Symptom:
When the sql function SLEEP() was executed in the slave SQL thread or from an event (as in
CREATE EVENT, not binlog event), then the timeout was capped to 5 seconds.
Background:
This bug was introduced in the fix of BUG#10374, in the function interruptible_wait() in
item_func.cc.
The function interruptible_wait(), called from item_func_sleep::val_int(), splits the
sleep into 5 seconds units. After each unit, it checks if thd->is_connected() is true: if
not, it stops sleeping. The purpose is to not use system resources to sleep when a client
disconnects.
However, thd->is_connected() returns false for the slave SQL thread and for the event
worker thread, because they don't connect to the server the same way as client threads
do.
Fix:
Make thd->is_connected() return true for all system threads.
sql/sql_class.h:
Made THD::is_connected() return true for all system threads.
Problem: Item_str_ascii_func::val_str() did not set
charset of the returned value properly.
mysql-test/include/ctype_numconv.inc
mysql-test/r/ctype_binary.result
mysql-test/r/ctype_cp1251.result
mysql-test/r/ctype_latin1.result
mysql-test/r/ctype_ucs.result
- Adding tests
sql/item_strfunc.cc
- Adding initialization of charset
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.
from mysql-next-mr-opt-backporting.
Bug#54515: Crash in opt_range.cc::get_best_group_min_max on
SELECT from VIEW with GROUP BY
When handling the grouping items in get_best_group_min_max, the
items need to be of type Item_field. In this bug, an ASSERT
triggered because the item used for grouping was an
Item_direct_view_ref (i.e., the group column is from a view).
The fix is to get the real_item since Item_ref* pointing to
Item_field is ok.
mysql-test/r/select.result:
Add test for BUG#54515
mysql-test/t/select.test:
Add test for BUG#54515
sql/opt_range.cc:
Get the real_item() when processing grouping items in
get_best_group_min_max.
from next-mr-bugfixing:
BUG#54682 "set sql_select_limit=0 does not work"; let SQL_SELECT_LIMIT=0
work like it does in 5.1.
mysql-test/suite/sys_vars/r/sql_select_limit_func.result:
before the fix, the SET would emit a warning (0 being rounded up to 1)
and SELECTs would return one row.
sql/sys_vars.cc:
0 is allowed, it means an implicit LIMIT 0 (i.e. no rows returned)
Problem: sha2() reported its result as BINARY
Fix:
- Inheriting Item_func_sha2 from Item_str_ascii_func
- Setting max_length via fix_length_and_charset()
instead of direct assignment.
- Adding tests
Problem: Item_copy did not set "fixed", which resulted in DBUG_ASSERT in some cases.
Fix: adding initialization of the "fixed" member
Adding tests:
mysql-test/include/ctype_numconv.inc
mysql-test/r/ctype_binary.result
mysql-test/r/ctype_cp1251.result
mysql-test/r/ctype_latin1.result
mysql-test/r/ctype_ucs.result
Adding initialization of the "fixed" member:
sql/item.h
value and NO_ZERO_DATE
The problem was that a older version of the error path for a
failed admin statement relied upon a few error conditions being
met in order to access a table handler, the first one being that
the table object pointer was not NULL. Probably due to chance,
in all cases a table object was closed but the reference wasn't
reset, the other conditions didn't evaluate to true. With the
addition of a new check on the error path, the handler started
being dereferenced whenever it was not reset to NULL, causing
problems for code paths which closed the table but didn't reset
the reference.
The solution is to reset the reference whenever a admin statement
fails and the tables are closed.
mysql-test/r/partition_innodb.result:
Add test case result for Bug#54783
mysql-test/t/partition_innodb.test:
Add test case for Bug#54783
sql/sql_table.cc:
In case table recreate failed, set a appropriate result code.
Reset reference to a closed table object, otherwise the error
path might attempt to access it.
large-pages option is broken) from next-mr to trunk-bugfixing.
