CHECK_SIMPLE_EQUALITY
PROBLEM:
Crash in "check_simple_equality" when using a subquery with "IN" and
"ALL" in prepare.
ANALYSIS:
Crash can be reproduced using a simplified query like this one:
prepare s from "select 1 from g1 where 1 < all (
select @:=(1 in (select 1 from g1)) from g1)";
This bug is currently present only on 5.5.and 5.1. Its fixed as part
of work log(#1110) in 5.6. We are taking one change to fix this
in 5.5 and 5.1.
Problem seems to be present because we are trying to evaluate "is_null"
on an argument which is part of a subquery
(In Item_is_not_null_test::update_used_tables()).
But the condition to evaluate is only when we do not have a sub query
present, which means to say that "with_subselect" is not set.
With respect to the above query, we create an object of type
"Item_in_optimizer" which by definition is always associated with a
subquery. While in 5.6 we set "with_subselect" to true for
"Item_in_optimizer" object, we do not do the same in 5.5. This results in
the evaluation for "is_null" resulting in a coredump.
So, we are now setting "with_subselect" to true for "Item_in_optimizer"
in 5.1 and 5.5.
mysql-test/r/func_in.result:
Result file changes for the test case added
mysql-test/t/func_in.test:
Test case added for Bug#13012483
sql/item_cmpfunc.h:
Changed Item_in_optimizer::Item_in_optimizer( ) to set "with_subselect"
to true
If a query's end time is before before its start time, the system clock has been turn back
(daylight savings time etc.). When the system clock is changed, we can't tell for certain a
given query was actually slow. We did not protect against logging such a query with a bogus
execution time (resulting from end_time - start_time being negative), and possibly logging it
even though it did not really take long to run.
We now have a sanity check in place.
sql/sql_parse.cc:
Make sure end time is not before start time - otherwise, we can be SURE the system clock
was changed in between, but not by how much. In other words, when the clock is changed,
we don't know how long a query ran, and whether it was slow.
BUG#13519696 - 62940: SELECT RESULTS VARY WITH VERSION AND
WITH/WITHOUT INDEX RANGE SCAN
BUG#13453382 - REGRESSION SINCE 5.1.39, RANGE OPTIMIZER WRONG
RESULTS WITH DECIMAL CONVERSION
BUG#13463488 - 63437: CHAR & BETWEEN WITH INDEX RETURNS WRONG
RESULT AFTER MYSQL 5.1.
Those are all cases where the range optimizer got it wrong
with > and >=.
mysql-test/r/range.result:
Without the code fix for DECIMAL, "select count(val) from t2 where val > 0.1155"
(which uses a range scan) returned 127 instead of 128);
Moreover, both
select * from t1 force index (primary) where a=1 and c>= 2.9;
and
select * from t1 force index (primary) where a=1 and c> 2.9;
would miss "1 1 3".
Without the code fix for strings, both
SELECT * FROM t1 WHERE F1 >= 'A ';
and
SELECT * FROM t1 WHERE F1 BETWEEN 'A ' AND 'AAAAA';
would miss "A A A".
sql/item.cc:
Preamble to the explanations below: opt_range.cc:get_mm_leaf() does
this (this is not changed by the patch): changes
column > value
to
column OP V
where:
* V is what is in "column" after we stored "value" in it
(such store operation may have done rounding...)
* OP is > or >=, depending on what's correct.
For example, if c is an INT column,
c > 2.9 is changed to
c OP 3
where OP is >= ('>' would not be correct).
The bugs below are cases where we chose OP wrongly.
Note that such transformations are visible in the optimizer trace.
1) Fix for STRING. In the scenario with CHAR(5) in range.test, this happens,
in get_mm_tree(), for the condition F1>='A ':
* value->save_in_field_no_warnings(field, 1) wants to store the right argument
(named 'item') into the CHAR(5) field; this stores 'A ' (the item's value)
padded with spaces (which changes nothing: still 'A ')
* we come to
case Item_func::GE_FUNC:
/* Don't use open ranges for partial key_segments */
if ((!(key_part->flag & HA_PART_KEY_SEG)) &&
(stored_field_cmp_to_item(param->thd, field, value) < 0))
tree->min_flag= NEAR_MIN;
tree->max_flag=NO_MAX_RANGE;
What this wants to do is: if the field's value is strictly smaller
than the item's, then ">=" can be changed to ">" (this is an optimization,
it can help pruning one useless partition).
