An analysis of LSM caching in NVRAM

Lersch, Lucas; Oukid, Ismail; Lehner, Wolfgang; Schreter, Ivan

doi:10.1145/3076113.3076123

Cited by 8 publications

(3 citation statements)

References 3 publications

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“…Their main consensus is to leave nodes unsorted and generally reduce writes. There is also some work on radix trees [19], LSM-Trees [18,21] and hash maps [26,31]. To the best of our knowledge, so far, only [8] considers a multi-dimensional layout and analytical queries.…”

Section: Related Workmentioning

confidence: 99%

“…Replacement strategies for dynamic caching. Regarding the replacement strategy, Lersch et al [21] already investigated the application of a dynamic cache with eviction policy in the context of LSM-Trees on PMem. As these have shown possible benefits for a read-only setup, we envisage to re-use the tested LRU (least recently used) and the more optimized 2Q policies in our analytical context.…”

Section: Selective Cachingmentioning

confidence: 99%

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Selective caching: a persistent memory approach for multi-dimensional index structures

Jibril

Götze

Broneske

et al. 2021

Distrib Parallel Databases

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After the introduction of Persistent Memory in the form of Intel’s Optane DC Persistent Memory on the market in 2019, it has found its way into manifold applications and systems. As Google and other cloud infrastructure providers are starting to incorporate Persistent Memory into their portfolio, it is only logical that cloud applications have to exploit its inherent properties. Persistent Memory can serve as a DRAM substitute, but guarantees persistence at the cost of compromised read/write performance compared to standard DRAM. These properties particularly affect the performance of index structures, since they are subject to frequent updates and queries. However, adapting each and every index structure to exploit the properties of Persistent Memory is tedious. Hence, we require a general technique that hides this access gap, e.g., by using DRAM caching strategies. To exploit Persistent Memory properties for analytical index structures, we propose selective caching. It is based on a mixture of dynamic and static caching of tree nodes in DRAM to reach near-DRAM access speeds for index structures. In this paper, we evaluate selective caching on the OLAP-optimized main-memory index structure Elf, because its memory layout allows for an easy caching. Our experiments show that if configured well, selective caching with a suitable replacement strategy can keep pace with pure DRAM storage of Elf while guaranteeing persistence. These results are also reflected when selective caching is used for parallel workloads.

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Section: Related Workmentioning

confidence: 99%

Section: Selective Cachingmentioning

confidence: 99%

Selective caching: a persistent memory approach for multi-dimensional index structures

Jibril

Götze

Broneske

et al. 2021

Distrib Parallel Databases

View full text Add to dashboard Cite

show abstract

“…Many modern keyvalue stores such as RocksDB [6] or Cassandra [27] are based on this concept. There are already first approaches to adapt this concept for PM [15,20,21]. Furthermore, prefix trees (tries) like ART were already migrated to PM [7] as well as some write optimized versions of it [18].…”

Section: Related Workmentioning

confidence: 99%

Data Structure Primitives on Persistent Memory: An Evaluation

Götze¹,

Tharanatha²,

Sattler³

2020

Preprint

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Persistent Memory (PM), as already available e.g. with Intel Optane DC Persistent Memory, represents a very promising, next generation memory solution with a significant impact on database architectures. Several data structures for this new technology and its properties have already been proposed. However, primarily merely complete structures were presented and evaluated hiding the impact of the individual ideas and PM characteristics. Therefore, in this paper, we disassemble the structures presented so far, identify their underlying design primitives, and assign them to appropriate design goals regarding PM. As a result of our comprehensive experiments on real PM hardware, we were able to reveal the trade-offs of the primitives at the micro level. From this, performance profiles could be derived for selected primitives. With these it is possible to precisely identify their best use cases as well as vulnerabilities. Beside our general insights regarding PM-based data structure design, we also discovered new promising combinations not considered in the literature so far.

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Selective Caching: A Persistent Memory Approach for Multi-Dimensional Index Structures

Jibril

Götze

Broneske

et al. 2020

2020 IEEE 36th International Conference on Data Engineering Workshops (ICDEW)

View full text Add to dashboard Cite

After the introduction of Persistent Memory in the form of Intel's Optane DC Persistent Memory on the market in 2019, it has found its way into manifold applications and systems. As Google and other cloud infrastructure providers are starting to incorporate Persistent Memory into their portfolio, it is only logical that cloud applications have to exploit its inherent properties. Persistent Memory can serve as a DRAM substitute, but guarantees persistence at the cost of compromised read/write performance compared to standard DRAM. These properties particularly affect the performance of index structures, since they are subject to frequent updates and queries. However, adapting each and every index structure to exploit the properties of Persistent Memory is tedious. Hence, we require a general technique that hides this access gap, e.g., by using DRAM caching strategies. To exploit Persistent Memory properties for analytical index structures, we propose selective caching. It is based on a mixture of dynamic and static caching of tree nodes in DRAM to reach near-DRAM access speeds for index structures. In this paper, we evaluate selective caching on the OLAP-optimized main-memory index structure Elf, because its memory layout allows for an easy caching. Our experiments show that if configured well, selective caching with a suitable replacement strategy can keep pace with pure DRAM storage of Elf while guaranteeing persistence. These results are also reflected when selective caching is used for parallel workloads.

show abstract

An analysis of LSM caching in NVRAM

Cited by 8 publications

References 3 publications

Selective caching: a persistent memory approach for multi-dimensional index structures

Selective caching: a persistent memory approach for multi-dimensional index structures

Data Structure Primitives on Persistent Memory: An Evaluation

Selective Caching: A Persistent Memory Approach for Multi-Dimensional Index Structures

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