HPC applications generate massive amounts of data that impose significant burdens on both storage and I/O systems. Although lossy compressors have been widely adopted in this scenario to reduce data volume, the SOTA approach fails to fully exploit redundancy because it relies on separate techniques that operate at incompatible granularities. Their suboptimal compression ratios leave I/O as the dominant bottleneck in data dumps/loads. Therefore, we propose MAC, a compression framework built upon existing SZ compressor. It leverages the alignment between HPC system characteristics and modeling-based arithmetic coding to balance the compression ratio improvement and time cost. Instead of applying Huffman coding and dictionary-based compressors like zstd or gzip sequentially on quantization factors as SZ does, MAC replaces them with an adaptive arithmetic encoder. Specifically, MAC first employs bit-packing on incoming quantization factors to reduce overhead, as these factors are typically small enough that standard 4-byte storage would impede processing efficiency. The system then constructs context with the knowledge of the length of each quantization factor, utilizing hash tables to store and retrieve historical occurrences. By leveraging two models with distinct prefix-matching strategies and integrating them via a logistic mixer, MAC yields substantial compression gains. This architecture ensures that compression and decompression latencies remain low enough to accelerate overall dump and load operations. Experiments show that MACSZ achieves a compression ratio improvement of over 25%, which translates directly into enhanced throughput on HPC cluster architectures as Fig 1 and 2 demonstrate.

The explosive growth of global data has created an increasing demand for archival storage, where efficient compression is crucial to reduce capacity cost. However, existing archival compressors face a fundamental tradeoff: mainstream methods (e.g., ZSTD with level$21 / 22$) offer limited compression ratios, while context-mixing compressors (e.g., LPAQ) achieve higher ratios but are often too slow for practical use. Therefore, we present CuCM, a GPU-powered context-mixing compressor to overcome this tradeoff. By introducing pre-learning and batch update mechanisms, CuCM resolves the data dependencies inherent in the autoregressive modeling of contextmixing compressors. During compression, CuCM processes each predefined vector as a single unit. It utilizes the current model to predict the probability distribution for the entire vector, deferring model updates until the vector is fully processed. During decompression, CuCM employs an aggressive look-ahead strategy, preassuming bit values for context construction. It then retains only the outcomes of hypotheses that remain consistent with the actual decoded data. Experiments like figure 1 show that CuCM achieves up to$12.6 \times$higher throughput than LPAQ while maintaining comparable compression ratios across both general-purpose and archival datasets.

Current compressors for OLTP databases perform well on text but face challenges with integers, although integers are a critical component of the workload. Most existing integer compressors are ineffective as a complementary solution, since they compress integers together and cannot decompress a certain integer individually, making them incompatible with the data access requirement of OLTP databases. To this end, we propose Apic, a precomputation-based arithmetic coding to efficiently compress each integers (a very tiny unit), though small data are always hard to compress, and ensure compatibility with OLTP datasets. Specifically, Apic presents Bitwidth-aware Precomputed Frequency and Prefixaware Precomputed Decoding to tackle challenges of applying arithmetic coding in this scenario, such as the substantial space costs of symbol frequencies and decompression complexity. Evaluations on real-world and desensitized commercial datasets suggest that Apic improves the compression ratio by up to 80% on integers over VByte, while preserving comparable decompression speed and thus query performance.

The row-oriented store model is the cornerstone component of modern online transaction processing (OLTP) database systems. In response to the massive increase in data within database systems, compression techniques are employed to enhance storage efficiency. Regrettably, current compression methods suffer from either the amplification issue due to coarse compression granularity or inefficient decompression operations, thus usually decreasing the speed of query processing. To this end, we present DPTC, a cost-effective and decompression-transparent approach designed to compress data pages, the basic storage unit of OLTP database systems. Specifically, (1) DPTC applies a row-wise decompression-oriented structure to track the first occurrence of redundant data in compressed data, which effectively supports the decompression of individual records from pages, thereby avoiding unwarranted decompression in record access. Moreover, (2) DPTC employs an in-page dynamic packing strategy, which determines the compression units based on the impact of each data reduction operation on the compression gains and eliminates gains-inefficient data reductions. Furthermore, (3) DPTC utilizes a SIMD-based mechanism that leverages the characteristics of operations within the decompression process to improve the decompression speed. Our evaluation results confirm that DPTC is efficient in terms of decompression speed and compression ratio. Within an OLTP database system, DPTC yields throughput improvements of up to 4.28 x in TPC-C and reduces latency by up to 33.3% for data point queries in a row-oriented storage engine.

In recent years, the performance of hash indexes has been significantly improved by exploiting emerging persistent memory (PMem). However, the performance improvement of hash indexes mainly comes from exploiting the hardware features of PMem. Only a few studies optimize the hash index itself to fully exploit the potential of PMem. Interestingly, many of these studies improve the performance of write, but disregard the performance of read, of hash indexes on PMem. With extensive experimental evaluation, we find the major reason for inefficient read in the hash index on PMem is that the overhead of hash collision processing is expensive.To address that, we propose a novel Efficient Extendible Perfect Hashing (EEPH) on PMem-DRAM hybrid data layout to improve read performance of hash indexes. Specifically, we reduce the overhead of dynamic perfect hashing extension on PMem by combing extendible hashing. We then design a hybrid data layout to unlock the inherent read strengths of perfect hashing (i.e., zero collision). Last, we devise a complement move algorithm to efficiently guarantee the zero collision of perfect hashing when data move is conducted on PMem. We compare EEPH with the state-of-the-art hash indexes on PMem by conducting comprehensive experiments on several real-world read-intensive and read-skew workloads. The experimental results confirm the superiority of our EEPH as it achieves up to 2.21× higher throughput and about 1/3 of the 99th percentile latency than state-of-the-art hash indexes.