freezes (win) the server
The check for equality was assuming the field object is always
created. If it's not it was de-referencing a NULL pointer.
Fixed to use the data in the create object instead.
If first call of the procedure is failed on
the open_table stage stmt_arena->state is set to
EXECUTED state. On second call(if no errors on
open_table stage) it leads to use of worng memory arena
in find_field_in_view() function as
thd->stmt_arena->is_stmt_prepare_or_first_sp_execute()
returns FALSE for EXECUTED state. The item is created
not in its own arena and it leads to crash on further
calls of the procedure.
The fix:
change state of arena only if
no errors on open_table stage happens.
Bug#35589 SET PASSWORD caused a crash
Bug#35591 FLUSH PRIVILEGES caused a crash
A race condition on the privilege hash tables (proc_priv_hash
and func_priv_hash) caused one thread to try to delete elements
that had already been deleted by another thread.
The bug was caused by reading and saving the pointers to
the hash tables outside mutex protection. This led to an
inconsistency where a thread copied a pointer to a hash,
another thread did the same, the first thread then deleted
the hash, and the second then crashed when it in turn tried to
delete the deleted hash.
The fix is to ensure that operations on the shared hash structures
happens under mutex protection (moving the locking up a little)
when replicating
The function create_virtual_tmp_table does not
set db_low_byte_first in the same way as
create_tmp_table does, causing copying from
the virtual table to a real table to get strange
values for SET types on big-endian machines.
The slave thread changed the format of the information it used to
connect to the master after patch for BUG 13963. This resulted
in old master getting confused, thence rejecting the slave
connection attempt.
In particular, patch for BUG 13963 removed the rpl_recovery_rank
variable which was, at that time, packed together with the rest
of the information which the slave would use to register itself
on the master. Based on this data, the master would then assert
that the number of bytes received in the connection command was
consistent to what it was expecting.
Therefore, given that a slave, patched with the aforementioned
patch, would not pack the four bytes related to the
rpl_recovery_rank variable, the old master would reject the
connection attempt. It would assume that the data was
inconsistent (fewer bytes than it was expecting) and return
an error.
We fix this by faking an rpl_recovery_rank variable when
registering the slave on the master. In practice this reverts a
small part of patch for BUG 13963, the one related to the slave
connecting to the master.
The problem is a somewhat common misusage of the strmake function.
The strmake(dst, src, len) function writes at most /len/ bytes to
the string pointed to by src, not including the trailing null byte.
Hence, if /len/ is the exact length of the destination buffer, a
one byte buffer overflow can occur if the length of the source
string is equal to or greater than /len/.
MYSQL_ADD_EXECUTABLE will instructs CPack where to install the exe. On Windows, it also
adds version resource and if -DSIGNCODE was given, will sign the exe in packaging step.
If the handler (or delayed insert) thread failed to lock a table due
to being killed, the "dead" flag was used to notify the connection thread
of this failure. However, with the changes introduced by Bug#45949,
the handler thread will no longer try to lock the table if it was killed.
This meant that the "dead" flag would not be set, and the connection
thread would not notice that the handler thread had failed.
This could happen with concurrent INSERT DELAYED and FLUSH TABLES.
FLUSH TABLES would kill any active INSERT DELAYED that had opened any
table(s) to be flushed. This could cause the INSERT DELAYED connection
thread to be stuck waiting for the handler thread to lock its table,
while the handler thread would be looping, trying to get the connection
thread to notice the error.
The root of the problem was that the handler thread had both the "dead"
flag and "thd->killed" to indicate that it had been killed. Most places
both were set, but some only set "thd->killed". And
Delayed_insert::get_local_table() only checked "dead" while waiting for
the table to be locked.
This patch removes the "dead" variable and replaces its usage with
"thd->killed", thereby resolving the issue.
When compressed myisam files are opened, they are always memory mapped
sometimes causing memory swapping problems.
When we mmap the myisam compressed tables of size greater than the memory
available, the kswapd0 process utilization is very high consuming 30-40% of
the cpu. This happens only with linux kernels older than 2.6.9
With newer linux kernels, we don't have this problem of high cpu consumption
and this option may not be required.
The option 'myisam_mmap_size' is added to limit the amount of memory used for
memory mapping of myisam files. This option is not dynamic.
The default value on 32 bit system is 4294967295 bytes and on 64 bit system it
is 18446744073709547520 bytes.
Note: Testcase only tests the option variable. The actual bug has be to
tested manually.
returns incorrect results with where
An outer join of a const table (outer) and a normal table
(inner) with GROUP BY on a field from the outer table would
optimize away GROUP BY, and thus trigger the optimization to
do away with a temporary table if grouping was performed on
columns from the const table, hence executing the query with
filesort without temporary table. But this should not be
done if there is a non-indexed access to the inner table,
since filesort does not handle joins. It expects either ref
access, range ditto or table scan. The join condition will
thus not be applied.
Fixed by always forcing execution with temporary table in
the case of ROLLUP with a query involving an outer join. This
is a slightly broader class of queries than need fixing, but
it is hard to ascertain the position of a ROLLUP field wrt
outer join with current query representation.
Problem: inserting a record we don't set unused null bits in the
record buffer if no default field values used.
That may lead to wrong live checksum calculation.
Fix: set unused null bits in the record buffer in such cases.
The reason for the deadlock was an improper exit from
MDL_context::wait_for_locks() which caused mysys_var->current_mutex to remain
LOCK_mdl even though LOCK_mdl was no longer held by that connection.
This could for example lead to a deadlock in the following way:
1) INSERT DELAYED tries to open a table but fails, and trying to recover it
calls wait_for_locks().
2) Due to a pending exclusive request, wait_for_locks() fails and exits without
resetting mysys_var->current_mutex for the delayed insert handler thread. So it
continues to point to LOCK_mdl.
3) The handler thread manages to open a table.
4) A different connection takes LOCK_open and tries to take LOCK_mdl.
5) FLUSH TABLES from a third connection notices that the handler thread has a
table open, and tries to kill it. This involves locking mysys_var->current_mutex
while having LOCK_open locked. Since current_mutex mistakenly points to LOCK_mdl,
we have a deadlock.
This patch makes sure MDL_EXIT_COND() is called before exiting wait_for_locks().
This clears mysys->current_mutex which resolves the issue.
An assert is added to recover_from_failed_open_table_attempt() after
wait_for_locks() is called, to check that current_mutex is indeed reset.
With this assert in place, existing tests in (e.g.) mdl_sync.test will fail
without this patch.
