- Fixed problem with oqgraph and 'make dist'
Note that after this merge we have a problem show in join_outer where we examine too many rows in one specific case (related to BUG#57024).
This will be fixed when mwl#128 is merged into 5.3.
Registration of pointer change if we assign it to other pointer which should be identical after statement execution (PS/SP).
mysql-test/r/subselect.result:
Test suite.
mysql-test/t/subselect.test:
Test suite.
sql/sql_class.cc:
The procedure of the pointer registration.
sql/sql_class.h:
The procedure of the pointer registration.
sql/sql_lex.cc:
Registration of pointer change if we assign it to other pointer which should be identical after statement execution (PS/SP).
- Changed to still use bcmp() in certain cases becasue
- Faster for short unaligneed strings than memcmp()
- Bettern when using valgrind
- Changed to use my_sprintf() instead of sprintf() to get higher portability for old systems
- Changed code to use MariaDB version of select->skip_record()
- Removed -%::SCCS/s.% from Makefile.am:s to remove automake warnings
Fix compiler warnings.
mysys/stacktrace.c:
Tag unused parameters.
sql/sql_lex.cc:
Variable becomes unused in non-debug builds. Also, no need to
assert the obvious.
/*![:version:] Query Code */, where [:version:] is a sequence of 5
digits representing the mysql server version(e.g /*!50200 ... */),
is a special comment that the query in it can be executed on those
servers whose versions are larger than the version appearing in the
comment. It leads to a security issue when slave's version is larger
than master's. A malicious user can improve his privileges on slaves.
Because slave SQL thread is running with SUPER privileges, so it can
execute queries that he/she does not have privileges on master.
This bug is fixed with the logic below:
- To replace '!' with ' ' in the magic comments which are not applied on
master. So they become common comments and will not be applied on slave.
- Example:
'INSERT INTO t1 VALUES (1) /*!10000, (2)*/ /*!99999 ,(3)*/
will be binlogged as
'INSERT INTO t1 VALUES (1) /*!10000, (2)*/ /* 99999 ,(3)*/
mysql-test/suite/rpl/t/rpl_conditional_comments.test:
Test the patch for this bug.
sql/mysql_priv.h:
Rename inBuf as rawBuf and remove the const limitation.
sql/sql_lex.cc:
To replace '!' with ' ' in the magic comments which are not applied on
master.
sql/sql_lex.h:
Remove the const limitation on parameter buff, as it can be modified in the function since
this patch.
Add member function yyUnput for Lex_input_stream. It set a character back the query buff.
sql/sql_parse.cc:
Rename inBuf as rawBuf and remove the const limitation.
sql/sql_partition.cc:
Remove the const limitation on parameter part_buff, as it can be modified in the function since
this patch.
sql/sql_partition.h:
Remove the const limitation on parameter part_buff, as it can be modified in the function since
this patch.
sql/table.h:
Remove the const limitation on variable partition_info, as it can be modified since
this patch.
There were two problems that caused wrong results reported with this bug.
1. In some cases stored(persistent) virtual columns were not marked
in the write_set and in the vcol_set bitmaps.
2. If the list of fields in an insert command was empty then the values of
the stored virtual columns were set to default.
To fix the first problem the function st_table::mark_virtual_columns_for_write
was modified. Now the function has a parameter that says whether the virtual
columns are to be marked for insert or for update.
