During REPAIR TABLE of a MyISAM table, a temporary data file (.TMD)
is created. When repair finishes, this file is renamed to the original
.MYD file. The problem was that during this rename, we copied the
stats from the old file to the new file with chmod/chown. If a user
managed to replace the temporary file before chmod/chown was executed,
it was possible to get an arbitrary file with the privileges of the
mysql user.
This patch fixes the problem by not copying stats from the old
file to the new file. This is not needed as the new file was
created with the correct stats. This fix only changes server
behavior - external utilities such as myisamchk still does
chmod/chown.
No test case provided since the problem involves synchronization
with file system operations.
Argument to malloc-lib must be included in restricted list of
directories, symlink guards added, and mysqld and mysqld-version
options restricted to command line only. Don't redirect errors to
stderr.
Problem:
When build_equal_items_for_cond gets called for a big query
recursively, the specified thread_stack_size exceeds. But
optimizer does not handle this condition. As a result, server
exits.
Solution:
Check if we exceed specified stack size and if yes exit
gracefully by throwing an error.
Reexecution of prepared "ANALYZE TABLE merge_table, table" may miss to
reinitialize "table" for subsequent execution and trigger assertion failure.
This happens because MERGE engine may adjust table->next_global chain, which
gets cleared by close_thread_tables()/ha_myisammrg::detach_children() later.
Since reinitilization iterates next_global chain, it won't see tables following
merge table.
Fixed by appending saved next_global chain after merge children.
Fix memory barrier issues on releasing mutexes. We must have a full
memory barrier between releasing a mutex lock and reading its waiters.
This prevents us from missing to release waiters due to reading the
number of waiters speculatively before releasing the lock. If threads
try and wait between us reading the waiters count and releasing the
lock, those threads might stall indefinitely.
Also, we must use proper ACQUIRE/RELEASE semantics for atomic
operations, not ACQUIRE/ACQUIRE.
a correct fix:
* store properly quoted table names in tables4repair/etc lists
* tell handle_request_for_tables whether the name is aalready properly quoted
* test cases for all uses of fix_table_name()
We assume all around the code that null_value==true is in sync
with NULL value returned by val_str()/val_decimal().
Item_sum_sum::val_decimal() erroneously returned a non-NULL value together
with null_value set to true. Fixing to return NULL instead.
It happens when you are trying to read two or more log files from a
remote server using mysqlbinlog utility.
The reason for this is no matching mysql_close() that concludes the
life time of 'mysql' struct describing connection to the server.
This happens when mysqlbinlog is invoked with connecting to the server
and requesting more than one binlog file. In such case
dump_remote_log_entries() keeps calling safe_connect() per eachfile,
never caring to invoke mysql_close(). Only the final safe_connect()'s
allocation effect are cleaned by the base code.
That is with 2 files there's one 'mysql' connection descriptor struct
uncleaned/deallocated.
We are backporting the bug 21255763 (pushed in mysql-trunk)
in the earlier version of MySQL starting from 5.5 to 5.7.
which was pushed in mysql-trunk.
Fix:
Invoke mysql_close() just before mysql_init() in safe_connect()
defined in mysqlbinlog.cc. That makes possibly previously used 'mysql' be
reclaimed prior a new one is allocated.
Shared variables of Delayed_insert may be updated without mutex protection
when delayed insert thread gets an error.
Re-acquire mutex earlier, so that shared variables are protected.
ISSUE: Queries with mediumint as column when operated with
long long type of data results in buffer overflow in
store_long function.
The merging rule specified for (MYSQL_TYPE_LONGLONG
MYSQL_TYPE_INT24) is MYSQL_TYPE_LONG. Due to this store_long
function was getting called which resulted in buffer overflow.
SOLUTION:
The correct merging rule for (MYSQL_TYPE_LONGLONG,
MYSQL_TYPE_INT24) should be MYSQL_TYPE_LONGLONG.
So, instead of function store_long, function store_longlong
is called which correctly handles the type MYSQL_TYPE_LONGLONG.
External Bug #23645238 is a duplicate of this issue.
DERIVED TABLE IN JOIN
ISSUE:
------
This problem occurs under the following conditions:
1) A parameter is used in the select-list of a derived table.
2) The derived table is part of a JOIN.
SOLUTION:
---------
When a derived table is materialized, a temporary table is
created. This temporary table creates a field each for the
items in the select-list of the derived table. This set of
fields is later used to setup the join.
Currently no field is created in the temporary table if a
parameter is used in the select-list.
Create a field for the parameter. By default Item_param's
result type in a prepared statement is set to
STRING_RESULT. This can change during the execute phase
depending on the user variable. But since the execute phase
creates its own temporary table, it will be handled
separately.
This is a backport of the fix for BUG#22392374.
Fix get_quick_keys(): When building range tree from a condition
in form
keypart1=const AND (keypart2 < 0 OR keypart2>=0)
the SEL_ARG for keypart2 represents an interval (-inf, +inf).
However, the logic that sets UNIQUE_RANGE flag fails to recognize
this, and sets UNIQUE_RANGE flag if (keypart1, keypart2) covered
a unique key.
As a result, range access executor assumes the interval can have
at most one row and only reads the first row from it.
Problem:
In debug builds, there is a chance that an out-of-bounds
read is performed when tables are locked in
LTM_PRELOCKED_UNDER_LOCK_TABLES mode. It can happen because
the debug code uses enum values as index for an array of
mode descriptions, but it only takes into consideration 3
out of 4 of the enum values.
Fix:
This patch fixes it by implementing a getter for the enum which
returns a string representation of the enum,
effectively removing the out-of-bounds read.
Moreover, it also fixes the lock mode descriptions that
would be print out in debug builds.
Commit#ebd24626ca38e7fa1e3da2acdcf88540be70fabe obsoleted the THREAD and
THREAD_SAFE_CLIENT preprocessor symbols. This is not removed in the
sql/net_serv.cc thereby the code that retries on EINTR became dead code.
Remove the THREAD_SAFE_CLIENT preprocessor directive form sql/net_serv.cc.
Also check errno for EINTR only if there is an error in preceding read call.
GET_SERVER_FROM_TABLE_TO_CACHE
Description:- Server received SIG11 in the function,
"get_server_from_table_to_cache()".
Analysis:- Defining a server with a blank name is not
handled properly.
Fix:- Modified "get_server_from_table_to_cache()" to
take care of blank server name.
FROM I_S
Issue:
------
There is a difference in the field type created when the
following DDLs are used:
1) CREATE TABLE t0 AS SELECT NULL;
2) CREATE TABLE t0 AS SELECT GREATEST(NULL,NULL);
The first statement creates field of type Field_string and
the second one creates a field of type Field_null.
This creates a problem when the query mentioned in this bug
is used. Since the null_ptr is calculated differently for
Field_null.
Solution:
---------
When there is a function returning null in the select list
as mentioned above, the field should be of type
Field_string.
This was fixed in 5.6+ as part of Bug#14021323. This is a
backport to mysql-5.5.
An incorrect comment in innodb_bug54044.test has been
corrected in all versions.
ASSERTION `0' FAILED ON SELECT AREA
Problem:
Optimizer tries to get the points to calculate area without
checking the return value of uint4korr for 0 "points". As a
result server exits.
Solution:
Check the return value from uint4korr().
