diff options
Diffstat (limited to 'sql/mdl.h')
| -rw-r--r-- | sql/mdl.h | 23 |
1 files changed, 18 insertions, 5 deletions
diff --git a/sql/mdl.h b/sql/mdl.h index e0934cb732b..39e47da61dd 100644 --- a/sql/mdl.h +++ b/sql/mdl.h @@ -152,11 +152,24 @@ enum enum_mdl_type { /** Duration of metadata lock. */ -enum enum_mdl_duration { MDL_STATEMENT= 0, - MDL_TRANSACTION, - MDL_EXPLICIT, - /* This should be the last ! */ - MDL_DURATION_END }; +enum enum_mdl_duration { + /** + Locks with statement duration are automatically released at the end + of statement or transaction. + */ + MDL_STATEMENT= 0, + /** + Locks with transaction duration are automatically released at the end + of transaction. + */ + MDL_TRANSACTION, + /** + Locks with explicit duration survive the end of statement and transaction. + They have to be released explicitly by calling MDL_context::release_lock(). + */ + MDL_EXPLICIT, + /* This should be the last ! */ + MDL_DURATION_END }; /** Maximal length of key for metadata locking subsystem. */ |