Lightweight Checkpointing for Faster SOAP Deserialization

Differential Deserialization (DDS) is an optimization technique that exploits similarities between incoming SOAP messages to reduce deserialization time. DDS works by checkpointing the state of the SOAP deserializer at various points while deserializing a message, and using those checkpoints to avoid full deserialization of similar messages. DDS can improve performance in many cases, but its benefit is limited by the potentially significant memory and processing overhead associated with its checkpointing mechanism. Differential checkpointing (DCP) substantially reduces memory use, but still requires significant processing overhead. In this paper, we introduce lightweight checkpointing (LCP), a checkpointing approach that significantly reduces the cost of both DDS and DCP, in terms of both memory use and processing time. LCP statically determines locations in the incoming message where it would be most efficient to create checkpoints. LCP creates checkpoints much faster than both our original DDS checkpointing mechanism and our DCP approach. LCP also has significantly smaller memory requirements. For example, in some of our test cases, LCP requires only 10% of the memory that DCP requires, and only 3% of the memory that our original approach required. In terms of processing time, deserialization with LCP is approximately 50% to 60% faster than without differential deserialization, when approximately half the message is unchanged from the previous message.