Direct Transformation Techniques for Compressed Data: General Approach and Application Scenarios
Direct Transformation Techniques for Compressed Data: General Approach and Application Scenarios
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压缩数据的直接转换技术：通用方法和应用场景
DOI：
10.1007/978-3-319-23135-8_11
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
Wolfgang Lehner
中科院分区：
文献类型：
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作者：
Patrick Damme;Dirk Habich;Wolfgang Lehner
轻量级数据压缩技术，如字典压缩或游程压缩，在主存数据库系统中起着重要的作用。在为数据集决定了压缩方案之后，到另一个方案的转换在今天是非常低效的。常见的方法工作如下：首先，使用源解压缩算法对压缩数据进行解压缩，从而在主存储器中物化原始数据。其次，应用目标方案的压缩算法。这种间接的方法依赖于现有的算法，但效率非常低，因为整个未压缩的数据必须作为中间步骤被具体化。为了克服这些缺点，我们提出了一种新的方法称为直接变换，它避免了整个未压缩数据的物化。我们的技术是缓存优化，以减少必要的数据访问。此外，我们提出的应用场景，这样的直接转换可以有效地应用。
Lightweight data compression techniques like dictionary or run-length compression play an important role in main memory database systems. Having decided for a compression scheme for a dataset, the transformation to another scheme is very inefficient today. The common approach works as follows: First, the compressed data is decompressed using the source decompression algorithm resulting in the materialization of the raw data in main memory. Second, the compression algorithm of the destination scheme is applied. This indirect way relies on existing algorithms, but is very inefficient, since the whole uncompressed data has to be materialized as an intermediate step. To overcome these drawbacks, we propose a novel approach calleddirect transformation, which avoids the materialization of the whole uncompressed data. Our techniques are cache optimized to reduce necessary data accesses. Moreover, we present application scenarios, where such direct transformations can be efficiently applied.
使用 SIMD 指令进行快速整数压缩
DOI：
10.1145/1869389.1869394
发表时间：
2010
期刊：
[1990] Proceedings. The 17th Annual International Symposium on Computer Architecture
影响因子：
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作者：
B. Schlegel;Rainer Gemulla;Wolfgang Lehner
通讯作者：
Wolfgang Lehner