TY - GEN
T1 - GriDB: Scaling Blockchain Database via Sharding and Off-Chain Cross-Shard Mechanism
AU - Hong, Zicong
AU - Guo, Song
AU - Zhou, Enyuan
AU - Chen, Wuhui
AU - Huang, Huawei
AU - Zomaya, Albert
N1 - Funding Information:
This research was supported by fundings from the Key-Area Research and Development Program of Guangdong Province under grant No. 2021B0101400003, Hong Kong RGC Research Impact Fund (RIF) with the Project No. R5060-19, General Research Fund (GRF) with the Project No. 152221/19E, 152203/20E, 152244/21E, and 152169/22E, and the National Natural Science Foundation of China (NSFC) 61872310, 62172453 and 62272496, Shenzhen Science and Technology Innovation Commission ( JCYJ20200109142008673), the Major Key Project of PCL (PCL2021A06), and the Pearl River Talent Recruitment Program (2019QN01X130). We thank all anonymous reviewers who helped improve the paper.
Publisher Copyright:
© 2023, VLDB Endowment. All rights reserved.
PY - 2023/3
Y1 - 2023/3
N2 - Blockchain databases have attracted widespread attention but suffer from poor scalability due to underlying non-scalable blockchains. While blockchain sharding is necessary for a scalable blockchain database, it poses a new challenge named on-chain cross-shard database services. Each cross-shard database service (e.g., cross-shard queries or inter-shard load balancing) involves massive cross-shard data exchanges, while the existing cross-shard mechanisms need to process each cross-shard data exchange via the consensus of all nodes in the related shards (i.e., on-chain) to resist a Byzantine environment of blockchain, which eliminates sharding benefits. To tackle the challenge, this paper presents GriDB, the first scalable blockchain database, by designing a novel off-chain cross-shard mechanism for efficient cross-shard database services. Borrowing the idea of off-chain payments, GriDB delegates massive cross-shard data exchange to a few nodes, each of which is randomly picked from a different shard. Considering the Byzantine environment, the untrusted delegates cooperate to generate succinct proof for cross-shard data exchanges, while the consensus is only responsible for the low-cost proof verification. However, different from payments, the database services’ verification has more requirements (e.g., completeness, correctness, freshness, and availability); thus, we introduce several new authenticated data structures (ADS). Particularly, we utilize consensus to extend the threat model and reduce the complexity of traditional accumulator-based ADS for verifiable cross-shard queries with a rich set of relational operators. Moreover, we study the necessity of inter-shard load balancing for a scalable blockchain database and design an off-chain and live approach for both efficiency and availability during balancing. An evaluation of our prototype shows the performance of GriDB in terms of scalability in workloads with queries and updates.
AB - Blockchain databases have attracted widespread attention but suffer from poor scalability due to underlying non-scalable blockchains. While blockchain sharding is necessary for a scalable blockchain database, it poses a new challenge named on-chain cross-shard database services. Each cross-shard database service (e.g., cross-shard queries or inter-shard load balancing) involves massive cross-shard data exchanges, while the existing cross-shard mechanisms need to process each cross-shard data exchange via the consensus of all nodes in the related shards (i.e., on-chain) to resist a Byzantine environment of blockchain, which eliminates sharding benefits. To tackle the challenge, this paper presents GriDB, the first scalable blockchain database, by designing a novel off-chain cross-shard mechanism for efficient cross-shard database services. Borrowing the idea of off-chain payments, GriDB delegates massive cross-shard data exchange to a few nodes, each of which is randomly picked from a different shard. Considering the Byzantine environment, the untrusted delegates cooperate to generate succinct proof for cross-shard data exchanges, while the consensus is only responsible for the low-cost proof verification. However, different from payments, the database services’ verification has more requirements (e.g., completeness, correctness, freshness, and availability); thus, we introduce several new authenticated data structures (ADS). Particularly, we utilize consensus to extend the threat model and reduce the complexity of traditional accumulator-based ADS for verifiable cross-shard queries with a rich set of relational operators. Moreover, we study the necessity of inter-shard load balancing for a scalable blockchain database and design an off-chain and live approach for both efficiency and availability during balancing. An evaluation of our prototype shows the performance of GriDB in terms of scalability in workloads with queries and updates.
UR - http://www.scopus.com/inward/record.url?scp=85159490087&partnerID=8YFLogxK
U2 - 10.14778/3587136.3587143
DO - 10.14778/3587136.3587143
M3 - Conference article published in proceeding or book
AN - SCOPUS:85159490087
VL - 16
T3 - Proceedings of the VLDB Endowment
SP - 1685
EP - 1698
BT - Proceedings of the VLDB Endowment
T2 - 49th International Conference on Very Large Data Bases, VLDB 2023
Y2 - 28 August 2023 through 1 September 2023
ER -