Problems:
- dot character was always printed as decimal point
instead of localized decimal point for short
numbers without thousands
- Item_func_format::val_str always returned values in ASCII
format,
regargless of @@character_set_connection, which in case of utf32
led to crash in debug build, or to incorrect values in release build.
Fix:
- Adding a piece of code to replace dot character to
localized decimal point in short numbers.
- Changing parent class for Item_func_format to
Item_str_ascii_func, because its val_str() implementation is heavily ASCII oriented.
on CREATE TABLE .. SELECT I_S.PART
This assert was triggered if an InnoDB table was created using
CREATE TABLE ... AS SELECT where the query used an I_S table, and
a view existed in the database. It would also be triggered for
any statement changing an InnoDB table (e.g. INSERT, UPDATE, DELETE)
which had a subquery referencing an I_S table.
The assert was triggered if open_normal_and_derived_tables() failed
and a statement transaction had been started. This will usually not
happen as tables are opened before a statement transaction is started.
However, e.g. CREATE TABLE ... AS SELECT starts a transaction in order
to insert tuples into the new table. And if the subquery references
an I_S table, all current tables and views can be opened in order to
fill the I_S table on the fly. If a view is discovered, open will fail
as it is instructed to open tables only (OPEN_TABLE_ONLY). This would
cause the assert to be triggered.
The assert was added in the patch for Bug#52044 and was therefore
not in any released versions of the server.
This patch fixes the problem by adjusting the assert to take into
consideration the possibility of tables being opened as part of
an I_S query. This is similar to what is already done for
close_tables_for_reopen().
Test case added to information_schema_inno.test.
temp table
This patch introduces two key changes in the replication's behavior.
Firstly, it reverts part of BUG#51894 which puts any update to temporary tables
into the trx-cache. Now, updates to temporary tables are handled according to
the type of their engines as a regular table.
Secondly, an unsafe mixed statement, (i.e. a statement that access transactional
table as well non-transactional or temporary table, and writes to any of them),
are written into the trx-cache in order to minimize errors in the execution when
the statement logging format is in use.
Such changes has a direct impact on which statements are classified as unsafe
statements and thus part of BUG#53259 is reverted.
Problem: a few functions did not calculate their max_length correctly.
This is an after-fix for WL#2649 Number-to-string conversions".
Fix: changing the buggy functions to calculate max_length
using fix_char_length() introduced in WL#2649,
instead of setting max_length directly
mysql-test/include/ctype_numconv.inc
Adding new tests
mysql-test/r/ctype_binary.result
Adding new tests
mysql-test/r/ctype_cp1251.result
Adding new tests
mysql-test/r/ctype_latin1.result
Adding new tests
mysql-test/r/ctype_ucs.result
Adding new tests
mysql-test/r/ctype_utf8.result
Adding new tests
mysql-test/t/ctype_utf8.test
Including ctype_numconv
sql/item.h
- Introducing new method fix_char_length_ulonglong(),
for the cases when length is potentially greater
than UINT_MAX32. This method removes a few
instances of duplicate code, e.g. in item_strfunc.cc.
- Setting collation in Item_copy properly. This change
fixes wrong metadata on client side in some cases, when
"binary" instead of the real character set was reported.
sql/item_cmpfunc.cc
- Using fix_char_length() and max_char_length() methods,
instead of direct access to max_length, to calculate
item length properly.
- Moving count_only_length() in COALESCE after
agg_arg_charsets_for_string_result(). The old
order was incorrect and led to wrong length
calucation in case of multi-byte character sets.
sql/item_func.cc
Fixing that count_only_length() didn't work
properly for multi-byte character sets.
Using fix_char_length() and max_char_length()
instead of direct access to max_length.
sql/item_strfunc.cc
- Using fix_char_length(), fix_char_length_ulonglong(),
max_char_length() instead of direct access to max_length.
- Removing wierd condition: "if (collation.collation->mbmaxlen > 0)",
which is never FALSE.
Problem: Item_func_hex::val_str() returned data in ASCII format,
which did not match collation.collation pointing to my_charset_utf32_general_ci.
Fix: changing parent class of Item_func_hex to Item_str_ascii_func,
as val_str() implementation is heavily ASCII-oriented.
mysql-test/r/ctype_utf32.result
mysql-test/t/ctype_utf32.test
Adding test case
sql/item_strfunc.cc
sql/item_strfunc.h
- Changing parent class to Item_str_ascii_func
- Clean-up in Item_func_hex::fix_length_and_dec()
Using fix_char_length() instead of setting max_length directly.
