Implement --semi-sync-master-wait-point=AFTER_SYNC|AFTER_COMMIT.
When AFTER_SYNC, the semi-sync wait will be done earlier, before the storage
engine commit rather than after. This means that a transaction will not be
visible on the master until at least one slave has received it.
and small collateral changes
mysql-test/lib/My/Test.pm:
somehow with "print" we get truncated writes sometimes
mysql-test/suite/perfschema/r/digest_table_full.result:
md5 hashes of statement digests differ, because yacc token codes are different in mariadb
mysql-test/suite/perfschema/r/dml_handler.result:
host table is not ported over yet
mysql-test/suite/perfschema/r/information_schema.result:
host table is not ported over yet
mysql-test/suite/perfschema/r/nesting.result:
this differs, because we don't rewrite general log queries, and multi-statement
packets are logged as a one entry. this result file is identical to what mysql-5.6.5
produces with the --log-raw option.
mysql-test/suite/perfschema/r/relaylog.result:
MariaDB modifies the binlog index file directly, while MySQL 5.6 has a feature "crash-safe binlog index" and modifies a special "crash-safe" shadow copy of the index file and then moves it over. That's why this test shows "NONE" index file writes in MySQL and "MANY" in MariaDB.
mysql-test/suite/perfschema/r/server_init.result:
MariaDB initializes the "manager" resources from the "manager" thread, and starts this thread only when --flush-time is not 0. MySQL 5.6 initializes "manager" resources unconditionally on server startup.
mysql-test/suite/perfschema/r/stage_mdl_global.result:
this differs, because MariaDB disables query cache when query_cache_size=0. MySQL does not
do that, and this causes useless mutex locks and waits.
mysql-test/suite/perfschema/r/statement_digest.result:
md5 hashes of statement digests differ, because yacc token codes are different in mariadb
mysql-test/suite/perfschema/r/statement_digest_consumers.result:
md5 hashes of statement digests differ, because yacc token codes are different in mariadb
mysql-test/suite/perfschema/r/statement_digest_long_query.result:
md5 hashes of statement digests differ, because yacc token codes are different in mariadb
mysql-test/suite/rpl/r/rpl_mixed_drop_create_temp_table.result:
will be updated to match 5.6 when alfranio.correia@oracle.com-20110512172919-c1b5kmum4h52g0ni and anders.song@greatopensource.com-20110105052107-zoab0bsf5a6xxk2y are merged
mysql-test/suite/rpl/r/rpl_non_direct_mixed_mixing_engines.result:
will be updated to match 5.6 when anders.song@greatopensource.com-20110105052107-zoab0bsf5a6xxk2y is merged
Essentially, the problem is that safemalloc is excruciatingly
slow as it checks all allocated blocks for overrun at each
memory management primitive, yielding a almost exponential
slowdown for the memory management functions (malloc, realloc,
free). The overrun check basically consists of verifying some
bytes of a block for certain magic keys, which catches some
simple forms of overrun. Another minor problem is violation
of aliasing rules and that its own internal list of blocks
is prone to corruption.
Another issue with safemalloc is rather the maintenance cost
as the tool has a significant impact on the server code.
Given the magnitude of memory debuggers available nowadays,
especially those that are provided with the platform malloc
implementation, maintenance of a in-house and largely obsolete
memory debugger becomes a burden that is not worth the effort
due to its slowness and lack of support for detecting more
common forms of heap corruption.
Since there are third-party tools that can provide the same
functionality at a lower or comparable performance cost, the
solution is to simply remove safemalloc. Third-party tools
can provide the same functionality at a lower or comparable
performance cost.
The removal of safemalloc also allows a simplification of the
malloc wrappers, removing quite a bit of kludge: redefinition
of my_malloc, my_free and the removal of the unused second
argument of my_free. Since free() always check whether the
supplied pointer is null, redudant checks are also removed.
Also, this patch adds unit testing for my_malloc and moves
my_realloc implementation into the same file as the other
memory allocation primitives.
client/mysqldump.c:
Pass my_free directly as its signature is compatible with the
callback type -- which wasn't the case for free_table_ent.