Original revision:
------------------------------------------------------------
revision-id: vvaintroub@mysql.com-20100416134524-y4v27j90p5xvblmy
parent: luis.soares@sun.com-20100416000700-n267ynu77visx31t
committer: Vladislav Vaintroub <vvaintroub@mysql.com>
branch nick: mysql-next-mr-bugfixing
timestamp: Fri 2010-04-16 15:45:24 +0200
message:
Bug #52716 Large files support is disabled, large-pages option is broken.
Correct typo: large pages option was tied to wrong variable opt_large_files,
instead of opt_large_pages.
------------------------------------------------------------
DROP TEMP TABLE
Cset: alfranio.correia@sun.com-20100420091043-4i6ouzozb34hvzhb
introduced a change that made drop temporary table to be always
logged if current statement log format was set to row. This is
fine. However, logging operations, for a "DROP TABLE" statement
in mysql_rm_table_part2, are not protected by first checking if
the mysql_bin_log is open before proceeding to the actual
logging. They only check the dont_log_query variable. This was
actually uncovered by the aforementioned cset and not introduced
by it.
We fix this by extending the condition used in the "if" that
wraps logging operations in mysql_rm_table_part2.
BUG#54872 MBR: replication failure caused by using tmp table inside transaction
Changed criteria to classify a statement as unsafe in order to reduce the
number of spurious warnings. So a statement is classified as unsafe when
there is on-going transaction at any point of the execution if:
1. The mixed statement is about to update a transactional table and
a non-transactional table.
2. The mixed statement is about to update a temporary transactional
table and a non-transactional table.
3. The mixed statement is about to update a transactional table and
read from a non-transactional table.
4. The mixed statement is about to update a temporary transactional
table and read from a non-transactional table.
5. The mixed statement is about to update a non-transactional table
and read from a transactional table when the isolation level is
lower than repeatable read.
After updating a transactional table if:
6. The mixed statement is about to update a non-transactional table
and read from a temporary transactional table.
7. The mixed statement is about to update a non-transactional table
and read from a temporary transactional table.
8. The mixed statement is about to update a non-transactionala table
and read from a temporary non-transactional table.
9. The mixed statement is about to update a temporary non-transactional
table and update a non-transactional table.
10. The mixed statement is about to update a temporary non-transactional
table and read from a non-transactional table.
11. A statement is about to update a non-transactional table and the
option variables.binlog_direct_non_trans_update is OFF.
The reason for this is that locks acquired may not protected a concurrent
transaction of interfering in the current execution and by consequence in
the result. So the patch reduced the number of spurious unsafe warnings.
Besides we fixed a regression caused by BUG#51894, which makes temporary
tables to go into the trx-cache if there is an on-going transaction. In
MIXED mode, the patch for BUG#51894 ignores that the trx-cache may have
updates to temporary non-transactional tables that must be written to the
binary log while rolling back the transaction.
So we fix this problem by writing the content of the trx-cache to the
binary log while rolling back a transaction if a non-transactional
temporary table was updated and the binary logging format is MIXED.
mysqld-debug.exe in 5.5.3 on windows
Fix:
- Do not rename PDB, install mysqld.pdb matching
mysqld-debug.exe into bin\debug subdirectory
- Stack tracing code will now additionally look in
debug subdirectory of the application directory
for debug symbols.
- Small cleanup in stacktracing code: link with
dbghelp rather than load functions dynamically
at runtime, since dbghelp.dll is always present.