To fix the second problem a special handling of empty insert lists is
added in the function fill_record().
libmysqld/Makefile.am:
The new file added.
mysql-test/r/index_merge_myisam.result:
subquery_cache optimization option added.
mysql-test/r/myisam_mrr.result:
subquery_cache optimization option added.
mysql-test/r/subquery_cache.result:
The subquery cache tests added.
mysql-test/r/subselect3.result:
Subquery cache switched off to avoid changing read statistics.
mysql-test/r/subselect3_jcl6.result:
Subquery cache switched off to avoid changing read statistics.
mysql-test/r/subselect_no_mat.result:
subquery_cache optimization option added.
mysql-test/r/subselect_no_opts.result:
subquery_cache optimization option added.
mysql-test/r/subselect_no_semijoin.result:
subquery_cache optimization option added.
mysql-test/r/subselect_sj.result:
subquery_cache optimization option added.
mysql-test/r/subselect_sj_jcl6.result:
subquery_cache optimization option added.
mysql-test/t/subquery_cache.test:
The subquery cache tests added.
mysql-test/t/subselect3.test:
Subquery cache switched off to avoid changing read statistics.
sql/CMakeLists.txt:
The new file added.
sql/Makefile.am:
The new files added.
sql/item.cc:
Expression cache item (Item_cache_wrapper) added.
Item_ref and Item_field fixed for correct usage of result field and fast resolwing in SP.
sql/item.h:
Expression cache item (Item_cache_wrapper) added.
Item_ref and Item_field fixed for correct usage of result field and fast resolwing in SP.
sql/item_cmpfunc.cc:
Subquery cache added.
sql/item_cmpfunc.h:
Subquery cache added.
sql/item_subselect.cc:
Subquery cache added.
sql/item_subselect.h:
Subquery cache added.
sql/item_sum.cc:
Registration of subquery parameters added.
sql/mysql_priv.h:
subquery_cache optimization option added.
sql/mysqld.cc:
subquery_cache optimization option added.
sql/opt_range.cc:
Fix due to subquery cache.
sql/opt_subselect.cc:
Parameters of the function cahnged.
sql/procedure.h:
.h file guard added.
sql/sql_base.cc:
Registration of subquery parameters added.
sql/sql_class.cc:
Option to allow add indeces to temporary table.
sql/sql_class.h:
Item iterators added.
Option to allow add indeces to temporary table.
sql/sql_expression_cache.cc:
Expression cache for caching subqueries added.
sql/sql_expression_cache.h:
Expression cache for caching subqueries added.
sql/sql_lex.cc:
Registration of subquery parameters added.
sql/sql_lex.h:
Registration of subqueries and subquery parameters added.
sql/sql_select.cc:
Subquery cache added.
sql/sql_select.h:
Subquery cache added.
sql/sql_union.cc:
A new parameter to the function added.
sql/sql_update.cc:
A new parameter to the function added.
sql/table.cc:
Procedures to manage temporarty tables index added.
sql/table.h:
Procedures to manage temporarty tables index added.
storage/maria/ha_maria.cc:
Fix of handler to allow destoy a table in case of error during the table creation.
storage/maria/ha_maria.h:
.h file guard added.
storage/myisam/ha_myisam.cc:
Fix of handler to allow destoy a table in case of error during the table creation.
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.
Fixed some bugs introduced in 5.1.47
Disabled some tests until we have merged with latest Xtradb
configure.in:
Added testing if valgrind/memcheck.h exists
storage/pbxt/src/ha_pbxt.cc:
LOCK_plugin is not anymore locked in init
Item_hex_string::Item_hex_string
The status of memory allocation in the Lex_input_stream (called
from the Parser_state constructor) was not checked which led to
a parser crash in case of the out-of-memory error.
The solution is to introduce new init() member function in
Parser_state and Lex_input_stream so that status of memory
allocation can be returned to the caller.
mysql-test/r/error_simulation.result:
Added a test case for bug #42064.
mysql-test/t/error_simulation.test:
Added a test case for bug #42064.
mysys/my_alloc.c:
Added error injection code for the regression test.
mysys/my_malloc.c:
Added error injection code for the regression test.
mysys/safemalloc.c:
Added error injection code for the regression test.
sql/event_data_objects.cc:
Use the new init() member function of Parser_state and check
its return value to handle memory allocation failures.
sql/mysqld.cc:
Added error injection code for the regression test.
sql/sp.cc:
Use the new init() member function of Parser_state and check
its return value to handle memory allocation failures.
sql/sql_lex.cc:
Moved memory allocation from constructor to the separate init()
member function.
