threads,
there exists a time window where both threads can call
gtid_state->update_commit_group() concurrently.
In subsequent steps, both threads simultaneously try to modify the contents
of the array `commit_group_sidnos` which is used to track the lock status of
sidnos. This concurrent access to `update_commit_group()` can cause a
lock-leak resulting in one thread acquiring the sidno lock and not
releasing at all.
-----------------------------------------------------------------------------------------------------------
Client thread Applier Thread 1
-----------------------------------------------------------------------------------------------------------
update_commit_group() => global_sid_lock->rdlock(); update_commit_group() => global_sid_lock->rdlock();
calls update_gtids_impl_lock_sidnos() calls update_gtids_impl_lock_sidnos()
set commit_group_sidno[2] = true set commit_group_sidno[2] = true
lock_sidno(2) -> successful
lock_sidno(2) -> waits
update_gtids_impl_own_gtid() -> Add the thd->owned_gtid in `executed_gtids()`
if (commit_group_sidnos[2]) {
unlock_sidno(2);
commit_group_sidnos[2] = false;
}
Applier thread continues..
lock_sidno(2) -> successful
update_gtids_impl_own_gtid() -> Add the thd->owned_gtid in `executed_gtids()`
if (commit_group_sidnos[2]) { <=== this check fails and lock is not released.
unlock_sidno(2);
commit_group_sidnos[2] = false;
}
Client thread continues without releasing the lock
-----------------------------------------------------------------------------------------------------------
12. As the above lock-leak can also happen the other way i.e, the applier
thread fails to unlock, there can be different consequences hereafter.
13. If the client thread continues without releasing the lock, then at a later
stage, it can enter into a deadlock with the applier thread performing a
GTID update with stack trace.
Client_thread
-------------
#1 __GI___lll_lock_wait
#2 ___pthread_mutex_lock
#3 native_mutex_lock <= waits for commit lock while holding sidno lock
#4 Commit_stage_manager::enroll_for
#5 MYSQL_BIN_LOG::change_stage
percona#6 MYSQL_BIN_LOG::ordered_commit
percona#7 MYSQL_BIN_LOG::commit
percona#8 ha_commit_trans
percona#9 trans_commit_implicit
percona#10 mysql_create_like_table
percona#11 Sql_cmd_create_table::execute
percona#12 mysql_execute_command
percona#13 dispatch_sql_command
Applier thread
--------------
#1 ___pthread_mutex_lock
#2 native_mutex_lock
#3 safe_mutex_lock
#4 Gtid_state::update_gtids_impl_lock_sidnos <= waits for sidno lock
#5 Gtid_state::update_commit_group
percona#6 Commit_order_manager::flush_engine_and_signal_threads <= acquires commit lock here
percona#7 Commit_order_manager::finish
percona#8 Commit_order_manager::wait_and_finish
percona#9 ha_commit_low
percona#10 trx_coordinator::commit_in_engines
percona#11 MYSQL_BIN_LOG::commit
percona#12 ha_commit_trans
percona#13 trans_commit
percona#14 Xid_log_event::do_commit
percona#15 Xid_apply_log_event::do_apply_event_worker
percona#16 Slave_worker::slave_worker_exec_event
percona#17 slave_worker_exec_job_group
percona#18 handle_slave_worker
14. If the applier thread continues without releasing the lock, then at a later
stage, it can perform recursive locking while setting the GTID for the next
transaction (in set_gtid_next()).
In debug builds the above case hits the assertion
`safe_mutex_assert_not_owner()` meaning the lock is already acquired by the
replica applier thread when it tries to re-acquire the lock.
Solution
--------
In the above problematic example, when seen from each thread
individually, we can conclude that there is no problem in the order of lock
acquisition, thus there is no need to change the lock order.
However, the root cause for this problem is that multiple threads can
concurrently access to the array `Gtid_state::commit_group_sidnos`.
In its initial implementation, it was expected that threads should
hold the `MYSQL_BIN_LOG::LOCK_commit` before modifying its contents. But it
was not considered when upstream implemented WL#7846 (MTS:
slave-preserve-commit-order when log-slave-updates/binlog is disabled).