- Install debug binaries with WiX
cmake/install_macros.cmake:
Add optional COMPONENT and PDB_DESTINATION
to INSTALL_DEBUG_TARGET
mysys/stacktrace.c:
If binary is build with DBUG, also look in debug subdirectory
of executable directory. Packaging will put some PDBs there
(e.g bin\mysqld-debug.exe will have corresponding pdb in
bin\debug)
Also some cleanup: do not load dbghelp dynamically, instead
link with it. dbghelp is present on all Windows starting with
XP.
packaging/WiX/CPackWixConfig.cmake:
Install debug binaries
sql/CMakeLists.txt:
Do not rename PDB for mysqld-debug.exe, install it in debug subdirectory
switching binlog format to ROW
BUG 52616 fixed the case which the user would switch from STMT to
ROW binlog format, but the server would silently ignore it. After
that fix thd->is_current_stmt_binlog_format_row() reports correct
value at logging time and events are logged in ROW (as expected)
instead of STMT as they were previously and wrongly logged.
However, the fix was only partially complete, because on
disconnect, at THD cleanup, the implicit logging of temporary
tables is conditionally performed. If the binlog_format==ROW and
thd->is_current_stmt_binlog_format_row() is true then DROPs are
not logged. Given that the user can switch from STMT to ROW, this
is wrong because the server cannot tell, just by relying on the
ROW binlog format, that the tables have been dropped before. This
is effectively similar to the MIXED scenario when a switch from
STMT to ROW is triggered.
We fix this by removing this condition from
close_temporary_tables.
mysql-test/extra/binlog_tests/drop_temp_table.test:
Added binlog test case.
mysql-test/suite/binlog/r/binlog_row_drop_tmp_tbl.result:
Result changes because:
- there is a missing drop on three temporary tables
- it now contains results for the test added
mysql-test/suite/binlog/r/binlog_row_mix_innodb_myisam.result:
Result now contains the implicit drop for the temporary table.
mysql-test/suite/binlog/r/binlog_stm_drop_tmp_tbl.result:
Result file changed because it now contains results for added
test case.
mysql-test/suite/rpl/r/rpl_drop_temp.result:
Result file changed because it now contains results for added
test case.
mysql-test/suite/rpl/t/rpl_drop_temp.test:
Added replication test case.
sql/sql_base.cc:
Removed the condition that would make the server to skip
logging implicit drops when ROW binary log format mode was
in use.
Additionally, deployed DBUG_ENTER/RETURN macros.
Bug#47633 - assert in ha_myisammrg::info during OPTIMIZE
The server crashed on an attempt to optimize a MERGE table with
non-existent child table.
mysql_admin_table() relied on the table to be successfully open
if a table object had been allocated.
Changed code to check return value of the open function before
calling a handler:: function on it.
mysql-test/r/merge.result:
Backport of revid:ingo.struewing@sun.com-20091223200354-r2uzbdkj2v6yv111
Bug#47633 - assert in ha_myisammrg::info during OPTIMIZE
Updated result file.
mysql-test/t/merge.test:
Backport of revid:ingo.struewing@sun.com-20091223200354-r2uzbdkj2v6yv111
Bug#47633 - assert in ha_myisammrg::info during OPTIMIZE
Changed tests to respect changed TEMPORARY MERGE locking (unrelated).
Changed tests to respect changed CREATE TABLE ... LIKE (unrelated).
Changed tests to respect that no new tables can be created
under LOCK TABLE (unrelated).
Added test for Bug#47633.
Changed error numbers to symbolic names.
Added test for child locking for ALTER under LOCK TABLE.
Since Bug 36171 is not pushed yet, not the whole patch has been backported.
mysys/my_delete.c:
Backport of revid:ingo.struewing@sun.com-20091223200354-r2uzbdkj2v6yv111
Bug#47633 - assert in ha_myisammrg::info during OPTIMIZE
Fixed error reporting.
Fixed indentation.
mysys/my_mmap.c:
Backport of revid:ingo.struewing@sun.com-20091223200354-r2uzbdkj2v6yv111
Bug#47633 - assert in ha_myisammrg::info during OPTIMIZE
Added DBUG.
sql/item_func.cc:
Backport of revid:ingo.struewing@sun.com-20091223200354-r2uzbdkj2v6yv111
Added Debug Sync point, required by merge_sync.test.
sql/sql_table.cc:
Backport of revid:ingo.struewing@sun.com-20091223200354-r2uzbdkj2v6yv111
Bug#47633 - assert in ha_myisammrg::info during OPTIMIZE
Do not call handler:: functions if the table was not opened
successfully.
