when use MySQL Master -> MySQL Slave -> ClickHouse MaterializeMySQL
Engine
and MySQL Slave enable slave_parallel_worker the gtid in .metadata won't
shrink.
Like this:
https://github.com/ClickHouse/ClickHouse/issues/15951
<details>
```
drop() on T1275:
0 DB::StorageDistributed::drop (this=0x7f9ed34f0000) at ../contrib/libcxx/include/__hash_table:966
1 0x000000000d557242 in DB::DatabaseOnDisk::dropTable (this=0x7f9fc22706d8, context=..., table_name=...)
at ../contrib/libcxx/include/new:340
2 0x000000000d6fcf7c in DB::InterpreterDropQuery::executeToTable (this=this@entry=0x7f9e42560dc0, query=...)
at ../contrib/libcxx/include/memory:3826
3 0x000000000d6ff5ee in DB::InterpreterDropQuery::execute (this=0x7f9e42560dc0) at ../src/Interpreters/InterpreterDropQuery.cpp:50
4 0x000000000daa40c0 in DB::executeQueryImpl (begin=<optimized out>, end=<optimized out>, context=..., internal=<optimized out>,
stage=DB::QueryProcessingStage::Complete, has_query_tail=false, istr=0x0) at ../src/Interpreters/executeQuery.cpp:420
5 0x000000000daa59df in DB::executeQuery (query=..., context=..., internal=internal@entry=false, stage=<optimized out>,
may_have_embedded_data=<optimized out>) at ../contrib/libcxx/include/string:1487
6 0x000000000e1369e6 in DB::TCPHandler::runImpl (this=this@entry=0x7f9ddf3a9000) at ../src/Server/TCPHandler.cpp:254
7 0x000000000e1379c9 in DB::TCPHandler::run (this=0x7f9ddf3a9000) at ../src/Server/TCPHandler.cpp:1326
8 0x000000001086fac7 in Poco::Net::TCPServerConnection::start (this=this@entry=0x7f9ddf3a9000)
at ../contrib/poco/Net/src/TCPServerConnection.cpp:43
9 0x000000001086ff2b in Poco::Net::TCPServerDispatcher::run (this=0x7f9e4eba5c00)
at ../contrib/poco/Net/src/TCPServerDispatcher.cpp:114
10 0x00000000109dbe8e in Poco::PooledThread::run (this=0x7f9e4a2d2f80) at ../contrib/poco/Foundation/src/ThreadPool.cpp:199
11 0x00000000109d78f9 in Poco::ThreadImpl::runnableEntry (pThread=<optimized out>)
at ../contrib/poco/Foundation/include/Poco/SharedPtr.h:401
12 0x00007f9fc3cccea7 in start_thread (arg=<optimized out>) at pthread_create.c:477
13 0x00007f9fc3bebeaf in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95
StorageDistributedDirectoryMonitor on T166:
0 DB::StorageDistributedDirectoryMonitor::StorageDistributedDirectoryMonitor (this=0x7f9ea7ab1400, storage_=..., path_=...,
pool_=..., monitor_blocker_=..., bg_pool_=...) at ../src/Storages/Distributed/DirectoryMonitor.cpp:81
1 0x000000000dbf684e in std::__1::make_unique<> () at ../contrib/libcxx/include/memory:3474
2 DB::StorageDistributed::requireDirectoryMonitor (this=0x7f9ed34f0000, disk=..., name=...)
at ../src/Storages/StorageDistributed.cpp:682
3 0x000000000de3d5fa in DB::DistributedBlockOutputStream::writeToShard (this=this@entry=0x7f9ed39c7418, block=..., dir_names=...)
at ../src/Storages/Distributed/DistributedBlockOutputStream.cpp:634
4 0x000000000de3e214 in DB::DistributedBlockOutputStream::writeAsyncImpl (this=this@entry=0x7f9ed39c7418, block=...,
shard_id=shard_id@entry=79) at ../src/Storages/Distributed/DistributedBlockOutputStream.cpp:539
5 0x000000000de3e47b in DB::DistributedBlockOutputStream::writeSplitAsync (this=this@entry=0x7f9ed39c7418, block=...)
