Fix three compilation warnings.

into  moonlight.home:/home/tomash/src/mysql_ab/mysql-5.1-wl3698

BUG#26429: SHOW CREATE EVENT is incorrect for an event that
           STARTS NOW()
BUG#26431: Impossible to re-create an event from backup if its
           STARTS clause is in the past
WL#3698: Events: execution in local time zone

The problem was that local times specified by the user in AT, STARTS
and ENDS of CREATE EVENT/ALTER EVENT statement were converted to UTC,
and the original time zone was forgotten.  This way, event scheduler
couldn't honor Daylight Saving Time shifts, and times shown to the
user were also in UTC.  Additionally, CREATE EVENT didn't allow times
in the past, thus preventing straightforward event restoration from
old backups.

This patch reworks event scheduler time computations, performing them
in the time zone associated with the event.  Also it allows times to
be in the past.

The patch adds time_zone column to mysql.event table.

NOTE: The patch is almost final, but the bug#9953 should be pushed
first.

into  kpdesk.mysql.com:/home/thek/dev/mysql-5.1-runtime

- Crash occured because Event engine is only initialized if
  ACLs are used but not properly marked as disabled.
- The patch is to mark the Event engine as DISABLED if no ACLs
  are used to avoid access of uninitialized variables.

Fix a typo (togheter -> together)

into  gbichot3.local:/home/mysql_src/mysql-5.1-runtime-735-realfix

into  weblab.(none):/home/marcsql/TREE/mysql-5.1-26503-merge

into  weblab.(none):/home/marcsql/TREE/mysql-5.0-26503

Before this fix, the parser would accept illegal code in SQL exceptions
handlers, that later causes the runtime to crash when executing the code,
due to memory violations in the exception handler stack.

The root cause of the problem is instructions within an exception handler
that jumps to code located outside of the handler. This is illegal according
to the SQL 2003 standard, since labels located outside the handler are not
supposed to be visible (they are "out of scope"), so any instruction that
jumps to these labels, like ITERATE or LEAVE, should not parse.

The section of the standard that is relevant for this is :
  SQL:2003 SQL/PSM (ISO/IEC 9075-4:2003)
  section 13.1 <compound statement>,
  syntax rule 4
<quote>
  The scope of the <beginning label> is CS excluding every <SQL schema
  statement> contained in CS and excluding every
  <local handler declaration list> contained in CS. <beginning label> shall
  not be equivalent to any other <beginning label>s within that scope.
</quote>

With this fix, the C++ class sp_pcontext, which represent the "parsing
context" tree (a.k.a symbol table) of a stored procedure, has been changed
as follows:
- constructors have been cleaned up, so that only building a root node for
the tree is public; building nodes inside a tree is not public.
- a new member, m_label_scope, indicates if a given syntactic context
belongs to a DECLARE HANDLER block,
- label resolution, in the method find_label(), has been changed to
implement the restriction of scope regarding labels used in a compound
statement.

The actions in the parser, when parsing the body of a SQL exception handler,
have been changed as follows:
- the implementation of an exception handler (DECLARE HANDLER) now creates
explicitly a new sp_pcontext, to isolate the code inside the handler from
the containing compound statement context.
- registering exception handlers as a result occurs in the parent context,
see the rule sp_hcond_element
- the code in sp_hcond_list has been cleaned up, to avoid code duplication

In addition, the flags IN_SIMPLE_CASE and IN_HANDLER, declared in sp_head.h
have been removed, since they are unused and broken by design (as seen with
Bug 19194 (Right recursion in parser for CASE causes excessive stack usage,
limitation), representing a stack in a single flag is not possible.

Tests in sp-error have been added to show that illegal constructs are now
rejected.

Tests in sp have been added for code coverage, to show that ITERATE or LEAVE
statements are legal when jumping to a label in scope, inside the body of
an exception handler.

lock table for writing during prepare of statement.