Added Debug Sync point, required by merge_sync.test.
storage/myisam/mi_check.c:
Backport of revid:ingo.struewing@sun.com-20091223200354-r2uzbdkj2v6yv111
Bug#47633 - assert in ha_myisammrg::info during OPTIMIZE
Unmap memory before exchanging data files. Needed on Windows.
storage/myisammrg/ha_myisammrg.cc:
Backport of revid:ingo.struewing@sun.com-20091223200354-r2uzbdkj2v6yv111
Added Debug Sync point, required by merge_sync.test.
merge_sync.test will be introduced by a patch for Bug 36171,
which is not pushed yet.
DML flow and SAVEPOINT
The problem was that replication could break if a transaction involving
both transactional and non-transactional tables was rolled back to a
savepoint. It broke if a concurrent connection tried to drop a
transactional table which was locked after the savepoint was set.
This DROP TABLE completed when ROLLBACK TO SAVEPOINT was executed as the
lock on the table was dropped by the transaction. When the slave later
tried to apply the binlog, it would fail as the table would already
have been dropped.
The reason for the problem is that transactions involving both
transactional and non-transactional tables are written fully to the
binlog during ROLLBACK TO SAVEPOINT. At the same time, metadata locks
acquired after a savepoint, were released during ROLLBACK TO SAVEPOINT.
This allowed a second connection to drop a table only used between
SAVEPOINT and ROLLBACK TO SAVEPOINT. Which caused the transaction binlog
to refer to a non-existing table when it was written during ROLLBACK
TO SAVEPOINT.
This patch fixes the problem by not releasing metadata locks when
ROLLBACK TO SAVEPOINT is executed if binlogging is enabled.
Problem: SQL and IO thread were racing for the IO_CACHE. The former to
flush it, the latter to close it. In some cases this would cause the
SQL thread to lock an invalid IO_CACHE mutex (it had been destroyed by
IO thread). This would happen when SQL thread was initializing the
master.info
Solution: We solve this by locking the log and checking if it is
hot. If it is we keep the log while seeking. Otherwise we release it
right away, because a log can get from hot to cold, but not from cold
to hot.
Don't call member functions for a NIL pointer.
mysql-test/r/subselect4.result:
Add test case.
mysql-test/t/subselect4.test:
Add test case.
sql/sql_select.cc:
If the (virtual) member function clone_item() returns NULL,
there is no substitution to be made, and we don't need to set the collation.
The test was invoking Item_cache::clone_item()
use limit efficiently
Bug #36569: UPDATE ... WHERE ... ORDER BY... always does a
filesort even if not required
Also two bugs reported after QA review (before the commit
of bugs above to public trees, no documentation needed):
Bug #53737: Performance regressions after applying patch
for bug 36569
Bug #53742: UPDATEs have no effect after applying patch
for bug 36569
Execution of single-table UPDATE and DELETE statements did not use the
same optimizer as was used in the compilation of SELECT statements.
Instead, it had an optimizer of its own that did not take into account
that you can omit sorting by retrieving rows using an index.
Extra optimization has been added: when applicable, single-table
UPDATE/DELETE statements use an existing index instead of filesort. A
corresponding SELECT query would do the former.
Also handling of the DESC ordering expression has been added when
reverse index scan is applicable.
From now on most single table UPDATE and DELETE statements show the
same disk access patterns as the corresponding SELECT query. We verify
this by comparing the result of SHOW STATUS LIKE 'Sort%
Currently the get_index_for_order function
a) checks quick select index (if any) for compatibility with the
ORDER expression list or
b) chooses the cheapest available compatible index, but only if
the index scan is cheaper than filesort.
