Reimplement test for MDEV-28567 such that it behaves consistently and
consistently covers the code that it was intended to cover. The test
itself moved to mdl_sync.test, because lock_sync.test is supposed for
testing THR_LOCK, not MDL. Verified with DBUG_ASSERT(0) in
open_tables() (from 92bfc0e8c4) restored.
The test is failing with various symptoms as it was designed to be
sporadic. It did cover the code that it was supposed to cover in
less than 0.1% of runs. That is the following command succeeds often
with DBUG_ASSERT(0) in open_tables() (from 92bfc0e8c4) restored:
./mtr --repeat=25 --parallel=40 lock_sync{,,,,}{,,,,}
Test is also reimplemented such that it doesn't rely on buggy "MDL
overweight" behaviour as described in MDEV-36887. Previously it did
require preceding statements that fall in deadlock in default
connection. Now it works consistently in both cases: if there was
preceding deadlock and if there was none.
mdl_after_find_deadlock sync point added to avoid premature deadlock
handling by connections that don't intend to handle it. ALTER VIEW
connection is supposed to handle it, this makes test behaviour
consistent.
Tracking history:
92bfc0e8c4 MDEV-17554, assert added
f88511647a MDEV-28567, test added, assertion modified
fe3adde250 MDEV-29060, test moved, fix attempted
8ee93b9cb4 MDEV-29060, fix attempted
611d442510 fix attempted
77c465d5aa assertion modified
4c695c85bd assertion removed
MDEV-29474 - subj
MDEV-36665 - duplicate of MDEV-29474
This was done after discussions with Igor, Sanja and Bar.
The main reason for removing the deprication was to ensure that MariaDB
is always backward compatible whenever possible.
Other things:
- Added statistics counters, mainly for the feedback plugin.
- INTO OUTFILE
- INTO variable
- If INTO is using the old syntax (end of query)
MDEV-28567 counted two execution sequences, there is third one which
executes ALTER VIEW before f() is created.
The more appropriate place for this test case is lock_sync.test
Normally we disable caching of routines in "SHOW CREATE".
Introduce an exception, if debug_dbug="+d,cache_sp_in_show_create".
lock_sync.test needs a way to populate the cache without side effects,
or else it runs into debug_sync timeouts.
So, this possibility to cache will be remain only for very special tests.
Part of MDEV-5336 Implement LOCK FOR BACKUP
Originally both table metadata lock and global read lock protection
were acquired before getting TABLE from table cache. This will be
reordered in a future commit with MDL_BACKUP_XXX locks so that we
first take table metadata lock, then get TABLE from table cache, then
acquire analogue of global read lock.
This patch both simplifies FLUSH TABLES code, makes FLUSH TABLES to
lock less and also enables FLUSH TABLES code to be used with backup
locks.
The usage of FLUSH TABLES changes slightly:
- FLUSH TABLES without any arguments will now only close not used tables
and tables locked by the FLUSH TABLES connection. All not used table
shares will be closed.
Tables locked by the FLUSH TABLES connection will be reopened and
re-locked after all others has stoped using the table (as before).
If there was no locked tables, then FLUSH TABLES is instant and will
not cause any waits.
FLUSH TABLES will not wait for any in use table.
- FLUSH TABLES with a table list, will ensure that the tables are closed
before statement returns. The code is now only using MDL locks and not
table share versions, which simplices the code greatly. One visible
change is that the server will wait for the end of the transaction that
are using the tables. Before FLUSH TABLES only waited for the statements
to end.
Signed-off-by: Monty <monty@mariadb.org>
