Blocking granularity of gbase 8s concurrency control

         Blocking granularity Also become a lock Object or lock range , Indicates the scope of the blockade , for example , A lock on a record only applies to that record , A lock on a relationship applies to all records in that relationship .

         so , The amount of data involved in blocking is different with different blocking granularity .

         The higher the level of blocking objects , The larger the amount of data involved . The stronger the blockade , Such as blocking the whole database , All relationships in the database will be 、 The records are blocked , The ability of the system to handle a single transaction is stronger , The system overhead is relatively small , however , The concurrency of the system will be reduced , The ability to handle concurrent transactions will weaken .

         conversely , The smaller the blocking granularity , For example, block a single table or record , The concurrency of the system will be higher , The higher the system overhead .

        GBase 8s The lock mechanism can lock different Granularity objects , In a system, it is ideal to have blocking units of different sizes for different transactions at the same time .

         Comprehensive, , The higher the locking force, the lower the concurrency , such as An exclusive lock Lock database , Other users cannot connect to the database . conversely , If you monopolize a table A line Record , Then other users can access （ Read 、 modify ） Other records , therefore , Multi user system requirements High concurrency In the case of an interview , Try to use Low granularity locks , If Row-level locks , If the system requires less concurrency , Or do some administrative affairs （ Database Reconstruction 、 Table reconstruction ）, In order to obtain higher performance , High granularity locks can be used .