yiguolei commented on code in PR #21969:
URL: https://github.com/apache/doris/pull/21969#discussion_r1270844337
##########
be/src/olap/tablet_manager.cpp:
##########
@@ -244,7 +244,18 @@ Status TabletManager::create_tablet(const
TCreateTabletReq& request, std::vector
int64_t tablet_id = request.tablet_id;
LOG(INFO) << "begin to create tablet. tablet_id=" << tablet_id;
- std::lock_guard<std::shared_mutex>
wrlock(_get_tablets_shard_lock(tablet_id));
+ // when we create rollup tablet A(assume on shard-1) from tablet B(assume
on shard-2)
+ // we need use write lock on shard-1 and then use read lock on shard-2
+ // if there have create rollup tablet C(assume on shard-2) from tablet
D(assume on shard-1) at the same time, we will meet deadlock
+ std::unique_lock two_tablet_lock(_two_tablet_mtx, std::defer_lock);
+ bool is_schema_change = request.__isset.base_tablet_id &&
request.base_tablet_id > 0;
+ bool need_two_lock = is_schema_change && ((_tablets_shards_mask &
request.base_tablet_id) !=
+ (_tablets_shards_mask &
tablet_id));
+ if (need_two_lock) {
+ two_tablet_lock.lock();
Review Comment:
这样会导致并发度很低，tablet map lock 分shard 就没啥意义了。 相当于建rollup 变成顺序的了
##########
be/src/olap/tablet_manager.cpp:
##########
@@ -244,7 +244,18 @@ Status TabletManager::create_tablet(const
TCreateTabletReq& request, std::vector
int64_t tablet_id = request.tablet_id;
LOG(INFO) << "begin to create tablet. tablet_id=" << tablet_id;
- std::lock_guard<std::shared_mutex>
wrlock(_get_tablets_shard_lock(tablet_id));
+ // when we create rollup tablet A(assume on shard-1) from tablet B(assume
on shard-2)
+ // we need use write lock on shard-1 and then use read lock on shard-2
+ // if there have create rollup tablet C(assume on shard-2) from tablet
D(assume on shard-1) at the same time, we will meet deadlock
+ std::unique_lock two_tablet_lock(_two_tablet_mtx, std::defer_lock);
+ bool is_schema_change = request.__isset.base_tablet_id &&
request.base_tablet_id > 0;
+ bool need_two_lock = is_schema_change && ((_tablets_shards_mask &
request.base_tablet_id) !=
+ (_tablets_shards_mask &
tablet_id));
+ if (need_two_lock) {
+ two_tablet_lock.lock();
Review Comment:
这样会导致并发度很低，tablet map lock 分shard 就没啥意义了。 相当于建rollup 变成顺序的了
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