Added error injection code for the regression test.
sql/sql_lex.h:
Moved memory allocation from constructor to the separate init()
member function.
sql/sql_parse.cc:
Use the new init() member function of Parser_state and check
its return value to handle memory allocation failures.
sql/sql_partition.cc:
Use the new init() member function of Parser_state and check
its return value to handle memory allocation failures.
sql/sql_prepare.cc:
Use the new init() member function of Parser_state and check
its return value to handle memory allocation failures.
sql/sql_trigger.cc:
Use the new init() member function of Parser_state and check
its return value to handle memory allocation failures.
sql/sql_view.cc:
Use the new init() member function of Parser_state and check
its return value to handle memory allocation failures..
sql/thr_malloc.cc:
Added error injection code for the regression test.
The problem was that a syntactically invalid trigger could cause
the server to crash when trying to list triggers. The crash would
happen due to a mishap in the backup/restore procedure that should
protect parser items which are not associated with the trigger. The
backup/restore is used to isolate the parse tree (and context) of
a statement from the load (and parsing) of a trigger. In this case,
a error during the parsing of a trigger could cause the improper
backup/restore sequence.
The solution is to properly restore the original statement context
before the parser is exited due to syntax errors in the trigger body.
mysql-test/r/trigger.result:
Add test case result for Bug#50755
mysql-test/t/trigger.test:
Add test case for Bug#50755
sql/sp_head.cc:
Merge sp_head::destroy() and sp_head destructor. Retrieve THD
from the LEX so that m_thd is not necessary.
sql/sql_lex.cc:
Explicitly restore the original environment.
Add some extra error output and code cleanup in an attempt to fix/debug
a rare random testsuite problem in check_warnings, where the exit code
from mysqltest is somehow corrupted inside mysql-test-run.pl.
include/my_global.h:
Fix compiler warnings on some platforms.
mysql-test/lib/My/SafeProcess.pm:
Move dereference of $? subprocess exit code closer to where it is generated,
to make the code more robust and on the chance that this will fix the
occasional problems in check_warnings we see in Buildbot.
mysql-test/mysql-test-run.pl:
When check_warnings failed, also log the mysqld server for which it failed.
sql/sql_lex.cc:
Fix compiler warning about possibly uninitialised value, by rewriting a for()
loop that is always executed at least once into a do .. while() loop with an
assert.
sql/table.cc:
Fix compiler warning about uninitialised value.
storage/federatedx/ha_federatedx.cc:
Fix uninitialised variable.
storage/maria/ma_delete.c:
Fix compiler warning about uninitialised value.
storage/maria/ma_loghandler.c:
Fix compiler warning about uninitialised value.
storage/myisam/ft_stopwords.c:
Fix compiler warning.
storage/myisam/mi_write.c:
Fix compiler warning about possibly uninitialised value, by rewriting a while()
loop that is always executed at least once into a do .. while() loop with an
assert.
storage/xtradb/btr/btr0cur.c:
Fix compiler warning about possibly uninitialised value.
support-files/compiler_warnings.supp:
Fix warning suppression to cover all cases in yassl.
vio/viossl.c:
Fix compiler warning.
Grouping by a subquery in a query with a distinct aggregate
function lead to a wrong result (wrong and unordered
grouping values).
There are two related problems:
1) The query like this:
SELECT (SELECT t1.a) aa, COUNT(DISTINCT b) c
FROM t1 GROUP BY aa
returned wrong result, because the outer reference "t1.a"
in the subquery was substituted with the Item_ref item.
The Item_ref item obtains data from the result_field object
that refreshes once after the end of each group. This data
is not applicable to filesort since filesort() doesn't care
about groups (and doesn't update result_field objects with
copy_fields() and so on). Also that data is not applicable
to group separation algorithm: end_send_group() checks every
record with test_if_group_changed() that evaluates Item_ref
items, but it refreshes those Item_ref-s only after the end
of group, that is a vicious circle and the grouped column
values in the output are shifted.
