Merge MySQL 5.6.23 #11

laurynas-biveinis · 2015-02-23T15:09:17Z

http://jenkins.percona.com/job/percona-server-5.6-param/821/

G2

…CHARACTER SET Description: When we try to connect mysql-5.6 server with mysql-4.0 client the error log gets filled with below warning message "[Warning] Client failed to provide its character set. 'latin1' will be used as client character set" Analysis: Since the the client protocol is older than 4.1 and the 4.0 client is not providing the character set while trying to connect to the server. so, the warning message is sent to error log file. Fix: Since the warning message is not necessary, we are removing the warning message.

…OPEN_ON_NAME() OR FTS_IS_SYNC_NEEDED()

Description: Using correct length when moving to next field in cmp_ref. The store length already includes the length bytes of blobs, which is already considered earlier for blob types. Approved by Mattias, Jimmy [rb-7088]

Merge from mysql-5.5

…_ARRAY create_distinct_group() may need some extra space, so do a similar counting in setup_ref_array() to have enough space in st_select_lex::ref_pointer_array Also: shrinking an existing ref_pointer_array, as introduced by WL#5953 - Optimize away useless subquery clauses has to be reversed. The '*' wildcards are fixed in the prepare phase, but not in the execute phase.

WINDOWS TO LINUX CAUSES CRASH - Post fix failure in test script. Approved by Marko via IM

…TING PERL "HOSTNAMES" When building RPMs and using the "rpmbuild" automatic scanning for Perl dependencies, it might interpret "use hostnames" in the "mysql_config.pl" script usage comment as a Perl "use" statement. And then makes the resulting RPMs depends on a non-existing module Perl "hostnames". The comment was changed to prevent this.

Fix broken gcc 4.9.1 debug build by removing end of line noise. In 5.6+ this issue was already fixed by: ------------------------------------------------------------ revno: 3091 committer: Davi Arnaut <davi.arnaut@oracle.com> branch nick: mysql-trunk timestamp: Mon 2011-05-16 11:30:54 -0300 message: Fix warnings emitted by Clang.

UPDATE STATEMENT Problem: JOIN_TAB pointer is not checked before de-referencing it. Analysis: The fact that JOIN_TAB objects are not used for single-table UPDATE and DELETE, is ignored when optimizer is trying to generate simple equality condition from multiple equalities in eliminate_item_equal(). As a result server fails accessing the uninitialized pointer.

COMMUNICATION PACKETS; FEDERATED TABLE Description:- Execution of FLUSH TABLES on a federated table which has been idle for wait_timeout (on the remote server) + tcp_keepalive_time, fails with an error, "ERROR 1160 (08S01): Got an error writing communication packets." Analysis:- During FLUSH TABLE execution the federated table is closed which will inturn close the federated connection. While closing the connection, federated server tries to communincate with the remote server. Since the connection was idle for wait_timeout(on the remote server)+ tcp_keepalive_time, the socket gets closed. So this communication fails because of broken pipe and the error is thrown. But federated connections are expected to reconnect silently. And also it cannot reconnect because the "auto_reconnect" variable is set to 0 in "mysql_close()". Fix:- Before closing the federated connection, in "ha_federated_close()", a check is added which will verify wheather the connection is alive or not. If the connection is not alive, then "mysql->net.error" is set to 2 which will indicate that the connetion is broken. Also the setting of "auto_reconnect" variable to 0 is delayed and is done after "COM_QUIT" command. NOTE:- For reproducing this issue, "tcp_keepalive_time" has to be set to a smaller value. This value is set in the "/proc/sys/net/ipv4/tcp_keepalive_time" file in Unix systems. So we need root permission for changing it, which can't be done through mtr test. So submitting the patch without mtr test.

… REPO For 'make dist': only use 'bzr export' if bzr root == ${CMAKE_SOURCE_DIR} Same thing for git.