Second way is implemented by the new test_if_cheaper_ordering
function (extracted part the test_if_skip_sort_order()).
mysql-test/r/log_state.result:
Updated result for optimized query, bug #36569.
mysql-test/r/single_delete_update.result:
Test case for bug #30584, bug #36569 and bug #53742.
mysql-test/r/update.result:
Updated result for optimized query, bug #30584.
Note:
"Handler_read_last 1" omitted, see bug 52312:
lost Handler_read_last status variable.
mysql-test/t/single_delete_update.test:
Test case for bug #30584, bug #36569 and bug #53742.
sql/opt_range.cc:
Bug #30584, bug #36569: UPDATE/DELETE ... WHERE ... ORDER BY...
always does a filesort even if not required
* get_index_for_order() has been rewritten entirely and moved
to sql_select.cc
New QUICK_RANGE_SELECT::make_reverse method has been added.
sql/opt_range.h:
Bug #30584, bug #36569: UPDATE/DELETE ... WHERE ... ORDER BY...
always does a filesort even if not required
* get_index_for_order() has been rewritten entirely and moved
to sql_select.cc
New functions:
* QUICK_SELECT_I::make_reverse()
* SQL_SELECT::set_quick()
sql/records.cc:
Bug #30584, bug #36569: UPDATE/DELETE ... WHERE ... ORDER BY...
always does a filesort even if not required
* init_read_record_idx() has been modified to allow reverse index scan
New functions:
* rr_index_last()
* rr_index_desc()
sql/records.h:
Bug #30584, bug #36569: UPDATE/DELETE ... WHERE ... ORDER BY...
always does a filesort even if not required
init_read_record_idx() has been modified to allow reverse index scan
sql/sql_delete.cc:
Bug #30584, bug #36569: UPDATE/DELETE ... WHERE ... ORDER BY...
always does a filesort even if not required
mysql_delete: an optimization has been added to skip
unnecessary sorting with ORDER BY clause where select
result ordering is acceptable.
sql/sql_select.cc:
Bug #30584, bug #36569, bug #53737, bug #53742:
UPDATE/DELETE ... WHERE ... ORDER BY... always does a filesort
even if not required
The const_expression_in_where function has been modified
to accept both Item and Field pointers.
New functions:
* get_index_for_order()
* test_if_cheaper_ordering() has been extracted from
test_if_skip_sort_order() to share with get_index_for_order()
* simple_remove_const()
sql/sql_select.h:
Bug #30584, bug #36569: UPDATE/DELETE ... WHERE ... ORDER BY...
always does a filesort even if not required
New functions:
* test_if_cheaper_ordering()
* simple_remove_const()
* get_index_for_order()
sql/sql_update.cc:
Bug #30584, bug #36569: UPDATE/DELETE ... WHERE ... ORDER BY...
always does a filesort even if not required
mysql_update: an optimization has been added to skip
unnecessary sorting with ORDER BY clause where a select
result ordering is acceptable.
sql/table.cc:
Bug #30584, bug #36569: UPDATE/DELETE ... WHERE ... ORDER BY...
always does a filesort even if not required
New functions:
* TABLE::update_const_key_parts()
* is_simple_order()
sql/table.h:
Bug #30584, bug #36569: UPDATE/DELETE ... WHERE ... ORDER BY...
always does a filesort even if not required
New functions:
* TABLE::update_const_key_parts()
* is_simple_order()
The default storage engine is changed from MyISAM to
InnoDB, in all builds except for the embedded server.
In addition, the following system variables are
changed:
* innodb_file_per_table is enabled
* innodb_strict_mode is enabled
* innodb_file_format_name_update is changed
to 'Barracuda'
The test suite is changed so that tests that do not
explicitly include the have_innodb.inc are run with
--default-storage-engine=MyISAM. This is to ease the
transition, so that most regression tests are run
with the same engine as before.
