Blockchain systems such as Hyperledger Fabric that adopts the execute-order-validate(EOV)transaction model usually use the multi-version concurrency control(MVCC)method to validate transactions.The basic idea is to check whether the read set of the current transaction has been modified by cross-block and intra-block transac-tions before committing,to ensure transaction isolation and correctness.However,MVCC often becomes the per-formance bottleneck of the entire transaction due to low parallelization and frequent access to the underlying data-base system.To solve this problem,this paper proposes two new MVCC algorithms:C-MVCC and P-MVCC.C-MVCC uses memory as a cache to reduce access to the underlying database system during MVCC validation,and introduces a parallelization mechanism for the cross-shard validation stage.P-MVCC further decomposes the de-pendency relationship between transactions based on C-MVCC,and realizes parallelization of cross-block and intra-block validation,thus eliminating the accumulation of high cross-shard validation latency in sharding scenarios.Ex-perimental results show that C-MVCC can bring 7.5 times improvement in validation efficiency compared with the current algorithm in general scenarios,while P-MVCC can bring 9.0 times improvement in validation efficiency in sharding scenarios.
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