Sergei Petrunia added a comment - 2018-12-02 21:21 One of the reasons: information_schema.rocksdb_trx and information_schema.rocksdb_deadlock tables. These expose information about current transactions and last N deadlocks, respectively. The information is not present in range locking mode. The first thing that is not present (and causes rocksdb.i_s_deadlock to fail) is information_schema.rocksdb_trx.WAITING_KEY field.

Sergei Petrunia added a comment - 2018-12-02 21:24 Regular lock manager (TransactionLockMgr) "notifies" transactions about other transactions that are waiting for it (see stack trace below). This happens even when deadlock detection is OFF. (gdb) wher #0 rocksdb::PessimisticTransaction::SetWaitingTxn (this=0x7fffd800aa20, ids=..., column_family_id=0, key=0x7ffff42d04a0) at /home/psergey/dev-git/mysql-5.6-rangelocking2-rebase1/rocksdb/utilities/transactions/pessimistic_transaction.h:80 #1 0x0000555556f6e732 in rocksdb::TransactionLockMgr::AcquireWithTimeout (this=0x555558200670, txn=0x7fffd800aa20, lock_map=0x5555581d3f40, stripe=0x5555581d6d10, column_family_id=0, key="\000\000\001\004\200\000\000\001", env=0x555557e77360 <rocksdb::Env::Default()::default_env>, timeout=10000000000, lock_info=...) at /home/psergey/dev-git/mysql-5.6-rangelocking2-rebase1/rocksdb/utilities/transactions/transaction_lock_mgr.cc:442 #2 0x0000555556f6de94 in rocksdb::TransactionLockMgr::TryLock (this=0x555558200670, txn=0x7fffd800aa20, column_family_id=0, key="\000\000\001\004\200\000\000\001", env=0x555557e77360 <rocksdb::Env::Default()::default_env>, exclusive=true) at /home/psergey/dev-git/mysql-5.6-rangelocking2-rebase1/rocksdb/utilities/transactions/transaction_lock_mgr.cc:315 #3 0x0000555556f5c741 in rocksdb::PessimisticTransactionDB::TryLock (this=0x5555582005f0, txn=0x7fffd800aa20, cfh_id=0, key="\000\000\001\004\200\000\000\001", exclusive=true) at /home/psergey/dev-git/mysql-5.6-rangelocking2-rebase1/rocksdb/utilities/transactions/pessimistic_transaction_db.cc:389 #4 0x000055555706c253 in rocksdb::PessimisticTransaction::TryLock (this=0x7fffd800aa20, column_family=0x5555581d3280, key=..., read_only=true, exclusive=true, skip_validate=false) at /home/psergey/dev-git/mysql-5.6-rangelocking2-rebase1/rocksdb/utilities/transactions/pessimistic_transaction.cc:529 #5 0x0000555557075644 in rocksdb::TransactionBaseImpl::GetForUpdate (this=0x7fffd800aa20, read_options=..., column_family=0x5555581d3280, key=..., pinnable_val=0x7fffd800e838, exclusive=true) at /home/psergey/dev-git/mysql-5.6-rangelocking2-rebase1/rocksdb/utilities/transactions/transaction_base.cc:238 #6 0x0000555556b3edb4 in myrocks::Rdb_transaction_impl::get_for_update (this=0x7fffd800a810, column_family=0x5555581d3280, key=..., value=0x7fffd800e838, exclusive=true) at /home/psergey/dev-git/mysql-5.6-rangelocking2-rebase1/storage/rocksdb/ha_rocksdb.cc:2942 #7 0x0000555556b1b907 in myrocks::ha_rocksdb::get_for_update (this=0x7fffd800e300, tx=0x7fffd800a810, column_family=0x5555581d3280, key=..., value=0x7fffd800e838) at /home/psergey/dev-git/mysql-5.6-rangelocking2-rebase1/storage/rocksdb/ha_rocksdb.cc:8659 #8 0x0000555556b1bee7 in myrocks::ha_rocksdb::get_row_by_rowid (this=0x7fffd800e300, buf=0x7fffd800baf0 "\320\001", rowid=0x7fffd800ddc0 "", rowid_size=8, skip_lookup=false, skip_ttl_check=false) at /home/psergey/dev-git/mysql-5.6-rangelocking2-rebase1/storage/rocksdb/ha_rocksdb.cc:8733 #9 0x0000555556b384a7 in myrocks::ha_rocksdb::get_row_by_rowid (this=0x7fffd800e300, buf=0x7fffd800baf0 "\320\001", rowid=0x7fffd800ddc0 "", rowid_size=8, skip_lookup=false, skip_ttl_check=false) at /home/psergey/dev-git/mysql-5.6-rangelocking2-rebase1/storage/rocksdb/./ha_rocksdb.h:685 #10 0x0000555556b1a0eb in myrocks::ha_rocksdb::index_read_map_impl (this=0x7fffd800e300, buf=0x7fffd800baf0 "\320\001", key=0x7fffd80078a8 "\001", keypart_map=1, find_flag=HA_READ_KEY_EXACT, end_key=0x0) at /home/psergey/dev-git/mysql-5.6-rangelocking2-rebase1/storage/rocksdb/ha_rocksdb.cc:8227

Sergei Petrunia added a comment - 2018-12-02 21:36 OK, lock wait should call these methods in rocksdb::PessimisticTransaction void SetWaitingTxn(autovector<TransactionID> ids, uint32_t column_family_id, const std::string* key) ; void ClearWaitingTxn() ;