mirrors/dragonfly
1
0
Fork 0
mirror of https://github.com/dragonflydb/dragonfly.git synced 2025-05-10 18:05:44 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions 5

chore: lock keys for optimistic transactions (#3865)

Browse source 
We do not acquire any locks for transactions that are executing optimistically. However, this is problematic for callbacks that need to preempt (e.g. because a journal is active).

---------

Signed-off-by: kostas <kostas@dragonflydb.io>
This commit is contained in:
Kostas Kyrimis 2024-10-08 14:25:36 +03:00 • committed by GitHub
parent dac1b0f3ca
commit c1e9d510a3
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
1 changed files with 23 additions and 24 deletions
Download patch file Download diff file Expand all files Collapse all files

47
src/server/transaction.cc
View file

@ -83,14 +83,6 @@ uint16_t trans_id(const Transaction* ptr) {
return (intptr_t(ptr) >> 8) & 0xFFFF; return (intptr_t(ptr) >> 8) & 0xFFFF;
} }
bool CheckLocks(const DbSlice& db_slice, IntentLock::Mode mode, const KeyLockArgs& lock_args) {
for (LockFp fp : lock_args.fps) {
if (!db_slice.CheckLock(mode, lock_args.db_index, fp))
return false;
}
return true;
}
struct ScheduleContext { struct ScheduleContext {
Transaction* trans; Transaction* trans;
bool optimistic_execution = false; bool optimistic_execution = false;
@ -1052,25 +1044,18 @@ bool Transaction::ScheduleInShard(EngineShard* shard, bool execute_optimistic) {
if (txid_ > 0 && shard->committed_txid() >= txid_) if (txid_ > 0 && shard->committed_txid() >= txid_)
return false; return false;
auto release_fp_locks = [&]() {
GetDbSlice(shard->shard_id()).Release(mode, lock_args);
sd.local_mask &= ~KEYLOCK_ACQUIRED;
};
// Acquire intent locks. Intent locks are always acquired, even if already locked by others. // Acquire intent locks. Intent locks are always acquired, even if already locked by others.
if (!IsGlobal()) { if (!IsGlobal()) {
lock_args = GetLockArgs(shard->shard_id()); lock_args = GetLockArgs(shard->shard_id());
bool shard_unlocked = shard->shard_lock()->Check(mode); bool shard_unlocked = shard->shard_lock()->Check(mode);
// Check if we can run immediately // We need to acquire the fp locks because the executing callback
if (shard_unlocked && execute_optimistic && // within RunCallback below might preempt.
CheckLocks(GetDbSlice(shard->shard_id()), mode, lock_args)) {
sd.local_mask |= OPTIMISTIC_EXECUTION;
shard->stats().tx_optimistic_total++;
RunCallback(shard);
// Check state again, it could've been updated if the callback returned AVOID_CONCLUDING flag.
// Only possible for single shard.
if (coordinator_state_ & COORD_CONCLUDING)
return true;
}
bool keys_unlocked = GetDbSlice(shard->shard_id()).Acquire(mode, lock_args); bool keys_unlocked = GetDbSlice(shard->shard_id()).Acquire(mode, lock_args);
lock_granted = shard_unlocked && keys_unlocked; lock_granted = shard_unlocked && keys_unlocked;
@ -1080,6 +1065,21 @@ bool Transaction::ScheduleInShard(EngineShard* shard, bool execute_optimistic) {
} }
DVLOG(3) << "Lock granted " << lock_granted << " for trans " << DebugId(); DVLOG(3) << "Lock granted " << lock_granted << " for trans " << DebugId();
// Check if we can run immediately
if (shard_unlocked && execute_optimistic && lock_granted) {
sd.local_mask |= OPTIMISTIC_EXECUTION;
shard->stats().tx_optimistic_total++;
RunCallback(shard);
// Check state again, it could've been updated if the callback returned AVOID_CONCLUDING flag.
// Only possible for single shard.
if (coordinator_state_ & COORD_CONCLUDING) {
release_fp_locks();
return true;
}
}
} }
// Single shard operations might have delayed acquiring txid unless neccessary. // Single shard operations might have delayed acquiring txid unless neccessary.
@ -1095,8 +1095,7 @@ bool Transaction::ScheduleInShard(EngineShard* shard, bool execute_optimistic) {
// fail this scheduling attempt for trans. // fail this scheduling attempt for trans.
if (!txq->Empty() && txid_ < txq->TailScore() && !lock_granted) { if (!txq->Empty() && txid_ < txq->TailScore() && !lock_granted) {
if (sd.local_mask & KEYLOCK_ACQUIRED) { if (sd.local_mask & KEYLOCK_ACQUIRED) {
GetDbSlice(shard->shard_id()).Release(mode, lock_args); release_fp_locks();
sd.local_mask &= ~KEYLOCK_ACQUIRED;
} }
return false; return false;
} }