'CREATE TABLE IF NOT EXISTS ... SELECT' behaviour
BUG#47132, BUG#47442, BUG49494, BUG#23992 and BUG#48814 will disappear
automatically after the this patch.
BUG#55617 is fixed by this patch too.
This is the 5.5 part.
It implements:
- 'CREATE TABLE IF NOT EXISTS ... SELECT' statement will not insert
anything and binlog anything if the table already exists.
It only generate a warning that table already exists.
- A couple of test cases for the behavior changing.
Followup to vasil.dimov@oracle.com-20100817063430-inglmzgdtj95t29d
which didn't fully fix the test because the order of the returned
rows was different in embedded and non-embedded version. So the only
way to fix this is to add an ORDER BY clause.
locks on the table
Fixing the partitioning specifics after TRUNCATE TABLE in
bug-42643 was fixed.
Reorganize of code to decrease the size of the giant switch
in mysql_execute_command, and to prepare for future parser
reengineering. Moved code into Sql_statement objects.
Updated patch according to davi's review comments.
libmysqld/CMakeLists.txt:
Added new files.
libmysqld/Makefile.am:
Added new files.
mysql-test/r/not_partition.result:
now returning error on partitioning commands
if partitioning is not enabled.
mysql-test/r/partition_disabled.result:
There is no partition handlerton, so it cannot
find the specified engine in the .frm file.
mysql-test/r/partition_truncate.result:
Updated test results.
mysql-test/suite/parts/inc/partition_mgm.inc:
Added check that TRUNCATE PARTITION does not delete on failure.
mysql-test/suite/parts/r/partition_debug_sync_innodb.result:
updated results.
mysql-test/suite/parts/r/partition_mgm_lc0_archive.result:
updated results.
mysql-test/suite/parts/r/partition_mgm_lc1_archive.result:
updated results.
mysql-test/suite/parts/r/partition_mgm_lc2_archive.result:
updated results.
mysql-test/suite/parts/t/partition_debug_sync_innodb.test:
Test case for this bug.
mysql-test/t/not_partition.test:
Added check for TRUNCATE PARTITION without partitioning.
mysql-test/t/partition_truncate.test:
Added test of TRUNCATE PARTITION on non partitioned table.
sql/CMakeLists.txt:
Added new files.
sql/Makefile.am:
Added new files.
sql/datadict.cc:
Moved out the storage engine check into an own
function, including assert for lock.
sql/datadict.h:
added dd_frm_storage_engine.
sql/sql_alter_table.cc:
moved the code for SQLCOM_ALTER_TABLE in mysql_execute_command
into its own file, and using the Sql_statement object to
prepare for future parser reengineering.
sql/sql_alter_table.h:
Created Sql_statement object for ALTER TABLE.
sql/sql_lex.cc:
resetting m_stmt.
sql/sql_lex.h:
Temporary hack for forward declaration of enum_alter_table_change_level.
sql/sql_parse.cc:
Moved out ALTER/ANALYZE/CHECK/OPTIMIZE/REPAIR TABLE
from the giant switch into their own Sql_statement
objects.
sql/sql_parse.h:
Exporting check_merge_table_access.
sql/sql_partition_admin.cc:
created Sql_statement for
ALTER TABLE t ANALYZE/CHECK/OPTIMIZE/REPAIR/TRUNCATE
PARTITION. To be able to reuse the TABLE equivalents.
sql/sql_partition_admin.h:
Added Sql_statement of partition admin statements.
sql/sql_table.cc:
Moved table maintenance code into sql_table_maintenance.cc
sql/sql_table.h:
Moved table maintenance code into sql_table_maintenance.h
exporting functions used by sql_table_maintenance.
sql/sql_table_maintenance.cc:
Moved table maintenance code from sql_table.cc
sql/sql_table_maintenance.h:
Sql_statement objects for ANALYZE/CHECK/OPTIMIZE/REPAIR TABLE.
Also declaring the keycache functions.
sql/sql_truncate.cc:
Moved code from SQLCOM_TRUNCATE in mysql_execute_command into
Truncate_statement::execute.
Added check for partitioned table on TRUNCATE PARTITION.
Moved locking fix for partitioned table into
Alter_table_truncate_partition::execute.
sql/sql_truncate.h:
Truncate_statement declaration (sub class of Sql_statement).
sql/sql_yacc.yy:
Using the new Sql_statment objects.