* stored_field_cmp_to_item() is called; it compares the field's
and item's values: the item's value (Item_string::val_str()) is
'A ') and the field's value (Field_string::val_str()) is
'A' (yes val_str() removes end spaces unless sql_mode='PAD_CHAR_TO_FULL_LENGTH');
and the comparison is done with stringcmp() which considers
end spaces as relevant; as end spaces differ, function returns a
negative number, and ">='A '" becomes ">'A'" (i.e. the NEAR_MIN
flag is turned on).
During execution the index range scan code will search for "A", find
a match, but exclude it (because of ">"), wrongly.
The badness is the string comparison done by stored_field_cmp_to_item():
we use the reply of this function to determine where the index search
should start, so it should do comparison like index search does
comparisons; index search comparisons are ha_key_cmp() which uses
a collation-aware comparison (in our case, my_strnncollsp_simple(),
which ignores end spaces); so stored_field_cmp_to_item()
needs to do the same. When this is fixed, condition becomes
">='A '".
2) Fix for DECIMAL: just like in other comparisons in stored_field_cmp_to_item(),
we must first pass the field and then the item; otherwise expectations
on what <0 and >0 mean (inferiority, superiority) get violated.
In the test in range.test about c>2.9: c is an INT column, so 2.9
gets stored as 3, then stored_field_cmp_to_item() compares 3
and 2.9; because of the wrong order of arguments passed
to my_decimal_cmp(), range optimizer
thinks that 3 is < 2.9 and thus changes "c> 2.9" to "c> 3".
After fixing the order, it changes to the correct "c>= 3".
In the test in range.inc for val > 0.1155, it was changed to
val > 0.116, now it is changed to val >= 0.116.
- Reverting the patch for Bug # 12584302
The patch will be reverted in 5.1 and 5.5.
The patch will not be reverted in 5.6, the change will
be properly documented in 5.6.
- Backporting DBUG_ASSERT not to crash on '0000-01-00'
(already fixed in mysql-trunk (5.6))
If init_command was incorrect, we couldn't let users execute
queries, but we couldn't report the issue to the client either
as it does not expect error messages before even sending a
command. Thus, we simply disconnected them without throwing
a clear error.
We now go through the proper sequence once (without executing
any user statements) so we can report back what the problem
is. Only then do we disconnect the user.
As always, root remains unaffected by this as init_command is
(still) not executed for them.
mysql-test/r/init_connect.result:
We now report a proper error if init_command fails.
Expect as much.
mysql-test/t/init_connect.test:
We now report a proper error if init_command fails.
Expect as much.
sql/sql_connect.cc:
If init_command fails, throw an error explaining this to
the user.
SMALL KEY CACHE
The server crashed on division by zero because the key cache was not
initialized and the block length was 0 which was used in a division.
The fix was to not allow CACHE INDEX if the key cache was not initiallized.
Thus never try LOAD INDEX INTO CACHE for an uninitialized key cache.
Also added some windows files/directories to .bzrignore.
handle_segfault is the signal handler code of mysqld. however, it makes
calls to potentially unsafe functions localtime_r, fprintf, fflush.
include/my_stacktrace.h:
Add safe versions of itoa() write() and snprintf().
libmysqld/CMakeLists.txt:
Move signal handler to separate file.
mysys/stacktrace.c:
Remove unsafe function calls.
sql/CMakeLists.txt:
Move signal handler to separate file.
sql/Makefile.am:
Move signal handler to separate file.
sql/mysqld.cc:
Move signal handler to separate file.
sql/signal_handler.cc:
Remove unsafe function calls.
