Use local node as first priority to get Structure Of Remote Table.
we have many distributed queries( like select xx from cluster('xx',view (xxxx) ) on a clickhouse cluster. we found that the first node (shard_num=1) have 2 times of query number compared to other shards.
The reason is that the getStructureOfRemoteTableInShard func always take the first shard to execute "DESC TABLE xx" query.
The better way is to use local node as first priority which save the network rpc and reduce the pressure of first shard .
Lambda erase_from_active() captures the item (TaskRuntimeDataPtr), most
of the code path is OK, since it explicitly reset the item->task.
However one is not, when it moves the item to pending list, which will
be cleaned up when the table will be DROP/DETACH'ed, from
MergeTreeBackgroundExecutor::removeTasksCorrespondingToStorage(),
and in this case if IStorage will be already removed, then it will lead
to use-after-free on destroying the lambda, since it captures the item
by value.
And I belive that CI founds this issue here [1]:
<details>
<summary>stack trace</summary>
4 0x268d1354 in DB::ReplicatedMergeTreeQueue::CurrentlyExecuting::~CurrentlyExecuting() build_docker/../src/Storages/MergeTree/ReplicatedMergeTreeQueue.cpp:1510:33
5 0x268ead1a in std::__1::default_delete<DB::ReplicatedMergeTreeQueue::CurrentlyExecuting>::operator()(DB::ReplicatedMergeTreeQueue::CurrentlyExecuting*) const build_docker/../contrib/libcxx/include/__memory/unique_ptr.h:54:5
6 0x268ead1a in std::__1::unique_ptr<DB::ReplicatedMergeTreeQueue::CurrentlyExecuting, std::__1::default_delete<DB::ReplicatedMergeTreeQueue::CurrentlyExecuting> >::reset(DB::ReplicatedMergeTreeQueue::CurrentlyExecuting*) build_docker/../contrib/libcxx/include/__memory/unique_ptr.h:315:7
7 0x268ead1a in std::__1::unique_ptr<DB::ReplicatedMergeTreeQueue::CurrentlyExecuting, std::__1::default_delete<DB::ReplicatedMergeTreeQueue::CurrentlyExecuting> >::~unique_ptr() build_docker/../contrib/libcxx/include/__memory/unique_ptr.h:269:19
8 0x268ead1a in DB::ReplicatedMergeTreeQueue::SelectedEntry::~SelectedEntry() build_docker/../src/Storages/MergeTree/ReplicatedMergeTreeQueue.h:351:12
9 0x268ead1a in void std::__1::__destroy_at<DB::ReplicatedMergeTreeQueue::SelectedEntry, 0>(DB::ReplicatedMergeTreeQueue::SelectedEntry*) build_docker/../contrib/libcxx/include/__memory/construct_at.h:56:13
...
16 0x265e9abb in DB::MergeTreeBackgroundExecutor<DB::MergeMutateRuntimeQueue>::routine(std::__1::shared_ptr<DB::TaskRuntimeData>)::'lambda'()::~() build_docker/../src/Storages/MergeTree/MergeTreeBackgroundExecutor.cpp:127:30
17 0x265e9abb in DB::MergeTreeBackgroundExecutor<DB::MergeMutateRuntimeQueue>::routine(std::__1::shared_ptr<DB::TaskRuntimeData>) build_docker/../src/Storages/MergeTree/MergeTreeBackgroundExecutor.cpp:235:1
18 0x265ea730 in DB::MergeTreeBackgroundExecutor<DB::MergeMutateRuntimeQueue>::threadFunction() build_docker/../src/Storages/MergeTree/MergeTreeBackgroundExecutor.cpp:261:13
</details>
[1]: https://s3.amazonaws.com/clickhouse-test-reports/0/533c7888038453c047df816f3f65292cca05a54f/stateless_tests__ubsan__actions_.html
And I also I think that the following issue will also be fixed [2]:
<details>
<summary>stack trace</summary>
[ 680 ] {} <Fatal> : Logical error: 'Memory tracker: allocations not allowed.'.
...
[ 23430 ] {} <Fatal> BaseDaemon: 23. /build/build_docker/../src/Common/formatReadable.cpp:46: formatReadableSizeWithBinarySuffix(double, int) @ 0x1713bb98 in /usr/bin/clickhouse
...