The bug was fixed by the patch for Bug 52044.
Add a test case.
mysql-test/r/flush.result:
Update results (Bug#52117)
mysql-test/t/flush.test:
Add a test case for Bug#52117 "Pending FLUSH TALBES <list> aborts
transactions unnecessarily"
The problem was that SHOW CREATE EVENT released all metadata locks
held by the current transaction. This made any exisiting savepoints
invalid, triggering the assert when ROLLBACK TO SAVEPOINT later
was executed.
This patch fixes the problem by making sure SHOW CREATE EVENT only
releases metadata locks acquired by the statement itself.
Test case added to event_trans.test.
corruption on ADD PARTITION and LOCK TABLE
Bug#53770: Server crash at handler.cc:2076 on
LOAD DATA after timed out COALESCE PARTITION
5.5 fix for:
Bug#51042: REORGANIZE PARTITION can leave table in an
inconsistent state in case of crash
Needs to be back-ported to 5.1
5.5 fix for:
Bug#50418: DROP PARTITION does not interact with
transactions
Main problem was non-persistent operations done
before meta-data lock was taken (53770+53676).
And 53676 needed to keep the table/partitions opened and locked
while copying the data to the new partitions.
Also added thorough tests to spot some additional bugs
in the ddl_log code, which could result in bad state
between the .frm and partitions.
Collapsed patch, includes all fixes required from the reviewers.
mysql-test/r/partition_innodb.result:
updated result with new test
mysql-test/suite/parts/inc/partition_crash.inc:
crash test include file
mysql-test/suite/parts/inc/partition_crash_add.inc:
test all states in fast_alter_partition_table
ADD PARTITION branch
mysql-test/suite/parts/inc/partition_crash_change.inc:
test all states in fast_alter_partition_table
CHANGE PARTITION branch
mysql-test/suite/parts/inc/partition_crash_drop.inc:
test all states in fast_alter_partition_table
DROP PARTITION branch
mysql-test/suite/parts/inc/partition_fail.inc:
recovery test including injecting errors
mysql-test/suite/parts/inc/partition_fail_add.inc:
test all states in fast_alter_partition_table
ADD PARTITION branch
mysql-test/suite/parts/inc/partition_fail_change.inc:
test all states in fast_alter_partition_table
CHANGE PARTITION branch
mysql-test/suite/parts/inc/partition_fail_drop.inc:
test all states in fast_alter_partition_table
DROP PARTITION branch
mysql-test/suite/parts/inc/partition_mgm_crash.inc:
include file that runs all crash and failure injection tests.
mysql-test/suite/parts/r/partition_debug_innodb.result:
new test result file
mysql-test/suite/parts/r/partition_debug_myisam.result:
new test result file
mysql-test/suite/parts/r/partition_special_innodb.result:
updated result
mysql-test/suite/parts/r/partition_special_myisam.result:
updated result
mysql-test/suite/parts/t/partition_debug_innodb-master.opt:
opt file for using with crashing tests of partitioned innodb
mysql-test/suite/parts/t/partition_debug_innodb.test:
partitioned innodb test that require debug builds
mysql-test/suite/parts/t/partition_debug_myisam-master.opt:
opt file for using with crashing tests of partitioned myisam
mysql-test/suite/parts/t/partition_debug_myisam.test:
partitioned myisam test that require debug builds
mysql-test/suite/parts/t/partition_special_innodb-master.opt:
added innodb-file-per-table to easier verify partition status on disk
mysql-test/suite/parts/t/partition_special_innodb.test:
added test case
mysql-test/suite/parts/t/partition_special_myisam.test:
added test case
mysql-test/t/partition_innodb.test:
added test case
sql/sql_base.cc:
Moved alter_close_tables to sql_partition.cc
sql/sql_base.h:
removed some non existing and duplicated functions.
sql/sql_partition.cc:
fast_alter_partition_table:
Spletted abort_and_upgrad_lock_and_close_table
to its parts (wait_while_table_is_used and
alter_close_tables) and always have
wait_while_table_is_used before any persistent
operations (including logs, which will be executed
on failure) and alter_close_tables after
create/read/write operations and before
drop operations.
moved alter_close_tables here from sql_base.cc
Added error injections for better test coverage.
