and some SP-related cleanups.
- We don't have separate stage for calculation of list of tables
to be prelocked and doing implicit LOCK/UNLOCK any more.
Instead we calculate this list at open_tables() and do implicit
LOCK in lock_tables() (and UNLOCK in close_thread_tables()).
Also now we support cases when same table (with same alias) is
used several times in the same query in SP.
- Cleaned up execution of SP. Moved all common code which handles
LEX and does preparations before statement execution or complex
expression evaluation to auxilary sp_lex_keeper class. Now
all statements in SP (and corresponding instructions) that
evaluate expression which can contain subquery have their
own LEX.
Collect all tables and SPs refered by a statement, and open all tables
with an implicit LOCK TABLES. Do find things refered by triggers and views,
we open them first (and then repeat this until nothing new is found), before
doing the actual lock tables.
Phase 2: Make SPs belong to a DB, and use qualified names.
As a side effect, using USE in an SP is no longer allowed.
(It just doesn't work otherwise.)
make characteristics (and SHOW) work right, we had to separate the old
definition blob in the mysql.proc table into separate fields for parameters,
return type, and body, and handle the characteristics (like SQL SECURITY)
separately... and then reassemble the CREATE string for parsing, of course.
This is rather ugly, mostly the parser bit. (Hopefully that will be better
with the new parser.)
Expanded the mysql.proc table, reworked the find/create/drop functions
completely, added new functions for FUNCTIONs (lotta functions here :),
got rid of some unnecessary use of Item_strings while at it. Extended
the parser correspondingly, and fiddled around a bit to make SP FUNCTIONs
coexist with UDFs.
Can now CREATE and DROP FUNCTIONs. Invoking yet to come...
Fixed backpatching of forward jumps.
Implemented LOOP, WHILE, REPEAT (temporarily known as SPREPEAT).
Known bug: Expression evaluation still not quite ok (e.g. "x > 0"),
which is why IF and CASE is not yet implemented.
