Analysis: For some reason table stats for a table pointed from a index
is not initialized. Added additional warning output on this situation
and table stats initialization. This is better than asserting.
than with InnoDB plugin
Fix: os0file.h in XtraDB had OS_AIO_N_PENDING_IOS_PER_THREAD 256
when on InnoDB it is OS_AIO_N_PENDING_IOS_PER_THREAD 32. Changed
XtraDB also to use 32.
WITH CERTAIN MAX_HEAP_TABLE_SIZE VALUES
Description:
When the system variable 'max_heap_table_size'
is set to 20GB, the server crashes on creation of a
temporary tables or tables using MEMORY storage engine.
Analysis:
The variable 'max_record' determines the amount heap
allocated for the records of the table. This value
is determined using the 'max_heap_table_size' variable.
'records_in_block' in turn uses the max_records to
determine the number of records per block.
When the 'max_heap_table_size' is set to 20GB, then
the 'records_in_block' is calculated to a value of
2^28.
The size of the block determined by multiplying the
'records_in_block' and 'recbuffer' results in overflow
and hence the value becomes zero. As a result, zero bytes
of the heap is allocated for the table. This will
result in a server crash when the table is accessed.
Fix:
The variables 'records_in_block' and 'recbuffer' are
typecasted to 'unsigned long' while calculating the
size of the block.
* Introduce a set of PLUGIN_xxx cmake options with values
NO, STATIC, DYNAMIC, AUTO, YES (abort if plugin is not compiled)
* Deprecate redundant and ambiguous WITH_xxx, WITH_PLUGIN_xxx,
WITH_xxx_STORAGE_ENGINE, WITHOUT_xxx, WITHOUT_PLUGIN_xxx,
WITHOUT_xxx_STORAGE_ENGINE
* Actually check whether a plugin is disabled (DISABLED keyword was
always present, but it was ignored until now).
* Support conditionally disabled plugins - keyword ONLY_IF
* Use ONLY_IF for conditionally skipping plugins, instead of
doing MYSQL_ADD_PLUGIN conditionally as before. Because if
MYSQL_ADD_PLUGIN isn't done at all, PLUGIN_xxx=YES cannot work.
mark path-related variables (AIO_LIBRARY, ODBC_LIBRARY, ODBC_INCLUDE_DIR,
Thrift_LIBS, Thrift_INCLUDE_DIRS, CRYPTO_LIBRARY, OPENSSL_LIBRARIES,
OPENSSL_ROOT_DIR, OPENSSL_INCLUDE_DIR) as advanced - paths are
automatically discovered by cmake.
mark few choice variables (ENABLED_LOCAL_INFILE, WITHOUT_SERVER,
DISABLE_SHARED) as not advanced - they are user choices, not automatically
configured values.
remove unused BACKUP_TEST variable.
Auto-generate the allowed list of values for enum/set/flagset options
in --help output. But don't do that when the help text already has them.
Also, remove lists of values from help strings of various options, where
they were simply listed without any additional information.
than with InnoDB plugin
Fix: os0file.h in XtraDB had OS_AIO_N_PENDING_IOS_PER_THREAD 256
when on InnoDB it is OS_AIO_N_PENDING_IOS_PER_THREAD 32. Changed
XtraDB also to use 32.
Analysis: Based on crashed the buffer pool instance identifier is
not correct on block to be freed. Add LRU list mutex holding
on functions calling free and add additional safety checks.
replication causing replication to fail.
Remove the temporary fix for MDEV-5914, which used READ COMMITTED for parallel
replication worker threads. Replace it with a better, more selective solution.
The issue is with certain edge cases of InnoDB gap locks, for example between
INSERT and ranged DELETE. It is possible for the gap lock set by the DELETE to
block the INSERT, if the DELETE runs first, while the record lock set by
INSERT does not block the DELETE, if the INSERT runs first. This can cause a
conflict between the two in parallel replication on the slave even though they
ran without conflicts on the master.