write_log_final_change_partition:
fixed a log_entry linking bug (delete_frm was not
linked to change/drop partition)
and drop partition must be executed before
change partition (change partition can rename a
partition to an old name, like REORG p1 INTO (p1,p2).
write_log_add_change_partition:
need to use drop_frm first, and relinking that entry
and reusing its execute entry.
sql/sql_table.cc:
added initialization of next_active_log_entry.
sql/table.h:
removed a duplicate declaration.
it couldn't parse the --ssl option.
client/mysql_upgrade.c:
mysql_upgrade parses its options and passes some of them to the underlying
tools (mysqlcheck etc). To do this passdown, it reconstructs a
command-line-suitable text from the my_option object (which
contains the option's name and option's value). For options
which expect no parameter, it just had to use the option's name;
for other options, it had to concatenate the option's name,
a "=" symbol, and the option's value; it had code to handle
this latter case, but only for GET_STR options (options taking a
string as value). But since the work on WL 4738, the --ssl
option, a GET_BOOL, which used to have no parameter (NO_ARG), can
now have one (OPT_ARG), so with --ssl we came to the "default"
label, error. Fixed by constructing the command-line-suitable
representation for GET_BOOL too. For --ssl it will produce
--ssl=1 ; for --ssl=0, it will produce --ssl=0.
mysql-test/include/mysql_upgrade_preparation.inc:
handles requirements of tests which use mysql_upgrade
mysql-test/r/mysql_upgrade_ssl.result:
result; without the code fix we would get "internal error".
mysql-test/t/mysql_upgrade.test:
This test has requirements before running; moved them
to an include file in order to share with mysql_upgrade_ssl.
mysql-test/t/mysql_upgrade_ssl.test:
test for bug. Couldn't go into mysql_upgrade.test as this new test requires
SSL support. --force is needed, in case mysql_upgrade.test run before
(in which case mysql_upgrade_ssl would say that upgrade has already been
done); --force forces the upgrade in all cases.
feature
The test for bug no 50939 was put in range.test which isn't such a good idea
since it requires partitioning. Fixed by moving the test case to
partitioning_range.test.
with open HANDLER
This patch changes the code for table renames to not drop metadata
locks. Since table renames are done as a part of ALTER DATABASE ...
UPGRADE, dropping metadata locks in the middle of execution can
result in wrong binlog order since it means that no locks are held
when the binlog is written to.
The RENAME TABLE statement is unafffected since it auto commits and
therefore already drops metadata locks at the end of execution.
This patch also reverts the regression test for Bug#48940 back to
its original version. The test was temporarily changed due to the
issue mentioned above.
INSERT IGNORE ... SELECT ... UNION SELECT ...
This assert was triggered by INSERT IGNORE ... SELECT. The assert checks that a
statement either sends OK or an error to the client. If the bug was triggered
on release builds, it caused OK to be sent to the client instead of the correct
error message (in this case ER_FIELD_SPECIFIED_TWICE).
The reason the assert was triggered, was that lex->no_error was set to TRUE
during JOIN::optimize() because of IGNORE. This causes all errors to be ignored.
However, not all errors can be ignored. Some, such as ER_FIELD_SPECIFIED_TWICE
will cause the INSERT to fail no matter what. But since lex->no_error was set,
the critical errors were ignored, the INSERT failed and neither OK nor the
error message was sent to the client.
This patch fixes the problem by temporarily turning off lex->no_error in
places where errors cannot be ignored during processing of INSERT ... SELECT.
Test case added to insert.test.
FLUSH TABLES <list> WITH READ LOCK are incompatible" to
be pushed as separate patch.
Replaced thread state name "Waiting for table", which was
used by threads waiting for a metadata lock or table flush,
with a set of names which better reflect types of resources
being waited for.
Also replaced "Table lock" thread state name, which was used
by threads waiting on thr_lock.c table level lock, with more
elaborate "Waiting for table level lock", to make it
more consistent with other thread state names.
Updated test cases and their results according to these
changes.
Fixed sys_vars.query_cache_wlock_invalidate_func test to not
to wait for timeout of wait_condition.inc script.
mysql-test/r/query_cache.result:
Added test coverage for query_cache_wlock_invalidate
behavior for implicitly locked tables.
mysql-test/suite/sys_vars/r/query_cache_wlock_invalidate_func.result:
Fixed sys_vars.query_cache_wlock_invalidate_func test to not
to wait for timeout of wait_condition.inc script. Reverted
changes to test which introduced timeout and replaced waiting
condition with a more appropriate one.