readline.cc: In function char* batch_readline(LINE_BUFFER*):
readline.cc:60:9: error: out_length may be used uninitialized in this function
log.cc: In function int find_uniq_filename(char*):
log.cc:1857:8: error: number may be used uninitialized in this function
a.k.a. Bug#7975 deadlock without any locking, simple select and update
Bug#7975 was reintroduced when the storage engine API was made
pluggable in MySQL 5.1. Instead of looking at thd->lex directly, we
rely on handler::extra(). But, we were looking at the wrong extra()
flag, and we were ignoring the TRX_DUP_REPLACE flag in places where we
should obey it.
innodb_replace.test: Add tests for hopefully all affected statement
types, so that bug should never ever resurface. This kind of tests
should have been added when fixing Bug#7975 in MySQL 5.0.3 in the
first place.
rb:806 approved by Sunny Bains
PARENT FOR OTHER ONE
Do not try to lookup key_nr'th key in 'table' because there may not be such
a key there. key_nr is the number of the key in the _child_ table name, not
in the parent table.
Instead just print the fields of the record that are covered by the first key
defined on the parent table.
This bug gets a better fix in MySQL 5.6, which is too risky for 5.1 and 5.5.
Approved by: Jon Olav Hauglid (via IM)
Buffer over-run on all platforms, crash on windows, wrong result on other platforms,
when rounding numbers which start with 999999999 and have
precision = 9 or 18 or 27 or 36 ...
mysql-test/r/type_newdecimal.result:
New test cases.
mysql-test/t/type_newdecimal.test:
New test cases.
sql/my_decimal.h:
Add sanity checking code, to catch buffer over/under-run.
strings/decimal.c:
The original initialization of intg1 (add 1 if buf[0] == DIG_MAX)
will set p1 to point outside the buffer, and the loop to copy the original value
while (buf0 < p0)
*(--p1) = *(--p0);
will overwrite memory outside the my_decimal object.
A buffer large enough to hold the query _plus_ some additional
data is allocated before parsing is started. The additional data
is used by the query cache, and consists of the name of the current
database and a set of flags.
When a packet containing multiple SQL statements is sent to the
server and one of the statements changes the current database
(a "USE <db>" statement), and the name of the new current database
is longer than of the previous, there is not enough space in the
buffer for the new name, and we write out over the buffer boundary.
The fix adds an extra field to store the number of bytes
allocated to the database name in the buffer. If the current
database name changes, and the new name is longer than the
previous one, we refuse to cache the query.
Problematic query:
insert ignore into `t1_federated` (`c1`) select `c1` from `t1_local` a
where not exists (select 1 from `t1_federated` b where a.c1 = b.c1);
When this query is killed in another connection it could lead to crash.
The problem is follwing:
An attempt to obtain table statistics for subselect table in killed query
fails with an error. So JOIN::optimize() for subquery is failed but
it does not prevent further subquery evaluation.
At the first subquery execution JOIN::optimize() is called
(see subselect_single_select_engine::exec()) and fails with
an error. 'executed' flag is set to TRUE and it prevents
further subquery evaluation. At the second call
JOIN::optimize() does not happen as 'JOIN::optimized' is TRUE
and in case of uncacheable subquery the 'executed' flag is set
to FALSE before subquery evaluation. So we loose 'optimize stage'
error indication (see subselect_single_select_engine::exec()).
In other words 'executed' flag is used for two purposes, for
error indication at JOIN::optimize() stage and for an
indication of subquery execution. And it seems it's wrong
as the flag could be reset.
mysql-test/r/error_simulation.result:
test case
mysql-test/t/error_simulation.test:
test case
sql/item_subselect.cc:
added new flag subselect_single_select_engine::optimize_error
which is used for error detection which could happen at optimize
stage.
sql/item_subselect.h:
added new flag subselect_single_select_engine::optimize_error
sql/sql_select.cc:
test case
1 - If a user had SHOW VIEW and SELECT privileges on a view and
this view was referencing another view, EXPLAIN SELECT on the outer
view (that the user had privileges on) could reveal the structure
of the underlying "inner" view as well as the number of rows in
the underlying tables, even if the user had privileges on none of
these referenced objects.
