With Processors max_distributed_connections does not used anymore, since
it always uses not more then max_threads (see
TCPHandler::processOrdinaryQueryWithProcessors()/
QueryPipeline::execute()/PipelineExecutor::execute())
So just use QueryPipeline::getNumThreads(), that takes
max_distributed_connections into account.
Otherwise you will get non completed progress on TCP, HTTP does not
affected.
Final updateProgress called from the executeQueryImpl::finish_callback:
(gdb) bt
0 DB::TCPHandler::updateProgress (this=0x7fffb581e000, value=...) at TCPHandler.cpp:1178
1 0x00007ffff7c62038 in DB::TCPHandler::<lambda(const DB::Progress&)>::operator()(const DB::Progress &) const (...) at TCPHandler.cpp:127
4 0x00007fffe9a86671 in DB::<lambda(DB::IBlockInputStream*, DB::IBlockOutputStream*)>::operator()(DB::IBlockInputStream *, DB::IBlockOutputStream *) (__closure=0x7fffb588f300,
stream_in=0x7fffb5800290, stream_out=0x0) at executeQuery.cpp:450
5 0x00007fffe9a8b948 in std::_Function_handler<void(DB::IBlockInputStream*, DB::IBlockOutputStream*), DB::executeQueryImpl(...)::<lambda(DB::IBlockInputStream*, DB::IBlockOutputStream*)> >::_M_invoke(const std::_Any_data &, DB::IBlockInputStream *&&, DB::IBlockOutputStream *&&) (...) at std_function.h:300
6 0x00007ffff7c7482f in std::function<>::operator()(DB::IBlockInputStream*, DB::IBlockOutputStream*) const (..) at std_function.h:688
7 0x00007ffff7c6f82b in DB::BlockIO::onFinish (this=0x7fffb5820738) at BlockIO.h:43
8 0x00007ffff7c65eb0 in DB::TCPHandler::processOrdinaryQuery (this=0x7fffb581e000) at TCPHandler.cpp:540
9 0x00007ffff7c63a50 in DB::TCPHandler::runImpl (this=0x7fffb581e000) at TCPHandler.cpp:269
10 0x00007ffff7c6a6fd in DB::TCPHandler::run (this=0x7fffb581e000) at TCPHandler.cpp:1226
...
Before this patch if the query failes (due to "Too many simultaneous
queries" for example) it will not read external tables info, and the
next request will interpret them as the query beginning at got:
DB::Exception: Unknown packet 11861 from client
v2: reordering in the executeQuery() is not enough, since the query
can fail in other places, before, i.e. quotas
v3: I cannot make non-intergration test (since there is no ability to
receive "Unknown packet" via client, only from the server log),
hence added one