Fix: if
a) we grouping by a subquery and
b) that subquery has outer references to FROM list
of the grouping query,
then we substitute these outer references with
Item_direct_ref like references under aggregate
functions: Item_direct_ref obtains data directly
from the current record.
2) The query with a non-trivial grouping expression like:
SELECT (SELECT t1.a) aa, COUNT(DISTINCT b) c
FROM t1 GROUP BY aa+0
also returned wrong result, since JOIN::exec() substitutes
references to top-level aliases in SELECT list with Item_copy
caching items. Item_copy items have same refreshing policy
as Item_ref items, so the whole groping expression with
Item_copy inside returns wrong result in filesort() and
end_send_group().
Fix: include aliased items into GROUP BY item tree instead
of Item_ref references to them.
mysql-test/r/group_by.result:
Test case for bug #45640
mysql-test/t/group_by.test:
Test case for bug #45640
sql/item.cc:
Bug #45640: optimizer bug produces wrong results
Item_field::fix_fields() has been modified to resolve
aliases in GROUP BY item trees into aliased items instead
of Item_ref items.
sql/item.h:
Bug #45640: optimizer bug produces wrong results
- Item::find_item_processor() has been introduced.
- Item_ref::walk() has been modified to apply processors
to itself too (not only to referenced item).
sql/mysql_priv.h:
Bug #45640: optimizer bug produces wrong results
fix_inner_refs() has been modified to accept group_list
parameter.
sql/sql_lex.cc:
Bug #45640: optimizer bug produces wrong results
Initialization of st_select_lex::group_fix_field has
been added.
sql/sql_lex.h:
Bug #45640: optimizer bug produces wrong results
The st_select_lex::group_fix_field field has been introduced
to control alias resolution in Itef_fied::fix_fields.
sql/sql_select.cc:
Bug #45640: optimizer bug produces wrong results
- The fix_inner_refs function has been modified to treat
subquery outer references like outer fields under aggregate
functions, if they are included in GROUP BY item tree.
- The find_order_in_list function has been modified to
fix Item_field alias fields included in the GROUP BY item
trees in a special manner.
Removed compiler warnings
extra/libevent/epoll.c:
Removed compiler warnings
extra/libevent/evbuffer.c:
Removed compiler warnings
extra/libevent/event.c:
Removed compiler warnings
extra/libevent/select.c:
Removed compiler warnings
extra/libevent/signal.c:
Removed compiler warnings
include/m_ctype.h:
Define CHARSET_INFO, MY_CHARSET_HANDLER, MY_COLLATION_HANDLER, MY_UNICASE_INFO, MY_UNI_CTYPE and MY_UNI_IDX as const structures.
Declare that pointers point to const data
include/m_string.h:
Declare that pointers point to const data
include/my_sys.h:
Redefine variables and function prototypes
include/mysql.h:
Declare charset as const
include/mysql.h.pp:
Declare charset as const
include/mysql/plugin.h:
Declare charset as const
include/mysql/plugin.h.pp:
Declare charset as const
mysys/charset-def.c:
Charset can't be of type CHARSET_INFO as they are changed when they are initialized.
mysys/charset.c:
Functions that change CHARSET_INFO must use 'struct charset_info_st'
Add temporary variables to not have to change all_charsets[] (Which now is const)
sql-common/client.c:
Added cast to const
sql/item_cmpfunc.h:
Added cast to avoid compiler error.
sql/sql_class.cc:
Added cast to const
sql/sql_lex.cc:
Added cast to const
storage/maria/ma_ft_boolean_search.c:
Added cast to avoid compiler error.
storage/maria/ma_ft_parser.c:
Added cast to avoid compiler error.
