Providing persistence for sensor data streams by remote WAL
DaWaK'06 Proceedings of the 8th international conference on Data Warehousing and Knowledge Discovery
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Sensor database systems need to provide both freshnessof data and persistence to the incoming sensor streams.Toprovide persistence,a disk based logging method has beenwidely used,however it is not applicable for sensor streamsbecause of its tardiness.In this paper,we ropose the LightNeighbor Write Ahead Logging protocol(L-WAL)for sensor streams.The L-WAL is a refinement of the Neighbor-WAL(N-WAL).The L-WAL needs two network interfacesand applies relaxed protocol than two phase commit protocol.Since the relaxed protocol weakens the guaranteeof logging successes,we have incorporated repair systemand checker system to enhance the guarantee.The resultof experiments shows that the L-WAL is about 2.13 timesfaster than the N-WAL when the number of concurrent sensor streams is 250 and the L-WAL can enhance the persistence of data almost for free,while the N-WAL needs to payhigh cost.