3441426 - All statements wait for NameserverLock_WriteLock, CPU usage is high

• HANA DB high CPU usage
• Many threads wait for NameserverLock_WriteLock lock
• Most Threads has the following call stack:
   0: 0x00007ff1eb5f47c9 in syscall+0x17 (libc.so.6)
     1: 0x00007ff1ec5cbc52 in Synchronization::Mutex::lockInternal(Execution::Context&, unsigned long, unsigned long, bool)+0x1f0 at Basis/Synchronization/impl/LinuxFutexOps.hpp:46 (libhdbbasis.so)
     2: 0x00007ff1f0766242 in TrexIpc::NameserverLock::acquireRead()+0x70 at Basis/Synchronization/LockedScope.hpp:57 (libhdbbasement.so)
     3: 0x00007ff219dd4f30 in NameServer::FTreeContainer::queryTree(NameServer::TNode const&, NameServer::TNode&, NameServer::QueryMode)+0x4a0 at TREXNameServer/FTreeContainer.h:38 (libhdbns.so)
     4: 0x00007ff219f3fa72 in NameServer::NameServerProxy::queryTree(NameServer::TNode const&, NameServer::TNode&, NameServer::QueryMode, TREX_ERROR::TRexError&)+0x50 at TREXNameServer/NameServerProxy.cpp:284 (libhdbns.so)
     5: 0x00007ff1f0900336 in NameServer::TNSClient::queryTree(NameServer::TNode const&, NameServer::TNode&, NameServer::QueryMode)+0x92 at TREXNameServer/TNSClient.cpp:581 (libhdbbasement.so)
     6: 0x00007ff1f0917a6f in NameServer::TNSClient::getCatalogServiceVolume(NameServer::ServiceType, ltt::basic_string<char, ltt::char_traits<char>, ltt::integral_constant<int, 64> > const&, ltt::basic_string<char, ltt::char_traits<char>, ltt::integral_constant<int, 64> >&)+0x4ab at TREXNameServer/TNSClient.cpp:3492 (libhdbbasement.so)
     7: 0x00007ff1f091df31 in NameServer::TNSClient::getServers_(bool, unsigned int, ltt::set<NameServer::ServiceType, ltt::less<NameServer::ServiceType>, ltt::rb_tree_balancier> const&, NameServer::Active, ltt_adp::vector<NameServer::ServerInfo, ltt::integral_constant<bool, true> >&)+0x4e0 at TREXNameServer/TNSClient.cpp:3542 (libhdbbasement.so)
     8: 0x00007ff1f0920e64 in NameServer::TNSClient::getServers(unsigned int, NameServer::ServiceType, NameServer::Active, ltt_adp::vector<NameServer::ServerInfo, ltt::integral_constant<bool, true> >&)+0x110 at TREXNameServer/TNSClient.cpp:3465 (libhdbbasement.so)
     9: 0x00007ff211b5f453 in ptime::Query::check_routing_condition_for_replication(ptime::Transaction&, ptime::Query::Plan*)+0xb0 at ptime/query/query_replication.cc:110 (libhdbrskernel.so)
    10: 0x00007ff208141edf in ptime::CommonApiImpl::probe_related_objects(ptime::Transaction&, ptime::Query::Plan*, SQL::Optimizer::Context&) const+0x6b at ptime/query/plan_generator/dml_search/api/impl/CommonApiImpl.cpp:704 (libhdbsqloptimizer.so)
    11: 0x00007ff211b256f7 in ptime::Query::compile_parse_tree(ltt::smartptr_handle<SQL::Optimizer::CommonApi>, char const*, bool, char const*, char const*, void*, ptime::Query::PlanHandle&, ptime::Query::PlanVizQueryFlag&, ptime::Query::PlanCache::EntryHandle&, bool, ptime::IdTable*, bool, bool, bool, ptime::Query::CompilationPurpose, bool, bool, bool, bool, SQL::Optimizer::RelTree**, ptime::Query::PlanCache::Key*, long, char const*)+0x5ab3 at ptime/query/query.cc:2785 (libhdbrskernel.so)

HANA 1.0

HANA 2.0

KBA , HAN-DB-PERF , SAP HANA Database Performance , Problem