storage/maria/ma_search.c:
Added cast to const
storage/myisam/ft_boolean_search.c:
Added cast to avoid compiler error
storage/myisam/ft_parser.c:
Added cast to avoid compiler error
storage/myisam/mi_search.c:
Added cast to const
storage/pbxt/src/datadic_xt.cc:
Added cast to const
storage/pbxt/src/ha_pbxt.cc:
Added cast to const
Removed compiler warning by changing prototype of XTThreadPtr()
storage/pbxt/src/myxt_xt.h:
Character sets should be const
storage/pbxt/src/xt_defs.h:
Character sets should be const
storage/xtradb/btr/btr0cur.c:
Removed compiler warning
strings/conf_to_src.c:
Added const
Functions that change CHARSET_INFO must use 'struct charset_info_st'
strings/ctype-big5.c:
Made arrays const
strings/ctype-bin.c:
Made arrays const
strings/ctype-cp932.c:
Made arrays const
strings/ctype-czech.c:
Made arrays const
strings/ctype-euc_kr.c:
Made arrays const
strings/ctype-eucjpms.c:
Made arrays const
strings/ctype-extra.c:
Made arrays const
strings/ctype-gb2312.c:
Made arrays const
strings/ctype-gbk.c:
Made arrays const
strings/ctype-latin1.c:
Made arrays const
strings/ctype-mb.c:
Made arrays const
strings/ctype-simple.c:
Made arrays const
strings/ctype-sjis.c:
Made arrays const
strings/ctype-tis620.c:
Made arrays const
strings/ctype-uca.c:
Made arrays const
strings/ctype-ucs2.c:
Made arrays const
strings/ctype-ujis.c:
Made arrays const
strings/ctype-utf8.c:
Made arrays const
strings/ctype-win1250ch.c:
Made arrays const
strings/ctype.c:
Made arrays const
Added cast to const
Functions that change CHARSET_INFO must use 'struct charset_info_st'
strings/int2str.c:
Added cast to const
* Finished Monty and Jani's merge
* Some InnoDB tests still fail (because it's old xtradb code run against
newer testsuite). They are expected to go after mergning with the latest
xtradb.
The problem is that the lexer could inadvertently skip over the
end of a query being parsed if it encountered a malformed multibyte
character. A specially crated query string could cause the lexer
to jump up to six bytes past the end of the query buffer. Another
problem was that the laxer could use unfiltered user input as
a signed array index for the parser maps (having upper and lower
bounds 0 and 256 respectively).
The solution is to ensure that the lexer only skips over well-formed
multibyte characters and that the index value of the parser maps
is always a unsigned value.
mysql-test/r/ctype_recoding.result:
Update test case result: ending backtick is not skipped over anymore.
sql/sql_lex.cc:
Characters being analyzed must be unsigned as they can be
used as indexes for the parser maps. Only skip over if the
string is a valid multi-byte sequence.
tests/mysql_client_test.c:
Add test case for Bug#45010
- Make elimination check to be able detect cases like t.primary_key_col1=othertbl.col AND t.primary_key_col2=func(t.primary_key_col1).
These are needed to handle e.g. the case of func() being a correlated subquery that selects the latest value.
- If we've removed a condition with subquery predicate, EXPLAIN [EXTENDED] won't show the subquery anymore
sql/item.cc:
MWL#17: Table elimination
- Add tem_field::check_column_usage_processor(). it allows to check which key parts a condition depends on.
sql/item.h:
MWL#17: Table elimination
- Add tem_field::check_column_usage_processor(). it allows to check which key parts a condition depends on.
sql/item_subselect.cc:
MWL#17: Table elimination
- Item_subselect got 'eliminated' attribute. It is used only to determine if the subselect should be printed by EXPLAIN.
- Item_subselect got List<Item> refers_to - a list of item in the current select that are referred to from within the subselect.
- Added Item_*::check_column_usage_processor(). it allows to check which key parts a condition depends on.
- Added a comment about possible problem in Item_subselect::walk
sql/item_subselect.h:
MWL#17: Table elimination
- Item_subselect got 'eliminated' attribute. It is used only to determine if the subselect should be printed by EXPLAIN.
