Commit c3c2ffe2 by Julien Muchembled

mysql: do not use unsafe TRUNCATE statement

TRUNCATE was chosen for performance reasons, but it's usually done on small
tables, and not for performance-critical operations. TRUNCATE commits
implicitely, so for pt/ttrans in particular, it's certainly slower due to extra
fsyncs to disk.

On the other side, committing too early can corrupt the database if the storage
node is stopped just after. For example, a failure in changePartitionTable()
can cause 'pt' to remain empty.
1 parent e25fa5d9
Pipeline #1318 for c3c2ffe2 skipped in 0 seconds
...@@ -136,7 +136,7 @@ class MySQLDatabaseManager(DatabaseManager): ...@@ -136,7 +136,7 @@ class MySQLDatabaseManager(DatabaseManager):
if r in ("INSERT", "REPLACE", "DELETE", "UPDATE"): if r in ("INSERT", "REPLACE", "DELETE", "UPDATE"):
self._active = 1 self._active = 1
else: else:
assert r in ("ALTER", "CREATE", "DROP", "TRUNCATE"), query assert r in ("ALTER", "CREATE", "DROP"), query
@property @property
def escape(self): def escape(self):
...@@ -364,7 +364,7 @@ class MySQLDatabaseManager(DatabaseManager): ...@@ -364,7 +364,7 @@ class MySQLDatabaseManager(DatabaseManager):
offset_list = [] offset_list = []
q = self.query q = self.query
if reset: if reset:
q("TRUNCATE pt") q("DELETE FROM pt")
for offset, nid, state in cell_list: for offset, nid, state in cell_list:
# TODO: this logic should move out of database manager # TODO: this logic should move out of database manager
# add 'dropCells(cell_list)' to API and use one query # add 'dropCells(cell_list)' to API and use one query
...@@ -414,8 +414,8 @@ class MySQLDatabaseManager(DatabaseManager): ...@@ -414,8 +414,8 @@ class MySQLDatabaseManager(DatabaseManager):
def dropUnfinishedData(self): def dropUnfinishedData(self):
q = self.query q = self.query
data_id_list = [x for x, in q("SELECT data_id FROM tobj") if x] data_id_list = [x for x, in q("SELECT data_id FROM tobj") if x]
q("TRUNCATE tobj") q("DELETE FROM tobj")
q("TRUNCATE ttrans") q("DELETE FROM ttrans")
self.releaseData(data_id_list, True) self.releaseData(data_id_list, True)
def storeTransaction(self, tid, object_list, transaction, temporary = True): def storeTransaction(self, tid, object_list, transaction, temporary = True):
......
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