…G TO GIT Use 'git log -1; git branch' rather than 'bzr version-info'

Conflicts: cmake/info_macros.cmake.in

Use 'git ls-files' to find source files for etags.

Conflicts: support-files/build-tags

PREVIOUS_GTID EVENT Problem: Previous gtid log event in relay log should not be contributed to seconds behind master calculation. Analysis: A log event contains a timestamp in it's header which represents the time at which it got generated on Master. In relaylog, we have events which got transferred from Master and also contains which were generated on Slave, which we call it as " a relay log event" for eg: when relaylog is rotated, Slave generates and writes Previous_gtid_log_event in to the relay log. These events (which got generated on Slave) contains the timestamp of thread's starting time. When we are calculating Second Behind Master(SBM), the events which are generated on Slave should be ignored and should not contribute to SBM calculation. We already have a logic in the server if (!ev->is_relay_log_event()) { last_master_timestamp= } But the previous gtid log events generated on Slave are not marked as "relay log events" hence last_master_timestamp is getting set with thread's start time and SBM will have wrong value. And also in some situations, we generate Rotate log events on slave to maintain the SQL positions in sync with Master these log events are generated with server_id 0. These events also should not contribute to SBM calculation. Fix: Mark previous_gtid_log_event as relay log event. And don't set last_master_timestamp when server_id= 0.

In 5.6, Ignorable log events were introduced. These events have the flag LOG_EVENT_IGNORABLE_F flag (0x80) set in the flags field. When the server (specifically, the replication receiver and applier threads) sees an event with a type code it does not recognize, the server is supposed to check if this flag is set. If the flag is not set, the server generates an error and stops; if the flag is set, the server ignores the event. The purpose is to allow future server versions to introduce new event types that the slave can ignore (such as informational event types). However, this does not work, since the slave applyer thread explicitly checks if the type code is in the range of known event types, and reports an error, before it goes further and checks if the event is ignorable. To fix the problem, the slave applyer thread does not check if this is a known event type any more. And we also remove unnecessary check for PREVIOUS_GTIDS_LOG_EVENT, then we can replicate from 5.7 with WL#7592 and disabled gtid_mode to 5.6 with disabled gtid_mode without introducing a new type code for PREVIOUS_GTIDS_LOG_EVENT in 5.7.

IN ROW0QUIESCE.CC LINE 683 PROBLEM When flushing the table,innodb tries to store all locks on the table.If we have multiple read locks on the table (which we can achieve using aliases),we try to set the quiesec state of the table to QUIESCE_START multiple times which causes the assert. FIX Relax the assert if table is already in QUIESCE_START state. [Approved by Jimmy rb#7167]

CONTAINING SPACES Problem: This problem happens only if the change buffer is enabled. It does not happen if the change buffer is disabled. Analysis showed that the cause was the buffering of the following sequence of operations for a same record - IBUF_OP_DELETE_MARK, IBUF_OP_INSERT, IBUF_OP_DELETE. Because of this sequence, while merging the change buffer entries into the page, the delete operation (also called purge) found the "record to be purged" without a delete mark. Solution: The above sequence of operations must not be bufferred. This sequence is avoided when change buffer is disabled, because of latching of secondary index page. So it must be avoided when change buffer is enabled by using the "page watch" properly. Once the purge thread has kept a watch for a page in the buffer pool, a concurrent insert operation on the same page must take this into account, and not buffer the operation. rb#7293 approved by Marko.

TMP TABLES FAIL Problem: When too many temp tables are open, server fails instead of giving an error. Solution: The return code from prepare_tmp_table is not checked in QEP_tmp_table::put_record. Added a check for the same.

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 percona#4 0x557ccb4d19cd in mysql_install_plugin /home/yura/ws/percona-server/sql/sql_plugin.cc:2279 percona#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.

…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 percona#4 Commit_stage_manager::enroll_for percona#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 percona#4 Gtid_state::update_gtids_impl_lock_sidnos <= waits for sidno lock percona#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`.