Some tests are disabled for the embedded server
regression test, as the output of certain statements
will be different that for the regular server
(i.e SELECT @@default_storage_engine). This is to
ease transition.
mysql-test/mysql-test-run.pl:
The regression test suite now adds a
--default-storage-engine=MyISAM for all non-innodb
tests. This behaviour can be controlled by the
default-myisam switch in mysql-test-run
mysql-test/t/bootstrap-master.opt:
The bootstrap test can only be run without InnoDB
as it starts several mysqld instances on the same
datadir. This is possible with MyISAM, but not
with InnoDB.
storage/innobase/CMakeLists.txt:
Build InnoDB per default
storage/innobase/handler/ha_innodb.cc:
Change default values for system variables
Enable file_per_table
Enable strict_mode
Upgrade default file format to Barracuda
On [Open]Solaris/x86 the FPU was not switched to 64-bit double
precision mode when the server binary was built with Sun
Studio. That caused GIS test failures due to differences in
expected and actual results.
an atomic counter"
Split the large LOCK_open section in open_table().
Do not call open_table_from_share() under LOCK_open.
Remove thd->version.
This fixes
Bug#50589 "Server hang on a query evaluated using a temporary
table"
Bug#51557 "LOCK_open and kernel_mutex are not happy together"
Bug#49463 "LOCK_table and innodb are not nice when handler
instances are created".
This patch has effect on storage engines that rely on
ha_open() PSEA method being called under LOCK_open.
In particular:
1) NDB is broken and left unfixed. NDB relies on LOCK_open
being kept as part of ha_open(), since it uses auto-discovery.
While previously the NDB open code was race-prone, now
it simply fails on asserts.
2) HEAP engine had a race in ha_heap::open() when
a share for the same table could be added twice
to the list of shares, or a dangling reference to a share
stored in HEAP handler. This patch aims to address this
problem by 'pinning' the newly created share in the
internal HEAP engine share list until at least one
handler instance is created using that share.
include/heap.h:
Add members to HP_CREATE_INFO.
Declare heap_release_share().
sql/lock.cc:
Remove thd->version, use thd->open_tables->s->version instead.
sql/repl_failsafe.cc:
Remove thd->version.
sql/sql_base.cc:
- close_thread_table(): move handler cleanup code outside the critical section protected by LOCK_open.
- remove thd->version
- split the large critical section in open_table() that
opens a new table from share and is protected by LOCK_open
into 2 critical sections, thus reducing the critical path.
- make check_if_table_exists() acquire LOCK_open internally.
- use thd->open_tables->s->version instead of thd->refresh_version to make sure that all tables in
thd->open_tables are in the same refresh series.
sql/sql_base.h:
Add declaration for check_if_table_exists().
sql/sql_class.cc:
Remove init_open_tables_state(), it's now equal to
reset_open_tables_state().
sql/sql_class.h:
Remove thd->version, THD::init_open_tables_state().
sql/sql_plugin.cc:
Use table->m_needs_reopen to mark the table as stale
rather than manipulate with thd->version, which is no more.
sql/sql_udf.cc:
Use table->m_needs_reopen to mark the table as stale
rather than manipulate with thd->version, which is no more.
sql/table.h:
Remove an unused variable.
sql/tztime.cc:
Use table->m_needs_reopen to mark the table as stale
rather than manipulate with thd->version, which is no more.
storage/heap/CMakeLists.txt:
Add heap tests to cmake build files.
storage/heap/ha_heap.cc:
Fix a race when ha_heap::ha_open() could insert two
HP_SHARE objects into the internal share list or store
a dangling reference to a share in ha_heap instance,
or wrongly set implicit_emptied.
storage/heap/hp_create.c:
Optionally pin a newly created share in the list of shares
by increasing its open_count. This is necessary to
make sure that a newly created share doesn't disappear while
a HP_INFO object is being created to reference it.
storage/heap/hp_open.c:
When adding a new HP_INFO object to the list of objects
in the heap share, make sure the open_count is not increased
twice.
storage/heap/hp_test1.c:
Adjust the test to new function signatures.
storage/heap/hp_test2.c:
Adjust the test to new function signatures.