Test coverage for query_cache_wlock_invalidate behavior for
implicitly locked tables was added to query_cache.test.
mysql-test/suite/sys_vars/t/query_cache_wlock_invalidate_func.test:
Fixed sys_vars.query_cache_wlock_invalidate_func test to not
to wait for timeout of wait_condition.inc script. Reverted
changes to test which introduced timeout and replaced waiting
condition with a more appropriate one.
Test coverage for query_cache_wlock_invalidate behavior for
implicitly locked tables was added to query_cache.test.
mysql-test/t/query_cache.test:
Added test coverage for query_cache_wlock_invalidate
behavior for implicitly locked tables.
mysys/thr_lock.c:
Replaced "Table lock" thread state name, which was used by
threads waiting on thr_lock.c table level lock, with more
elaborate "Waiting for table level lock", to make it
consistent with thread state names which are used while
waiting for metadata locks and table flush.
sql/mdl.cc:
Replaced thread state name "Waiting for table", which was
used by threads waiting for a metadata lock or table flush,
with a set of names which better reflect types of resources
being waited for.
To implement this:
- Adjusted MDL_wait::timed_wait() to take thread state name
as parameter.
- Introduced method of MDL_key class which allows to get
thread state name to be used while waiting for resource
corresponding to the key and changed code to use it.
Added array translating namespaces to thread state names
as part of this change.
sql/mdl.h:
To implement this:
- Adjusted MDL_wait::timed_wait() to take thread state name
as parameter.
- Introduced method of MDL_key class which allows to get
thread state name to be used while waiting for resource
corresponding to the key and changed code to use it.
Added array translating namespaces to thread state names
as part of this change.
sql/sql_base.cc:
Replaced thread state name "Waiting for table", which was
used by threads waiting for table flush, with a more elaborate
"Waiting for table flush".
file .\item_subselect.cc, line 836
IN quantified predicates are never executed directly. They are rather wrapped
inside nodes called IN Optimizers (Item_in_optimizer) which take care of the
execution. However, this is not done during query preparation. Unfortunately
the LIKE predicate pre-evaluates constant right-hand side arguments even
during name resolution. Likely this is meant as an optimization.
Fixed by not pre-evaluating LIKE arguments in view prepare mode.
if() treated any non-numeric string as false
Fixed to treat those as true instead
Added some test cases
Fixed missing $ in variable name in include/mix2.inc
A typo in the Item_cache_datetime::val_str caused an assertion to fail on the
maximum time value.
mysql-test/r/func_group.result:
A test case for the bug#55648.
mysql-test/t/func_group.test:
A test case for the bug#55648.
sql/item.cc:
Bug#55648: Server crash on MIX/MAX on maximum time value
Corrected assertion.
******
This patch fixes the following bugs:
- Bug#5889: Exit handler for a warning doesn't hide the warning in
trigger
- Bug#9857: Stored procedures: handler for sqlwarning ignored
- Bug#23032: Handlers declared in a SP do not handle warnings generated
in sub-SP
- Bug#36185: Incorrect precedence for warning and exception handlers
The problem was in the way warnings/errors during stored routine execution
were handled. Prior to this patch the logic was as follows:
- when a warning/an error happens: if we're executing a stored routine,
and there is a handler for that warning/error, remember the handler,
ignore the warning/error and continue execution.
- after a stored routine instruction is executed: check for a remembered
handler and activate one (if any).
This logic caused several problems:
- if one instruction generates several warnings (errors) it's impossible
to choose the right handler -- a handler for the first generated
condition was chosen and remembered for activation.
- mess with handling conditions in scopes different from the current one.
- not putting generated warnings/errors into Warning Info (Diagnostic
Area) is against The Standard.
The patch changes the logic as follows:
- Diagnostic Area is cleared on the beginning of each statement that
either is able to generate warnings, or is able to work with tables.
- at the end of a stored routine instruction, Diagnostic Area is left
intact.
- Diagnostic Area is checked after each stored routine instruction. If
an instruction generates several condition, it's now possible to take a
look at all of them and determine an appropriate handler.
mysql-test/r/signal.result:
Update result file:
1. handled conditions are not cleared any more;
2. reflect changes in signal.test
mysql-test/r/signal_demo3.result:
Update result file: handled conditions are not cleared any more.