This happened because we used DEFINER's UID ("SUID") not just for
the view given in EXPLAIN, but also when checking privileges on
the underlying views (where we should use the UID of the EXPLAIN's
INVOKER instead).
We no longer run the EXPLAIN SUID (with DEFINER's privileges).
This prevents a possible exploit and makes permissions more
orthogonal.
2 - EXPLAIN SELECT would reveal a view's structure even if the user
did not have SHOW VIEW privileges for that view, as long as they
had SELECT privilege on the underlying tables.
Instead of requiring both SHOW VIEW privilege on a view and SELECT
privilege on all underlying tables, we were checking for presence
of either of them.
We now explicitly require SHOW VIEW and SELECT privileges on
the view we run EXPLAIN SELECT on, as well as all its
underlying views. We also require SELECT on all relevant
tables.
mysql-test/r/view_grant.result:
add extensive tests to illustrate desired behavior and
prevent regressions (as always).
mysql-test/t/view_grant.test:
add extensive tests to illustrate desired behavior and
prevent regressions (as always).
sql/sql_view.cc:
We no longer run the EXPLAIN SUID (with DEFINER's privileges).
To achieve this, we use a temporary, SUID-less TABLE_LIST for
the views while checking privileges.
SYSTEM VARIABLE NAME SQL_MAX_JOIN_SI
BACKGROUND:
ER_TOO_BIG_SELECT refers to SQL_MAX_JOIN_SIZE, which is the
old name for MAX_JOIN_SIZE.
FIX:
Support for old name SQL_MAX_JOIN_SIZE is removed in MySQL 5.6
and is renamed as MAX_JOIN_SIZE.So the errmsg.txt
and mysql.cc files have been updated and the corresponding result
files have also been updated.
The main problem was that lex_start() was forgotten to be called before processing
COM_REFRESH.
Another problem discovered was that if failures to flush the error log were not properly
handled, which resulted in the server crash.
The user-visible effect of these problems were:
- if COM_REFRESH command was sent after SQL-queries of some sort,
the server would crash.
- if COM_REFRESH was requested with REFRESH_LOG only, and the error log
failed to flush, the server would crash. The error log fails to flush
when it points to unavailable file (for example, due to restricted
permissions).
The fixes are:
- call lex_start() in the beginning of COM_REFRESH;
- handle failures to flush the error log properly, i.e. raise ER_UNKNOWN_ERROR.
sql/sql_parse.cc:
Fix for Bug#13001491: MYSQL_REFRESH CRASHES WHEN STORED ROUTINES ARE RUN CONCURRENTLY.
tests/mysql_client_test.c:
A test case for Bug#13001491: MYSQL_REFRESH CRASHES WHEN STORED ROUTINES
ARE RUN CONCURRENTLY.
GROUPING BY FUNCTIONS.... (PART
The bug was introduced in a patch for bug 49897.
Problem: The assertion inserted by the original patch to guard against
zero-lenght sort keys during merge phase triggers also when the whole
set fits in memory.
Fix: Move assert so that it does not trigger if the whole set is in
memory.
mysql-test/r/group_by.result:
Add test for bug#11765254
mysql-test/t/group_by.test:
Add test for bug#11765254
sql/filesort.cc:
Move assertion
Converting the number zero to binary and back yielded the number zero,
but with no digits, i.e. zero precision.
This made the multiply algorithm go haywire in various ways.
include/decimal.h:
Document struct st_decimal_t
mysql-test/r/type_newdecimal.result:
New test case (valgrind warnings)
mysql-test/t/type_newdecimal.test:
New test case (valgrind warnings)
sql/my_decimal.h:
Remove the HAVE_purify enabled/disabled code.
strings/decimal.c:
Make a proper zero, with non-zero precision.
Suppress the known warnings generated by filesort().