- Item_subselect got List<Item> refers_to - a list of item in the current select that are referred to from within the subselect.
- Added Item_*::check_column_usage_processor(). it allows to check which key parts a condition depends on.
sql/item_sum.cc:
MWL#17: Table elimination
sql/sql_lex.cc:
MWL#17: Table elimination
sql/sql_lex.h:
MWL#17: Table elimination
sql/sql_select.h:
MWL#17: Table elimination
with gcc 4.3.2
Compiling MySQL with gcc 4.3.2 and later produces a number of
warnings, many of which are new with the recent compiler
versions.
This bug will be resolved in more than one patch to limit the
size of changesets. This is the second patch, fixing more
of the warnings.
with gcc 4.3.2
Compiling MySQL with gcc 4.3.2 and later produces a number of
warnings, many of which are new with the recent compiler
versions.
This bug will be resolved in more than one patch to limit the
size of changesets. This is the second patch, fixing more
of the warnings.
Added a more detailed error message on calling an ambiguous missing function.
mysql-test/r/ps.result:
Bug #38159: fixed existing tests
mysql-test/r/sp-error.result:
Bug #38159: test case
mysql-test/t/ps.test:
Bug #38159: fixed existing tests
mysql-test/t/sp-error.test:
Bug #38159: test case
sql/item_func.cc:
Bug #38159: generate more detailed error message
sql/share/errmsg.txt:
Bug #38159: add a more detailed error message
sql/sql_derived.cc:
Bug #38159: treat the detailed error message the same way as the
generic one
sql/sql_lex.cc:
Bug #38159:
- detect if the token is ambiguous and print the appropriate error.
- backport is_lex_native_function() from 5.1
sql/sql_lex.h:
Bug #38159: detect if the token is ambiguous and print the appropriate error.
sql/sql_yacc.yy:
Bug #38159: generate more detailed error message
sql/table.cc:
Bug #38159: treat the detailed error message the same way as the
generic one
comment can't be read back
A change to the lexer in 5.1 caused slash-asterisk-bang-version
sections to be terminated early if there exists a slash-asterisk-
style comment inside it. Nesting comments is usually illegal,
but we rely on versioned comment blocks in mysqldump, and the
contents of those sections must be allowed to have comments.
The problem was that when encountering open-comment tokens and
consuming -or- passing through the contents, the "in_comment"
state at the end was clobbered with the not-in-a-comment value,
regardless of whether we were in a comment before this or not.
So, """/*!VER one /* two */ three */""" would lose its in-comment
state between "two" and "three". Save the echo and in-comment
state, and restore it at the end of the comment if we consume a
comment.
The problem is that a SELECT .. FOR UPDATE statement might open
a table and later wait for a impeding global read lock without
noticing whether it is holding a table that is being waited upon
the the flush phase of the process that took the global read
lock.
The same problem also affected the following statements:
LOCK TABLES .. WRITE
UPDATE .. SET (update and multi-table update)
TRUNCATE TABLE ..
LOAD DATA ..
The solution is to make the above statements wait for a impending
global read lock before opening the tables. If there is no
impending global read lock, the statement raises a temporary
protection against global read locks and progresses smoothly
towards completion.
Important notice: the patch does not try to address all possible
cases, only those which are common and can be fixed unintrusively
enough for 5.0.
mysql-test/r/lock_multi.result:
Add test case result for Bug#43230
mysql-test/t/lock_multi.test:
Add test case for Bug#43230
sql/sql_lex.cc:
Initialize flag.
sql/sql_lex.h:
Add a flag to the lexer.
sql/sql_parse.cc:
Wait for the global read lock is a write lock is going to be
taken. The wait is done before opening tables.
sql/sql_yacc.yy:
Protect against the GRL if its a SELECT .. FOR UPDATE or LOCK TABLES
.. WRITE statement.