There are two TABLE objects in each thread: first one is created in
delayed thread by Delayed_insert::open_and_lock_table(), second one is
created in connection thread by Delayed_insert::get_local_table(). It
is copied from the delayed thread table.
When the second table is copied copy-assignment operator copies
vcol_refix_list which is already filled with an item from delayed
thread. Then get_local_table() adds its own item. Thus both tables
contains the same list with two items which is wrong. Then connection
thread finishes and its item freed. Then delayed thread tries to
access it in vcol_cleanup_expr().
The fix just clears vcol_refix_list in the copied table.
Another problem is that copied table contains the same mem_root, any
allocations on it will be invalid if the original table is freed (and
that is indeterministic as it is done in another thread). Since copied
table is allocated in connection THD and lives not longer than
thd->mem_root we may assign its mem_root from thd->mem_root.
Third, it doesn't make sense to do open_and_lock_tables() on NULL
pointer.
* invoke check_expression() for all vcol_info's in
mysql_prepare_create_table() to check for FK CASCADE
* also check for SET NULL and SET DEFAULT
* to check against existing FKs when a vcol is added in ALTER TABLE,
old FKs must be added to the new_key_list just like other indexes are
* check columns recursively, if vcol1 references vcol2,
flags of vcol2 must be taken into account
* remove check_table_name_processor(), put that logic under
check_vcol_func_processor() to avoid walking the tree twice
Restrict vcol_cleanup_expr() in close_thread_tables() to only simple
locked tables mode. Prelocked is cleaned up like normal statement: in
close_thread_table().
On create table tmp as select ... we exited Item_func::fix_fields()
with error. fix_fields_if_needed('foo' or 'bar') failed and we
returned true, but already changed const_item_cache. So the item is in
inconsistent state: fixed == false and const_item_cache == false.
Now we cleanup the item before the return if Item_func::fix_fields()
fails to process.
column generated using date_format() and if()
vcol_info->expr is allocated on expr_arena at parsing stage. Since
expr item is allocated on expr_arena all its containee items must be
allocated on expr_arena too. Otherwise fix_session_expr() will
encounter prematurely freed item.
When table is reopened from cache vcol_info contains stale
expression. We refresh expression via TABLE::vcol_fix_exprs() but
first we must prepare a proper context (Vcol_expr_context) which meets
some requirements:
1. As noted above expr update must be done on expr_arena as there may
be new items created. It was a bug in fix_session_expr_for_read() and
was just not reproduced because of no second refix. Now refix is done
for more cases so it does reproduce. Tests affected: vcol.binlog
2. Also name resolution context must be narrowed to the single table.
Tested by: vcol.update main.default vcol.vcol_syntax gcol.gcol_bugfixes
3. sql_mode must be clean and not fail expr update.
sql_mode such as MODE_NO_BACKSLASH_ESCAPES, MODE_NO_ZERO_IN_DATE, etc
must not affect vcol expression update. If the table was created
successfully any further evaluation must not fail. Tests affected:
main.func_like
Reviewed by: Sergei Golubchik <serg@mariadb.org>
Before FRM is written walk vcol expressions through
check_table_name_processor() and check if field items match (db,
table_name) qualifier.
We cannot do this in check_vcol_func_processor() as there is already
no table name qualifiers in expressions of written and loaded FRM.
