4 functions shall be implemented to view and clear table locks in ColumnStoreDriver

• listTableLocks() , returns all current table locks in an array of [lockId, sessionId, database, table]
• isTableLocked(std::string database, std::string table), returns true if the table is locked by another process and false if not
• clearTableLock(uint16_t id), clears a table lock with the specific lock Id and rolls back the killed transaction
• clearTableLock(std::string database, std::string table), clears a table lock for the specified database table combination and rolls back the killed transaction

Introducing 6 new functions to ColumnStoreDriver:

• std::vector listTableLocks();
• bool isTableLocked(const std::string & db, const std::string & table, TableLockInfo& rtn);
• bool isTableLocked(const std::string & db, const std::string & table);
• void clearTableLock(uint64_t lockId);
• void clearTableLock(const std::string & db, const std::string & table);
• void clearTableLock(TableLockInfo tbi);

Introducing a new datatype mcsapi::TableLockInfo to store table lock information.

mcsapi's introduced functions and data types ported to pymcsapi and javamcsapi

Introducing C++, Java, and Python tests for listTableLocks(), isTableLocked(), and clearTableLock()

Added new functions to documentation plus general documentation updates for javamcsapi and pymcsapi

Known limitations:

• mcsapi's isTableLocked() function is affected by MCOL-1218 and only detects locks of tables that were existent when the ColumnStoreDriver was initialized
• javamcsapi and pymcsapi don't yet have methods to access the dbroot array returned by TableLockInfo's getDbrootList()
• javamcsapi and pymcsapi don't yet have methods to access the the creation time returned by TableLockInfo's getCreationTime()
• pymcsapi's isTableLocked() function only returns bool but not also the additional TableLockInfo object mcsapi returns

Limitations addressed in MCOL-1961

For QA

• run regression test suite on CentOS 7, Windows 10, and one Debian/Ubuntu
• verify that the documentation is correct