The real fix belongs to worklog 1509:
Pack values of non-sorted fields in the sort buffer
(which is basically the same issue, but in an optimization context:
We are writing the entire sort buffer to disk,
including un-used space for varchar columns.)
mysql-test/valgrind.supp:
Add new Memcheck suppressions for filesort.
sql/filesort.cc:
Remove the ifdef HAVE_purify/bzero code, use valgrind suppressions instead.
Background: Backporting fix for BUG 11752963 to Mysql5.1 branch.
Problem: Fix of bug 11752963 was only available for trunk and 5.5 branch.
Partial fix has been pushed to 5.1 branch as well.
Fix: backporting the fixes of bug 11752963 to 5.1 branch.
1. Made all major changes to make 5.1 branch in line with 5.5 and the trunk.
2. skipped the partial patch that was already applied to the 5.1 branch.
sql/rpl_rli.h:
Made inited Volatile (find inline comments)
sql/slave.cc:
backported all changes from the fix of BUG#11752963.
PARTITONING, ON INDEX CREATE
If the first partition succeeded in adding a index, but a successive partition failed,
then the first partition had still the new index.
The fix reverts the added indexes from previous partitions on failure.
CRASHES SERVER
Flushing of MERGE table or one of its child tables, which was
locked by flushing thread using LOCK TABLES, might have caused
crashes or assertion failures if the thread failed to reopen
child or parent table.
Particularly, this might have happened when another connection
killed this FLUSH TABLE statement/connection.
Also this problem might have occurred when we failed to reopen
MERGE table or one of its children when executing DDL statement
under LOCK TABLES.
The problem was caused by the fact that reopen_tables() might
have failed to reopen child table but still tried to reopen,
reattach children for and re-lock its parent. Vice versa it
might have failed to reopen parent but kept references from
children to parent around. Since reopen_tables() closes table
it has failed to reopen and therefore frees all associated
memory such dangling references led to crashes when followed.
This patch solves this problem by ensuring that we always close
parent table and all its children if we fail to reopen this
table or one of its children. Same happens if we fail to reattach
children to parent.
Affects 5.1 only.
mysql-test/r/merge.result:
A test case for BUG#11763712.
mysql-test/t/merge.test:
A test case for BUG#11763712.
sql/sql_base.cc:
When flushing tables under LOCK TABLES, all locked
and flushed tables are released and then reopened.
It may happen that we failed to reopen some tables,
in this case we reopen as much tables as possible.
If it was not possible to reopen MERGE child, MERGE
parent is unusable and must be removed from thread
open tables list.
If it was not possible to reopen MERGE parent, all
MERGE child table objects are unusable as well, at
least because their locks are handled by MERGE parent.
They must also be removed from thread open tables
list.
In other words if it was impossible to reopen any
object of a MERGE table or reattach child tables,
all objects of this MERGE table must be considered
unusable and closed.
There is an optimization of DISTINCT in JOIN::optimize()
which depends on THD::used_tables value. Each SELECT statement
inside SP resets used_tables value(see mysql_select()) and it
leads to wrong result. The fix is to replace THD::used_tables
with LEX::used_tables.
mysql-test/r/sp.result:
test case
mysql-test/t/sp.test:
test case
sql/sql_base.cc:
THD::used_tables is replaced with LEX::used_tables
sql/sql_class.cc:
THD::used_tables is replaced with LEX::used_tables
sql/sql_class.h:
THD::used_tables is replaced with LEX::used_tables
sql/sql_insert.cc:
THD::used_tables is replaced with LEX::used_tables
sql/sql_lex.cc:
THD::used_tables is replaced with LEX::used_tables
sql/sql_lex.h:
THD::used_tables is replaced with LEX::used_tables
sql/sql_prepare.cc:
THD::used_tables is replaced with LEX::used_tables
sql/sql_select.cc:
THD::used_tables is replaced with LEX::used_tables
The problem is that TIME_FUZZY_DATE is explicitly used for get_arg0_date()
function in Item_date_typecast::get_date method. The fix is to use real
fuzzy_date value.
mysql-test/r/func_time.result:
test case
mysql-test/t/func_time.test:
test case
sql/item_timefunc.cc:
use real fuzzy_date value