Due to playing with max_error_count, resulting warning lists
have changed.
mysql-test/r/sp-big.result:
Update result file: handled conditions are not cleared any more.
mysql-test/r/sp-bugs.result:
Update result file: handled conditions are not cleared any more.
mysql-test/r/sp-code.result:
Update result file:
1. handled conditions are not cleared any more.
2. add result for a new test case in sp-code.test.
mysql-test/r/sp-error.result:
Update result file:
1. handled conditions are not cleared any more.
2. add result for a new test case in sp-error.test.
mysql-test/r/sp.result:
Update result file: handled conditions are not cleared any more.
mysql-test/r/sp_trans.result:
Update result file: handled conditions are not cleared any more.
mysql-test/r/strict.result:
Update result file: handled conditions are not cleared any more.
mysql-test/r/view.result:
Update result file: handled conditions are not cleared any more.
mysql-test/suite/funcs_1/r/innodb_storedproc_02.result:
Update result file: handled conditions are not cleared any more.
mysql-test/suite/funcs_1/r/memory_storedproc_02.result:
Update result file: handled conditions are not cleared any more.
mysql-test/suite/funcs_1/r/myisam_storedproc_02.result:
Update result file: handled conditions are not cleared any more.
mysql-test/suite/funcs_1/r/storedproc.result:
Update result file: handled conditions are not cleared any more.
mysql-test/suite/rpl/r/rpl_row_sp005.result:
Update result file: handled conditions are not cleared any more.
mysql-test/suite/rpl/r/rpl_row_sp006_InnoDB.result:
Update result file: handled conditions are not cleared any more.
mysql-test/suite/rpl/r/rpl_row_trig003.result:
Update result file: handled conditions are not cleared any more.
mysql-test/t/signal.test:
Make a test case more readable in the result file.
mysql-test/t/sp-code.test:
Add a test case for Bug#23032 checking that
No Data takes precedence on Warning.
mysql-test/t/sp-error.test:
Adding test cases for:
- Bug#23032
- Bug#36185
- Bug#5889
- Bug#9857
mysql-test/t/sp.test:
Fixing test case to reflect behavioral changes made by the patch.
sql/sp_head.cc:
Reset the per-statement warning count before executing
a stored procedure instruction.
Move to a separate function code which checks the
completion status of the executed statement and searches
for a handler.
Remove redundant code now that search for a handler is
done after execution, errors are always pushed.
sql/sp_pcontext.h:
Remove unused code.
sql/sp_rcontext.cc:
- Polish sp_rcontext::find_handler(): use sp_rcontext::m_hfound instead
of an extra local variable;
- Remove sp_rcontext::handle_condition();
- Introduce sp_rcontext::activate_handler(), which prepares
previously found handler for execution.
- Move sp_rcontext::enter_handler() code into activate_handler(),
because enter_handler() is used only from there;
- Cleanups;
- Introduce DBUG_EXECUTE_IF() for a test case in sp-code.test
sql/sp_rcontext.h:
- Remove unused code
- Cleanups
sql/sql_class.cc:
Merge THD::raise_condition_no_handler() into THD::raise_condition().
After the patch raise_condition_no_handler() was called
in raise_condition() only.
sql/sql_class.h:
Remove raise_condition_no_handler().
sql/sql_error.cc:
Remove Warning_info::reserve_space() -- handled conditions are not
cleared any more, so there is no need for RESIGNAL to re-push them.
sql/sql_error.h:
Remove Warning_info::reserve_space().
sql/sql_signal.cc:
Handled conditions are not cleared any more,
so there is no need for RESIGNAL to re-push them.
In order to be able to check if the set of the grouping fields in a
GROUP BY has changed (and thus to start a new group) the optimizer
caches the current values of these fields in a set of Cached_item
derived objects.
The Cached_item_str, used for caching varchar and TEXT columns,
is limited in length by the max_sort_length variable.
A String buffer to store the value with an alloced length of either
the max length of the string or the value of max_sort_length
(whichever is smaller) in Cached_item_str's constructor.
Then, at compare time the value of the string to compare to was
truncated to the alloced length of the string buffer inside
Cached_item_str.
This is all fine and valid, but only if you're not assigning
values near or equal to the alloced length of this buffer.
Because when assigning values like this the alloced length is
rounded up and as a result the next set of data will not match the
group buffer, thus leading to wrong results because of the changed
alloced_length.
Fixed by preserving the original maximum length in the
Cached_item_str's constructor and using this instead of the
alloced_length to limit the string to compare to.
Test case added.