With this patch, InnoDB will ask the server layer about the two involved
transactions before blocking on a gap lock. If the server layer tells InnoDB
that the transactions are already fixed wrt. commit order, as they are in
parallel replication, InnoDB will ignore the gap lock and allow the two
transactions to proceed in parallel, avoiding the conflict.
Improve the fix for MDEV-6020. When InnoDB itself detects a deadlock, it now
asks the server layer for any preferences about which transaction to roll
back. In case of parallel replication with two transactions T1 and T2 fixed to
commit T1 before T2, the server layer will ask InnoDB to roll back T2 as the
deadlock victim, not T1. This helps in some cases to avoid excessive deadlock
rollback, as T2 will in any case need to wait for T1 to complete before it can
itself commit.
Also some misc. fixes found during development and testing:
- Remove thd_rpl_is_parallel(), it is not used or needed.
- Use KILL_CONNECTION instead of KILL_QUERY when a parallel replication
worker thread is killed to resolve a deadlock with fixed commit
ordering. There are some cases, eg. in sql/sql_parse.cc, where a KILL_QUERY
can be ignored if the query otherwise completed successfully, and this
could cause the deadlock kill to be lost, so that the deadlock was not
correctly resolved.
- Fix random test failure due to missing wait_for_binlog_checkpoint.inc.
- Make sure that deadlock or other temporary errors during parallel
replication are not printed to the the error log; there were some places
around the replication code with extra error logging. These conditions can
occur occasionally and are handled automatically without breaking
replication, so they should not pollute the error log.
- Fix handling of rgi->gtid_sub_id. We need to be able to access this also at
the end of a transaction, to be able to detect and resolve deadlocks due to
commit ordering. But this value was also used as a flag to mark whether
record_gtid() had been called, by being set to zero, losing the value. Now,
introduce a separate flag rgi->gtid_pending, so rgi->gtid_sub_id remains
valid for the entire duration of the transaction.
- Fix one place where the code to handle ignored errors called reset_killed()
unconditionally, even if no error was caught that should be ignored. This
could cause loss of a deadlock kill signal, breaking deadlock detection and
resolution.
- Fix a couple of missing mysql_reset_thd_for_next_command(). This could
cause a prior error condition to remain for the next event executed,
causing assertions about errors already being set and possibly giving
incorrect error handling for following event executions.
- Fix code that cleared thd->rgi_slave in the parallel replication worker
threads after each event execution; this caused the deadlock detection and
handling code to not be able to correctly process the associated
transactions as belonging to replication worker threads.
- Remove useless error code in slave_background_kill_request().
- Fix bug where wfc->wakeup_error was not cleared at
wait_for_commit::unregister_wait_for_prior_commit(). This could cause the
error condition to wrongly propagate to a later wait_for_prior_commit(),
causing spurious ER_PRIOR_COMMIT_FAILED errors.
- Do not put the binlog background thread into the processlist. It causes
too many result differences in mtr, but also it probably is not useful
for users to pollute the process list with a system thread that does not
really perform any user-visible tasks...
SLOW/CRASHES SEMAPHORE
Problem:
There are 2 lakh tables - fk_000001, fk_000002 ... fk_200000. All of them
are related to the same parent_table through a foreign key constraint.
When the parent_table is loaded into the dictionary cache, all the child table
will also be loaded. This is taking lot of time. Since this operation happens
when the dictionary latch is taken, the scenario leads to "long semaphore wait"
situation and the server gets killed.
Analysis:
A simple performance analysis showed that the slowness is because of the
dict_foreign_find() function. It does a linear search on two linked list
table->foreign_list and table->referenced_list, looking for a particular
foreign key object based on foreign->id as the key. This is called two
times for each foreign key object.
Solution:
Introduce a rb tree in table->foreign_rbt and table->referenced_rbt, which
are some sort of index on table->foreign_list and table->referenced_list
respectively, using foreign->id as the key. These rbt structures will be
solely used by dict_foreign_find().
rb#5599 approved by Vasil
- Key_value_records_iterator::get_next() should pass pointer to the key
to handler->ha_index_next_same(). Because of a typo bug, pointer-to-pointer
was passed instead in certain cases.