Also, update a few cases missed by the initial patch.
client/mysqltest.cc:
Remove trailing comma.
include/my_alloc.h:
Do not use wrapper.
include/mysql.h.pp:
Update ABI file.
plugin/semisync/semisync_master.h:
Initialize variable.
sql/debug_sync.cc:
Use C linkage.
The root cause of the crash is that a TranxNode is freed before it is used.
A TranxNode is allocated and inserted into the active list each time
a log event is written and flushed into the binlog file.
The memory for TranxNode is allocated with thd_alloc and will be freed
at the end of the statement. The after_commit/after_rollback callback
was supposed to be called before the end of each statement and remove the node from
the active list. However this assumption is not correct in all cases(e.g. call
'CREATE TEMPORARY TABLE myisam_t SELECT * FROM innodb_t' in a transaction
and delete all temporary tables automatically when a session closed),
and can cause the memory allocated for TranxNode be freed
before it was removed from the active list. So The TranxNode pointer in the active
list would become a wild pointer and cause the crash.
After this patch, We have a class called a TranxNodeAllocate which manages the memory
for allocating and freeing TranxNode. It uses my_malloc to allocate memory.
sql/rpl_handler.cc:
params are not initialized.
Before this patch, semisync assumed transactions running in parallel
can not be larger than max_connections, but this is not true when
the event scheduler is executing events, and cause semisync run out
of preallocated transaction nodes.
Fix the problem by allocating transaction nodes dynamically.
This patch also fixed a possible deadlock when running UNINSTALL
PLUGIN rpl_semi_sync_master and updating in parallel. Fixed by
releasing the internal Delegate lock before unlock the plugins.
mysql-test/suite/rpl/t/rpl_semi_sync_event.test:
Add test case for bug#49020
plugin/semisync/semisync_master.cc:
Allocating TranxNode dynamically
plugin/semisync/semisync_master.h:
Allocating TranxNode dynamically
sql/rpl_handler.cc:
Unlock plugins after we have released the Delegate lock to avoid possible deadlock when uninstalling semisync master plugin and doing update in parallel.
Add an option to control whether the master should keep waiting
until timeout when it detected that there is no semi-sync slave
available.
The bool option 'rpl_semi_sync_master_wait_no_slave' is 1 by
defalt, and will keep waiting until timeout. When set to 0, the
master will switch to asynchronous replication immediately when
no semi-sync slave is available.
Semi-sync status were not reset by FLUSH STATUS, this was because
all semi-sync status variables are defined as SHOW_FUNC and FLUSH
STATUS could only reset SHOW_LONG type variables.
This problem is fixed by change all status variables that should
be reset by FLUSH STATUS from SHOW_FUNC to SHOW_LONG.
After the fix, the following status variables will be reset by
FLUSH STATUS:
Rpl_semi_sync_master_yes_tx
Rpl_semi_sync_master_no_tx
Note: normally, FLUSH STATUS itself will be written into binlog
and be replicated, so after FLUSH STATS, one of
Rpl_semi_sync_master_yes_tx
Rpl_semi_sync_master_no_tx
can be 1 dependent on the semi-sync status. So it's recommended
to use FLUSH NO_WRITE_TO_BINLOG STATUS to avoid this.
Semi-sync uses an extra connection from slave to master to send
replies, this is a normal client connection, and used a normal
SET query to set the reply information on master, which is visible
to user and may cause some confusion and complaining.
This problem is fixed by using the method of sending reply by
using the same connection that is used by master dump thread to
send binlog to slave. Since now the semi-sync plugins are integrated
with the server code, it is not a problem to use the internal net
interfaces to do this.
The master dump thread will mark the event requires a reply and
wait for the reply when the event just sent is the last event
of a transaction and semi-sync status is ON; And the slave will
send a reply to master when it received such an event that requires
a reply.
On sparc, semisync master/slave status is always showed as OFF, this
is fixed by change rpl_semisync_master/slave_status variables from
long to char.
plugin/semisync/semisync_master.cc:
Change rpl_semisync_master_status variables from long to char
plugin/semisync/semisync_master.h:
Change rpl_semisync_master_status variables from long to char
plugin/semisync/semisync_slave.cc:
Change rpl_semisync_slave_status variables from long to char
plugin/semisync/semisync_slave.h:
Change rpl_semisync_slave_status variables from long to char