Item*) at opt_sum.cc:305
Queries applying MIN/MAX functions to indexed columns are
optimized to read directly from the index if all key parts
of the index preceding the aggregated key part are bound to
constants by the WHERE clause. A prefix length is also
produced, equal to the total length of the bound key
parts. If the aggregated column itself is bound to a
constant, however, it is also included in the prefix.
Such full search keys are read as closed intervals for
reasons beyond the scope of this bug. However, the procedure
missed one case where a key part meant for use as range
endpoint was being overwritten with a NULL value destined
for equality checking. In this case the key part was
overwritten but the range flag remained, causing open
interval reading to be performed.
Bug was fixed by adding more stringent checking to the
search key building procedure (matching_cond) and never
allow overwrites of range predicates with non-range
predicates.
An assertion was added to make sure open intervals are never
used with full search keys.
strict aliasing violations.
One somewhat major source of strict-aliasing violations and
related warnings is the SQL_LIST structure. For example,
consider its member function `link_in_list` which takes
a pointer to pointer of type T (any type) as a pointer to
pointer to unsigned char. Dereferencing this pointer, which
is done to reset the next field, violates strict-aliasing
rules and might cause problems for surrounding code that
uses the next field of the object being added to the list.
The solution is to use templates to parametrize the SQL_LIST
structure in order to deference the pointers with compatible
types. As a side bonus, it becomes possible to remove quite
a few casts related to acessing data members of SQL_LIST.
sql/handler.h:
Use the appropriate template type argument.
sql/item.cc:
Remove now-unnecessary cast.
sql/item_subselect.cc:
Remove now-unnecessary casts.
sql/item_sum.cc:
Use the appropriate template type argument.
Remove now-unnecessary cast.
sql/mysql_priv.h:
Move SQL_LIST structure to sql_list.h
Use the appropriate template type argument.
sql/sp.cc:
Remove now-unnecessary casts.
sql/sql_delete.cc:
Use the appropriate template type argument.
Remove now-unnecessary casts.
sql/sql_derived.cc:
Remove now-unnecessary casts.
sql/sql_lex.cc:
Remove now-unnecessary casts.
sql/sql_lex.h:
SQL_LIST now takes a template type argument which must
match the type of the elements of the list. Use forward
declaration when the type is not available, it is used
in pointers anyway.
sql/sql_list.h:
Rename SQL_LIST to SQL_I_List. The template parameter is
the type of object that is stored in the list.
sql/sql_olap.cc:
Remove now-unnecessary casts.
sql/sql_parse.cc:
Remove now-unnecessary casts.
sql/sql_prepare.cc:
Remove now-unnecessary casts.
sql/sql_select.cc:
Remove now-unnecessary casts.
sql/sql_show.cc:
Remove now-unnecessary casts.
sql/sql_table.cc:
Remove now-unnecessary casts.
sql/sql_trigger.cc:
Remove now-unnecessary casts.
sql/sql_union.cc:
Remove now-unnecessary casts.
sql/sql_update.cc:
Remove now-unnecessary casts.
sql/sql_view.cc:
Remove now-unnecessary casts.
sql/sql_yacc.yy:
Remove now-unnecessary casts.
storage/myisammrg/ha_myisammrg.cc:
Remove now-unnecessary casts.
strict aliasing violations.
Essentially, the problem is that large parts of the server were
developed in simpler times (last decades, pre C99 standard) when
strict aliasing and compilers supporting such optimizations were
rare to non-existent. Thus, when compiling the server with a modern
compiler that uses strict aliasing rules to perform optimizations,
there are several places in the code that might trigger undefined
behavior.
