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| author | Alexey Botchkov <holyfoot@askmonty.org> | 2013-04-12 18:06:51 +0500 |
|---|---|---|
| committer | Alexey Botchkov <holyfoot@askmonty.org> | 2013-04-12 18:06:51 +0500 |
| commit | 1a600125ff77b57f6bcb57ba2fff45293ab7257d (patch) | |
| tree | 765189555c7cc611e4f635822f705a95876cca9f /sql/sql_reload.cc | |
| parent | ff3407a111ec268e7bd5e726a75527089871c914 (diff) | |
| download | mariadb-git-1a600125ff77b57f6bcb57ba2fff45293ab7257d.tar.gz | |
MDEV-3917 multiple use locks (GET_LOCK) in one connection.
The patch contributed by Konstantin Osipov applied.
Native comments:
Implement multiple user-level locks per connection.
GET_LOCK() function in MySQL allows a connection to hold at most
one user level lock. Taking a new lock automatically releases the
old lock, if any.
The limit of one lock per session existed since early versions
of MySQL didn't have a deadlock detector for SQL locks.
MDL patches in MySQL 5.5 added a deadlock detector,
so starting from 5.5 it became possible to take multiple locks
in any order -- a deadlock, should it occur, would be detected
and an error returned to the client which closed the wait chain.
This is exactly what is done in this patch: ULLs are moved
to use MDL subsystem.
Diffstat (limited to 'sql/sql_reload.cc')
| -rw-r--r-- | sql/sql_reload.cc | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/sql/sql_reload.cc b/sql/sql_reload.cc index 2720dc7cd74..e9c9dc86e41 100644 --- a/sql/sql_reload.cc +++ b/sql/sql_reload.cc @@ -205,6 +205,7 @@ bool reload_acl_and_cache(THD *thd, unsigned long options, DBUG_ASSERT(!thd || thd->locked_tables_mode || !thd->mdl_context.has_locks() || thd->handler_tables_hash.records || + thd->ull_hash.records || thd->global_read_lock.is_acquired()); /* |