Similarity searching is a useful operation for many real applications that work on non-structured or multimedia databases. In these scenarios, it is significant to search similar objects to another object given as a query. There exist several indexes to avoid exhaustively review all database objects to answer a query. In many cases, even with the help of an index, it could not be enough to have reasonable response times, and it is necessary to consider approximate similarity searches. In this kind of similarity search, accuracy or determinism is traded for faster searches. A good representative for approximate similarity searches is the Permutation Index.
In this paper, we give an implementation of the Permutation Index on GPU to speed approximate similarity search on massive databases. Our implementation takes advantage of the GPU parallelism. Besides, we consider speeding up the answer time of several queries at the same time.
We also evaluate our parallel index considering answer quality and time performance on the different GPUs. The search performance is promising, independently of their architecture, because of careful planning and the correct resources use.