As evinced by some recent bugs, GCC does a somewhat good of job
misoptimizing such code, but on the other hand also gives warnings
about suspicious code. One problem is that the warnings aren't
always accurate, yet we can't afford to just shut them off as we
might miss real cases. False-positive cases are aggravated mostly
by casts that are likely to trigger undefined behavior.
The solution is to start a cleanup process focused on fixing and
reducing the amount of strict-aliasing related warnings produced
by GCC and others compilers. A good deal of noise reduction can
be achieved by just removing useless casts that are product of
historical cruft and are likely to trigger undefined behavior if
dereferenced.
client/mysql.cc:
Remove now-unnecessary casts.
Break up large strings.
client/mysql_upgrade.c:
Remove now-unnecessary casts.
client/mysqladmin.cc:
Remove now-unnecessary casts.
Break up large strings.
client/mysqlbinlog.cc:
Remove now-unnecessary casts.
client/mysqlcheck.c:
Remove now-unnecessary casts.
client/mysqldump.c:
Remove now-unnecessary casts.
client/mysqlimport.c:
Remove now-unnecessary casts.
client/mysqlshow.c:
Remove now-unnecessary casts.
client/mysqlslap.c:
Remove now-unnecessary casts.
client/mysqltest.cc:
Remove now-unnecessary casts.
extra/comp_err.c:
Remove now-unnecessary casts.
extra/my_print_defaults.c:
Remove now-unnecessary casts.
Break up large strings.
extra/mysql_waitpid.c:
Remove now-unnecessary casts.
extra/perror.c:
Remove now-unnecessary casts.
extra/resolve_stack_dump.c:
Remove now-unnecessary casts.
extra/resolveip.c:
Remove now-unnecessary casts.
include/my_getopt.h:
Use a void pointer type as the opaque type to avoid problems with type
incompatibility -- GCC issues warnings when the type name is not type
compatible with a operand. As a side bonus, a explicit cast won't be
necessary anymore.
include/sslopt-longopts.h:
Remove now-unnecessary casts.
Break up large strings.
mysys/my_getopt.c:
Update opaque type and introduce a type definition for the
argument to my_getopt_register_get_addr.
server-tools/instance-manager/options.cc:
Remove now-unnecessary casts.
sql/mysqld.cc:
Remove now-unnecessary casts.
Break up large strings.
Update mysql_getopt_value prototype (the old prototype
was different from the definition anyway).
sql/sql_plugin.cc:
The type of a pointer to a function must be compatible with the
pointed-to function type, otherwise the behavior is undefined.
sql/table.cc:
The variable buf pointer to pointer to pointer to constant char
could improperly alias a incompatible type in call to fix_type_
pointers. Since this was actually dead code, it is simply removed.
sql/unireg.cc:
Remove call to get_form_pos. The code creates a new FRM file which
is always truncated and writes the form position as 0. Hence, no
need to retrieve it, we now for sure it is 0.
storage/archive/archive_reader.c:
Remove now-unnecessary casts.
storage/myisam/ft_nlq_search.c:
Read weight directly from the buffer.
storage/myisam/fulltext.h:
Add explanation about the type duality of a key buffer.
Add accessor macro to retrieve a FT float value.
storage/myisam/mi_test1.c:
Remove now-unnecessary casts.
storage/myisam/myisam_ftdump.c:
Read weight directly from the buffer.
storage/myisam/myisamchk.c:
Remove now-unnecessary casts.
storage/myisam/myisamlog.c:
A pointer to char was used to alias a pointer to pointer to
unsigned char, thus violating strict aliasing rules.
storage/myisam/myisampack.c:
Remove now-unnecessary casts.
strings/decimal.c:
Remove aliasing violation, printing the value is enough for
debugging purposes.
tests/mysql_client_test.c:
Remove now-unnecessary casts.