With this patch, we now ensure that `MYSQL_BIN_LOG::LOCK_commit` is acquired
when the client thread (binlog flush leader) when it tries to perform GTID
update on behalf of threads waiting in "Commit Order" queue, thus providing a
guarantee that `Gtid_state::commit_group_sidnos` array is never accessed
without the protection of `MYSQL_BIN_LOG::LOCK_commit`.
lukin-oleksiy
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that referenced
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Jan 23, 2025
PS-5741: Incorrect use of memset_s in keyring_vault.
Fixed the usage of memset_s. The arguments should be:
void memset_s(void *dest, size_t dest_max, int c, size_t n)
where the 2nd argument is size of buffer and the 3rd is
argument is character to fill.
---------------------------------------------------------------------------
PS-7769 - Fix use-after-return error in audit_log_exclude_accounts_validate
---
*Problem:*
`st_mysql_value::val_str` might return a pointer to `buf` which after
the function called is deleted. Therefore the value in `save`, after
reuturnin from the function, is invalid.
In this particular case, the error is not manifesting as val_str`
returns memory allocated with `thd_strmake` and it does not use `buf`.
*Solution:*
Allocate memory with `thd_strmake` so the memory in `save` is not local.
---------------------------------------------------------------------------
Fix test main.bug12969156 when WITH_ASAN=ON
*Problem:*
ASAN complains about stack-buffer-overflow on function `mysql_heartbeat`:
```
==90890==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7fe746d06d14 at pc 0x7fe760f5b017 bp 0x7fe746d06cd0 sp 0x7fe746d06478
WRITE of size 24 at 0x7fe746d06d14 thread T16777215
Address 0x7fe746d06d14 is located in stack of thread T26 at offset 340 in frame
#0 0x7fe746d0a55c in mysql_heartbeat(void*) /home/yura/ws/percona-server/plugin/daemon_example/daemon_example.cc:62
This frame has 4 object(s):
[48, 56) 'result' (line 66)
[80, 112) '_db_stack_frame_' (line 63)
[144, 200) 'tm_tmp' (line 67)
[240, 340) 'buffer' (line 65) <== Memory access at offset 340 overflows this variable
HINT: this may be a false positive if your program uses some custom stack unwind mechanism, swapcontext or vfork
(longjmp and C++ exceptions *are* supported)
Thread T26 created by T25 here:
#0 0x7fe760f5f6d5 in __interceptor_pthread_create ../../../../src/libsanitizer/asan/asan_interceptors.cpp:216
#1 0x557ccbbcb857 in my_thread_create /home/yura/ws/percona-server/mysys/my_thread.c:104
#2 0x7fe746d0b21a in daemon_example_plugin_init /home/yura/ws/percona-server/plugin/daemon_example/daemon_example.cc:148
#3 0x557ccb4c69c7 in plugin_initialize /home/yura/ws/percona-server/sql/sql_plugin.cc:1279
#4 0x557ccb4d19cd in mysql_install_plugin /home/yura/ws/percona-server/sql/sql_plugin.cc:2279
#5 0x557ccb4d218f in Sql_cmd_install_plugin::execute(THD*) /home/yura/ws/percona-server/sql/sql_plugin.cc:4664
percona#6 0x557ccb47695e in mysql_execute_command(THD*, bool) /home/yura/ws/percona-server/sql/sql_parse.cc:5160
percona#7 0x557ccb47977c in mysql_parse(THD*, Parser_state*, bool) /home/yura/ws/percona-server/sql/sql_parse.cc:5952
percona#8 0x557ccb47b6c2 in dispatch_command(THD*, COM_DATA const*, enum_server_command) /home/yura/ws/percona-server/sql/sql_parse.cc:1544
percona#9 0x557ccb47de1d in do_command(THD*) /home/yura/ws/percona-server/sql/sql_parse.cc:1065
percona#10 0x557ccb6ac294 in handle_connection /home/yura/ws/percona-server/sql/conn_handler/connection_handler_per_thread.cc:325
percona#11 0x557ccbbfabb0 in pfs_spawn_thread /home/yura/ws/percona-server/storage/perfschema/pfs.cc:2198
percona#12 0x7fe760ab544f in start_thread nptl/pthread_create.c:473
```
The reason is that `my_thread_cancel` is used to finish the daemon thread. This is not and orderly way of finishing the thread. ASAN does not register the stack variables are not used anymore which generates the error above.