When single call open_normal_and_derived_tables() was used, we never
set table_count to the right value.  This patch reverts the part of
the old code that does open_tables() (and sets table_count), then
checks if table_list->multitable_view is set (and returns if so, using
table_count value), and only then it does mysql_handle_derived().

into  moonlight.home:/home/tomash/src/mysql_ab/mysql-5.1-bug16425

Cache".
WL#1569 "Prepared Statements: implement support of Query Cache".
Prepared SELECTs did not look up in the query cache, and their results
were not stored in the query cache. This made them slower than
non-prepared SELECTs in some cases.
The fix is to re-use the expanded query (the prepared query where
"?" placeholders are replaced by their values, at execution time)
for searching/storing in the query cache.
It works fine for statements prepared via mysql_stmt_prepare(), which
are the most commonly used and were the scope of this bugfix and WL.
It works less fine for statements prepared via the SQL command
PREPARE...FROM, which are still not using the query cache if they
have at least one parameter (because then the expanded query contains
names of user variables, and user variables don't work with the
query cache, even in non-prepared queries).
Note that results from prepared SELECTs, which are in the binary
protocol, and results from normal SELECTs, which are in the text
protocol, ignore each other in the query cache, because a result in the
binary protocol should never be served to a SELECT expecting the text
protocol and vice-versa.
Note, after this patch, bug 25843 starts applying to query cache
("changing default database between PREPARE and EXECUTE of statement
breaks binlog"), we need to fix it.

for bug#16425: Events: no DEFINER clause.  The problem was that there
were two rules

  ALTER view_algorithm_opt definer ... VIEW ...
  ALTER definer EVENT ...

so when there was 'ALTER definer' in the input it was unclear if empty
view_algorithm_opt should be executed or not.

We solve this by introducing three distinct rules

  ALTER view_algorithm definer ... VIEW ...
  ALTER definer ... VIEW ...
  ALTER definer EVENT ...

that remove the ambiguity.

into  moonlight.home:/home/tomash/src/mysql_ab/mysql-5.1-bug9953

The problem was that some facilities (like CONVERT_TZ() function or
server HELP statement) may require implicit access to some tables in
'mysql' database.  This access was done by ordinary means of adding
such tables to the list of tables the query is going to open.
However, if we issued LOCK TABLES before that, we would get "table
was not locked" error trying to open such implicit tables.

The solution is to treat certain tables as MySQL system tables, like
we already do for mysql.proc.  Such tables may be opened for reading
at any moment regardless of any locks in effect.  The cost of this is
that system table may be locked for writing only together with other
system tables, it is disallowed to lock system tables for writing and
have any other lock on any other table.

After this patch the following tables are treated as MySQL system
tables:
  mysql.help_category
  mysql.help_keyword
  mysql.help_relation
  mysql.help_topic
  mysql.proc (it already was)
  mysql.time_zone
  mysql.time_zone_leap_second
  mysql.time_zone_name
  mysql.time_zone_transition
  mysql.time_zone_transition_type

These tables are now opened with open_system_tables_for_read() and
closed with close_system_tables(), or one table may be opened with
open_system_table_for_update() and closed with close_thread_tables()
(the latter is used for mysql.proc table, which is updated as part of
normal MySQL server operation).  These functions may be used when
some tables were opened and locked already.

NOTE: online update of time zone tables is not possible during
replication, because there's no time zone cache flush neither on LOCK
TABLES, nor on FLUSH TABLES, so the master may serve stale time zone
data from cache, while on slave updated data will be loaded from the
time zone tables.

into  moonlight.home:/home/tomash/src/mysql_ab/mysql-5.0-bug20492

into  moonlight.home:/home/tomash/src/mysql_ab/mysql-5.1-bug20492

to a pointer to object, that is, int foo(); void *bar= (void*) foo
is not allowed.

into  weblab.(none):/home/marcsql/TREE/mysql-5.1-8407-cleanup

Bug 8407, post review cleanup: use instr::get_cont_dest() to get the instruction
continuation instruction, for CONTINUE exception handlers.

into  moonlight.home:/home/tomash/src/mysql_ab/mysql-5.1-bug18326

During statement prepare phase the tables were locked as if the
statement is being executed, however this is not necessary.