[ 23430 ] {} <Fatal> BaseDaemon: 31. ../src/Common/MemoryTracker.cpp:112: MemoryTracker::logPeakMemoryUsage() @ 0x170e0ab9 in /usr/bin/clickhouse
[ 23430 ] {} <Fatal> BaseDaemon: 32. /build/build_docker/../src/Common/MemoryTracker.cpp:98: MemoryTracker::~MemoryTracker() @ 0x170e063a in /usr/bin/clickhouse
[ 23430 ] {} <Fatal> BaseDaemon: 33. /build/build_docker/../src/Storages/MergeTree/MergeList.cpp:144: DB::MergeListElement::~MergeListElement() @ 0x279fb290 in /usr/bin/clickhouse
...
[ 23430 ] {} <Fatal> BaseDaemon: 38. /build/build_docker/../src/Storages/MergeTree/BackgroundProcessList.h:41: DB::BackgroundProcessListEntry<DB::MergeListElement, DB::MergeInfo>::~BackgroundProcessListEntry() @ 0x276ce6c7 in /usr/bin/clickhouse
[ 23430 ] {} <Fatal> BaseDaemon: 39. /build/build_docker/../contrib/libcxx/include/__memory/unique_ptr.h:54: std::__1::default_delete<DB::BackgroundProcessListEntry<DB::MergeListElement, DB::MergeInfo> >::operator()(DB::BackgroundProcessListEntry<DB::MergeListElement, DB::MergeInfo>*) const @ 0x276ce60b in /usr/bin/clickhouse
[ 23430 ] {} <Fatal> BaseDaemon: 40. /build/build_docker/../contrib/libcxx/include/__memory/unique_ptr.h:316: std::__1::unique_ptr<DB::BackgroundProcessListEntry<DB::MergeListElement, DB::MergeInfo>, std::__1::default_delete<DB::BackgroundProcessListEntry<DB::MergeListElement, DB::MergeInfo> > >::reset(DB::BackgroundProcessListEntry<DB::MergeListElement, DB::MergeInfo>*) @ 0x276ce57c in /usr/bin/clickhouse
[ 23430 ] {} <Fatal> BaseDaemon: 41. /build/build_docker/../contrib/libcxx/include/__memory/unique_ptr.h:269: std::__1::unique_ptr<DB::BackgroundProcessListEntry<DB::MergeListElement, DB::MergeInfo>, std::__1::default_delete<DB::BackgroundProcessListEntry<DB::MergeListElement, DB::MergeInfo> > >::~unique_ptr() @ 0x276ce399 in /usr/bin/clickhouse
[ 23430 ] {} <Fatal> BaseDaemon: 42. /build/build_docker/../src/Storages/MergeTree/MutatePlainMergeTreeTask.h:22: DB::MutatePlainMergeTreeTask::~MutatePlainMergeTreeTask() @ 0x27defceb in /usr/bin/clickhouse
[ 23430 ] {} <Fatal> BaseDaemon: 43. /build/build_docker/../contrib/libcxx/include/__memory/construct_at.h:57: void std::__1::__destroy_at<DB::MutatePlainMergeTreeTask, 0>(DB::MutatePlainMergeTreeTask*) @ 0x27dd69c1 in /usr/bin/clickhouse
[ 23430 ] {} <Fatal> BaseDaemon: 44. /build/build_docker/../contrib/libcxx/include/__memory/construct_at.h:82: void std::__1::destroy_at<DB::MutatePlainMergeTreeTask, 0>(DB::MutatePlainMergeTreeTask*) @ 0x27dd6955 in /usr/bin/clickhouse
[ 23430 ] {} <Fatal> BaseDaemon: Integrity check of the executable skipped because the reference checksum could not be read. (calculated checksum: 91F5937571C11255DFE73230B52CE9C0)
[ 602 ] {} <Fatal> Application: Child process was terminated by signal 6.
</details>
[2]: https://s3.amazonaws.com/clickhouse-test-reports/39222/a068c397dfd7943359a8b554566c3c70b78baf8d/stateless_tests__debug__actions__%5B1/3%5D.html
Refs: https://github.com/ClickHouse/ClickHouse/pull/29614#discussion_r720455032 (cc @nikitamikhaylov)
Signed-off-by: Azat Khuzhin <a.khuzhin@semrush.com>
