execute crashes server": we were deleting lex->result
after each execute, but prepared statements assumed that
it's left intact.
The fix adds cleanup() method to select_result hierarchy,
so that result objects can be reused.
Plus we now need to delete result objects more wisely.
a second time". The bug was caused by incompatibility of
negations elimination algorithm and PS: during first statement
execute a subtree with negation was replaced with equivalent
subtree without NOTs.
The problem was that although this transformation was permanent,
items of the new subtree were created in execute-local memory.
The patch adds means to check if it is the first execute of a
prepared statement, and if this is the case, to allocate items
in memory of the prepared statement.
The implementation:
- backports Item_arena from 5.0
- adds Item_arena::is_stmt_prepare(),
Item_arena::is_first_stmt_execute().
- deletes THD::allocate_temporary_pool_for_ps_preparing(),
THD::free_temporary_pool_for_ps_preparing(); they
were redundant.
and adds a few invariants:
- thd->free_list never contains junk (= freed items)
- thd->current_arena is never null. If there is no
prepared statement, it points at the thd.
The rest of the patch contains mainly mechanical changes and
cleanups.
Instead of trying to open time zone tables during calculation of CONVERT_TZ() function
or setting of @@time_zone variable we should open and lock them with the rest of
statement's table (so we should add them to global table list) and after that use such
pre-opened tables for loading info about time zones.
- client side part is simple and may be considered stable
- server side part now just joggles with THD state to save execution
state and has no additional locking wisdom.
Lot's of it are to be rewritten.
#4700 (Unsigned value returned as signed)
just no appropriate checking
#4701 (Errors returned earlier than expected)
all errors returned from send_command()
#4702 (Result isn't freed properly if there's no retrieval)
flush_use_result has only 'client' version and should
be made 'virtual'
Note: The following tests fails
- fulltext (Sergei has promised to fix)
- rpl_charset (Guilhem should fix)
- rpl_timezone (Dimitray has promised to fix)
Sanja needs to check out the calling of close_thread_tables() in sp_head.cc
work (prepared statements)" and after-review fixes:
- str_to_TIME renamed to str_to_datetime to pair with str_to_time
- functions str_to_time and str_to_TIME moved to sql-common
- send_data_str now supports MYSQL_TYPE_TIME, MYSQL_TIME_DATE,
MYSQL_TIME_DATETIME types of user input buffers.
- few more comments in the client library
- a test case added.
after Monty's review.
- Item_param was rewritten.
- it turns out that we can't convert string data to character set of
connection on the fly, because they first should be written to the binary
log.
To support efficient conversion we need to rewrite prepared statements
binlogging code first.