The solution is to not lock tables on statement prepare phase.
Opening tables is enough to prevent DDL on them, and during statement
prepare we do not access nor modify any data.

into  bodhi.local:/opt/local/work/mysql-5.1-runtime

into  bodhi.local:/opt/local/work/mysql-5.1-runtime

into  bodhi.local:/opt/local/work/mysql-5.0-26750

fixes).

The legend: on a replication slave, in case a trigger creation
was filtered out because of application of replicate-do-table/
replicate-ignore-table rule, the parsed definition of a trigger was not 
cleaned up properly. LEX::sphead member was left around and leaked 
memory. Until the actual implementation of support of 
replicate-ignore-table rules for triggers by the patch for Bug 24478 it 
was never the case that "case SQLCOM_CREATE_TRIGGER"
was not executed once a trigger was parsed,
so the deletion of lex->sphead there worked and the memory did not leak.

The fix: 

The real cause of the bug is that there is no 1 or 2 places where
we can clean up the main LEX after parse. And the reason we 
can not have just one or two places where we clean up the LEX is
asymmetric behaviour of MYSQLparse in case of success or error. 

One of the root causes of this behaviour is the code in Item::Item()
constructor. There, a newly created item adds itself to THD::free_list
- a single-linked list of Items used in a statement. Yuck. This code
is unaware that we may have more than one statement active at a time,
and always assumes that the free_list of the current statement is
located in THD::free_list. One day we need to be able to explicitly
allocate an item in a given Query_arena.
Thus, when parsing a definition of a stored procedure, like
CREATE PROCEDURE p1() BEGIN SELECT a FROM t1; SELECT b FROM t1; END;
we actually need to reset THD::mem_root, THD::free_list and THD::lex
to parse the nested procedure statement (SELECT *).
The actual reset and restore is implemented in semantic actions
attached to sp_proc_stmt grammar rule.
The problem is that in case of a parsing error inside a nested statement
Bison generated parser would abort immediately, without executing the
restore part of the semantic action. This would leave THD in an 
in-the-middle-of-parsing state.
This is why we couldn't have had a single place where we clean up the LEX
after MYSQLparse - in case of an error we needed to do a clean up
immediately, in case of success a clean up could have been delayed.
This left the door open for a memory leak.

One of the following possibilities were considered when working on a fix:
- patch the replication logic to do the clean up. Rejected
as breaks module borders, replication code should not need to know the
gory details of clean up procedure after CREATE TRIGGER.
- wrap MYSQLparse with a function that would do a clean up.
Rejected as ideally we should fix the problem when it happens, not
adjust for it outside of the problematic code.
- make sure MYSQLparse cleans up after itself by invoking the clean up
functionality in the appropriate places before return. Implemented in 
this patch.
- use %destructor rule for sp_proc_stmt to restore THD - cleaner
than the prevoius approach, but rejected
because needs a careful analysis of the side effects, and this patch is 
for 5.0, and long term we need to use the next alternative anyway
- make sure that sp_proc_stmt doesn't juggle with THD - this is a 
large work that will affect many modules.

Cleanup: move main_lex and main_mem_root from Statement to its
only two descendants Prepared_statement and THD. This ensures that
when a Statement instance was created for purposes of statement backup,
we do not involve LEX constructor/destructor, which is fairly expensive.
In order to track that the transformation produces equivalent 
functionality please check the respective constructors and destructors
of Statement, Prepared_statement and THD - these members were
used only there.
This cleanup is unrelated to the patch.

into  weblab.(none):/home/marcsql/TREE/mysql-5.1-8407-merge

into  weblab.(none):/home/marcsql/TREE/mysql-5.0-8407_b

into  weblab.(none):/home/marcsql/TREE/mysql-5.1-8407-merge