This is a benign error as all the variables are on the stack.
*Solution*:
Finish the thread in orderly way by using a signalling variable.
---------------------------------------------------------------------------
PS-8204: Fix XML escape rules for audit plugin
https://jira.percona.com/browse/PS-8204
There was a wrong length specified for some XML
escape rules. As a result of this terminating null symbol from
replacement rule was copied into resulting string. This lead to
quer text truncation in audit log file.
In addition added empty replacement rules for '\b' and 'f' symbols
which just remove them from resulting string. These symboles are
not supported in XML 1.0.
---------------------------------------------------------------------------
PS-8854: Add main.percona_udf MTR test
Add a test to check FNV1A_64, FNV_64, and MURMUR_HASH user-defined functions.
---------------------------------------------------------------------------
PS-9218: Merge MySQL 8.4.0 (fix gcc-14 build)
https://perconadev.atlassian.net/browse/PS-9218
lukin-oleksiy
pushed a commit
that referenced
this pull request
Jan 23, 2025
…n read() syscall over network https://jira.percona.com/browse/PS-8592 Description ----------- GR suffered from problems caused by the security probes and network scanner processes connecting to the group replication communication port. This usually is not a problem, but poses a serious threat when another member tries to join the cluster by initialting a connection to the member which is affected by external processes using the port dedicated for group communication for longer durations. On such activites by external processes, the SSL enabled server stalled forever on the SSL_accept() call waiting for handshake data. Below is the stacktrace: Thread 55 (Thread 0x7f7bb77ff700 (LWP 2198598)): #0 in read () #1 in sock_read () #2 in BIO_read () #3 in ssl23_read_bytes () #4 in ssl23_get_client_hello () #5 in ssl23_accept () percona#6 in xcom_tcp_server_startup(Xcom_network_provider*) () When the server stalled in the above path forever, it prohibited other members to join the cluster resulting in the following messages on the joiner server's logs. [ERROR] [MY-011640] [Repl] Plugin group_replication reported: 'Timeout on wait for view after joining group' [ERROR] [MY-011735] [Repl] Plugin group_replication reported: '[GCS] The member is already leaving or joining a group.' Solution -------- This patch adds two new variables 1. group_replication_xcom_ssl_socket_timeout It is a file-descriptor level timeout in seconds for both accept() and SSL_accept() calls when group replication is listening on the xcom port. When set to a valid value, say for example 5 seconds, both accept() and SSL_accept() return after 5 seconds. The default value has been set to 0 (waits infinitely) for backward compatibility. This variable is effective only when GR is configred with SSL. 2. group_replication_xcom_ssl_accept_retries It defines the number of retries to be performed before closing the socket. For each retry the server thread calls SSL_accept() with timeout defined by the group_replication_xcom_ssl_socket_timeout for the SSL handshake process once the connection has been accepted by the first accept() call. The default value has been set to 10. This variable is effective only when GR is configred with SSL. Note: - Both of the above variables are dynamically configurable, but will become effective only on START GROUP_REPLICATION. ------------------------------------------------------------------------- PS-8844: Fix the failing main.mysqldump_gtid_purged https://jira.percona.com/browse/PS-8844 This patch fixes the test failure of main.mysqldump_gtid_purged that failed due to the uninitialized variable $redirect_stderr in the start_proc_in_background.inc. ---------------------------------------------------------------------- PS-9218: Merge MySQL 8.4.0 (fix terminology in replication tests) https://perconadev.atlassian.net/browse/PS-9218 mysql/mysql-server@44a77b5
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