at ../contrib/libcxx/include/vector:1546
6 0x000000000de3eab0 in DB::DistributedBlockOutputStream::writeAsync (block=..., this=0x7f9ed39c7418)
at ../src/Storages/Distributed/DistributedBlockOutputStream.cpp:141
7 DB::DistributedBlockOutputStream::write (this=0x7f9ed39c7418, block=...)
at ../src/Storages/Distributed/DistributedBlockOutputStream.cpp:135
8 0x000000000d73b376 in DB::PushingToViewsBlockOutputStream::write (this=this@entry=0x7f9ea7a8cf58, block=...)
at ../src/DataStreams/PushingToViewsBlockOutputStream.cpp:157
9 0x000000000d7853eb in DB::AddingDefaultBlockOutputStream::write (this=0x7f9ed383d118, block=...)
at ../contrib/libcxx/include/memory:3826
10 0x000000000d740790 in DB::SquashingBlockOutputStream::write (this=0x7f9ed383de18, block=...)
at ../contrib/libcxx/include/memory:3826
11 0x000000000d68c308 in DB::CountingBlockOutputStream::write (this=0x7f9ea7ac6d60, block=...)
at ../contrib/libcxx/include/memory:3826
12 0x000000000ddab449 in DB::StorageBuffer::writeBlockToDestination (this=this@entry=0x7f9fbd56a000, block=..., table=...)
at ../src/Storages/StorageBuffer.cpp:747
13 0x000000000ddabfa6 in DB::StorageBuffer::flushBuffer (this=this@entry=0x7f9fbd56a000, buffer=...,
check_thresholds=check_thresholds@entry=true, locked=locked@entry=false, reset_block_structure=reset_block_structure@entry=false)
at ../src/Storages/StorageBuffer.cpp:661
14 0x000000000ddac415 in DB::StorageBuffer::flushAllBuffers (reset_blocks_structure=false, check_thresholds=true, this=0x7f9fbd56a000)
at ../src/Storages/StorageBuffer.cpp:605
shutdown() on T1275:
0 DB::StorageDistributed::shutdown (this=0x7f9ed34f0000) at ../contrib/libcxx/include/atomic:1612
1 0x000000000d6fd938 in DB::InterpreterDropQuery::executeToTable (this=this@entry=0x7f98530c79a0, query=...)
at ../src/Storages/TableLockHolder.h:12
2 0x000000000d6ff5ee in DB::InterpreterDropQuery::execute (this=0x7f98530c79a0) at ../src/Interpreters/InterpreterDropQuery.cpp:50
3 0x000000000daa40c0 in DB::executeQueryImpl (begin=<optimized out>, end=<optimized out>, context=..., internal=<optimized out>,
stage=DB::QueryProcessingStage::Complete, has_query_tail=false, istr=0x0) at ../src/Interpreters/executeQuery.cpp:420
4 0x000000000daa59df in DB::executeQuery (query=..., context=..., internal=internal@entry=false, stage=<optimized out>,
may_have_embedded_data=<optimized out>) at ../contrib/libcxx/include/string:1487
5 0x000000000e1369e6 in DB::TCPHandler::runImpl (this=this@entry=0x7f9ddf3a9000) at ../src/Server/TCPHandler.cpp:254
6 0x000000000e1379c9 in DB::TCPHandler::run (this=0x7f9ddf3a9000) at ../src/Server/TCPHandler.cpp:1326
7 0x000000001086fac7 in Poco::Net::TCPServerConnection::start (this=this@entry=0x7f9ddf3a9000)
at ../contrib/poco/Net/src/TCPServerConnection.cpp:43
8 0x000000001086ff2b in Poco::Net::TCPServerDispatcher::run (this=0x7f9e4eba5c00)
at ../contrib/poco/Net/src/TCPServerDispatcher.cpp:114
9 0x00000000109dbe8e in Poco::PooledThread::run (this=0x7f9e4a2d2f80) at ../contrib/poco/Foundation/src/ThreadPool.cpp:199
10 0x00000000109d78f9 in Poco::ThreadImpl::runnableEntry (pThread=<optimized out>)
at ../contrib/poco/Foundation/include/Poco/SharedPtr.h:401
11 0x00007f9fc3cccea7 in start_thread (arg=<optimized out>) at pthread_create.c:477
12 0x00007f9fc3bebeaf in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95
```
</details>
