In the member function insert(position, elem) to class Block, if function checkColumnStructure<void> throws an exception for columns with same name but unidentical structure, it will result in the mismatch between index_by_name and data. However we could not presume upon that caller will not use this block object anymore. So it seems better to guarantee consistency innerly.
Do not stop processing pathologically slow queries,
since this may hide errors in other queries,
i.e. when the test failed on one of servers (upstream or from PR)
and someone interpret this is as OK with the following comment:
"the failure was on the upstream server it is OK, PR should fix it"
Anyway there is almost zero such queries right now, and before merging
something this should be reviewed.
Stress tests founds [1]:
==527==WARNING: MemorySanitizer: use-of-uninitialized-value
0 0x37078ffd in unsigned long std::__1::__cxx_atomic_fetch_add<unsigned long>(std::__1::__cxx_atomic_base_impl<unsigned long>*, unsigned long, std::__1::memory_order) obj-x86_64-linux-gnu/../contrib/libcxx/include/atomic:1050:12
1 0x37078ffd in std::__1::__atomic_base<unsigned long, true>::fetch_add(unsigned long, std::__1::memory_order) obj-x86_64-linux-gnu/../contrib/libcxx/include/atomic:1719:17
2 0x37078ffd in std::__1::__atomic_base<unsigned long, true>::operator++() obj-x86_64-linux-gnu/../contrib/libcxx/include/atomic:1756:57
3 0x37078ffd in SimpleIncrement::get() obj-x86_64-linux-gnu/../src/Common/SimpleIncrement.h:20:16
4 0x37078ffd in DB::MergeTreeDataWriter::writeTempPart(DB::BlockWithPartition&, std::__1::shared_ptr<DB::StorageInMemoryMetadata const> const&, std::__1::shared_ptr<DB::Context const>) obj-x86_64-linux-gnu/../src/Storages/MergeTree/MergeTreeDataWriter.cpp:276:46
5 0x373c446c in DB::MergeTreeSink::consume(DB::Chunk) obj-x86_64-linux-gnu/../src/Storages/MergeTree/MergeTreeSink.cpp:27:65
Uninitialized value was created by a heap deallocation
6 0x32d481e8 in DB::DatabaseCatalog::TableMarkedAsDropped::~TableMarkedAsDropped() obj-x86_64-linux-gnu/../src/Interpreters/DatabaseCatalog.h:248:12
7 0x32d3c134 in DB::DatabaseCatalog::dropTableDataTask() obj-x86_64-linux-gnu/../src/Interpreters/DatabaseCatalog.cpp:908:1
[1]: https://s3.amazonaws.com/clickhouse-test-reports/32534/fa6090f588dbf4cbb5f28bd2210847b070bb8218/stress_test__memory__actions_.html
The query was CREATE MATERIALIZED VIEW ... POPULATE AS SELECT ... from
00040_aggregating_materialized_view test.
