VIREL: Route-Local Lattice Residual Compression for Exact and Error-Bounded Floating-Point Time Series

Abstract

Floating-point page codecs exploit temporal smoothness, but existing methods keep prediction state in different representation domains: IEEE 754 words, erased IEEE 754 words, decimal fields, or integer surrogates. Which domain should carry temporal prediction state inside a database page remains an open question. We present VIREL, a page codec that predicts route-local lattice-coordinate residuals for values admitted to exact or error-bounded integer coordinates. Separate routes preserve the history of mixed source resolutions, and cost-based lattice-step normalization stores compact coordinates such as $z$ for $q=dz+r$ or $q/d$ for divisible error-lattice indices while restoring the same lattice point before reconstruction. On canonical exact streams with independent 1,024-value pages, VIREL-Exact-Fast reaches 6.0243$\times$ and VIREL-Exact-Upper reaches 7.0287$\times$, emitting 22.4% fewer bytes than the strongest evaluated exact baseline. On 74.70 million values in 48 streams, the two profiles reach 8.0629$\times$ and 9.6490$\times$. At $ε=10^{-3}$ on 15 Serf streams, VIREL-EB reaches 12.1094$\times$, emits 12.54% fewer bits than the strongest compliant error-bounded baseline, and preserves all pointwise bounds. Ablations show that integer-domain residual prediction and $q/d$ factoring reduce output by 53.05% and 18.75% in their respective settings. The Fast profile scales to 1,034/1,196 MB/s encode/decode at 64 cores. As an Apache TsFile codec, it writes 27.9-30.1% fewer complete-file bytes than DeXOR and ELF*, and with LZ4 reaches 105.80/102.32/110.30 MB/s on full-scan, range-scan, and aggregate queries, faster than the encoded baselines in all three read paths.