TY - CHAP A1 - Gottstein, Robert A1 - Goyal, Rohit A1 - Hardock, Sergej A1 - Petrov, Ilia A1 - Buchmann, Alejandro T1 - MV-IDX : indexing in multi-version databases T2 - Proceedings of the 18th International Database Engineering & Applications Symposium : IDEAS '14 : Instituto Superior de Engenharia do Porto : Porto, Portugal, July 7-9, 2014 N2 - An index in a Multi-Version DBMS (MV-DBMS) has to reflect different tuple versions of a single data item. Existing approaches follow the paradigm of logically separating the tuple version data from the data item, e.g. an index is only allowed to return at most one version of a single data item (while it may return multiple data items that match a search criteria). Hence to determine the valid (and therefore visible) tuple version of a data item, the MV-DBMS first fetches all tuple versions that match the search criteria and subsequently filters visible versions using visibility checks. This involves I/O storage accesses to tuple versions that do not have to be fetched. In this vision paper we present the Multi Version Index (MV-IDX) approach that allows index-only visibility checks which significantly reduce the amount of I/O storage accesses as well as the index maintenance overhead. The MV-IDX achieves significantly lower response times and higher transactional throughput on OLTP workloads. Y1 - 2014 SN - 978-1-4503-2627-8 U6 - http://dx.doi.org/10.1145/2628194.2628911 VL - 2014 IS - 7 SP - 142 EP - 148 PB - ACM CY - New York ER - TY - CHAP A1 - Petrov, Ilia A1 - Gottstein, Robert A1 - Hardock, Sergej T1 - DBMS on modern storage hardware T2 - IEEE 31st International Conference on Data Engineering (ICDE), 2015 ; 13. - 17. April 2015, Seoul, Korea N2 - In the present tutorial we perform a cross-cut analysis of database systems from the perspective of modern storage technology, namely Flash memory. We argue that neither the design of modern DBMS, nor the architecture of flash storage technologies are aligned with each other. The result is needlessly suboptimal DBMS performance and inefficient flash utilisation as well as low flash storage endurance and reliability. We showcase new DBMS approaches with improved algorithms and leaner architectures, designed to leverage the properties of modern storage technologies. We cover the area of transaction management and multi-versioning, putting a special emphasis on: (i) version organisation models and invalidation mechanisms in multi-versioning DBMS; (ii) Flash storage management especially on append-based storage in tuple granularity; (iii) Flash-friendly buffer management; as well as (iv) improvements in the searching and indexing models. Furthermore, we present our NoFTL approach to native Flash access that integrates parts of the flash-management functionality into the DBMS yielding significant performance increase and simplification of the I/O stack. In addition, we cover the basics of building large Flash storage for DBMS and revisit some of the RAID techniques and principles. Y1 - 2015 SN - 978-1-4799-7964-6 U6 - http://dx.doi.org/10.1109/ICDE.2015.7113423 SP - 1545 EP - 1548 PB - IEEE CY - Piscataway, NJ ER - TY - CHAP A1 - Hardock, Sergej A1 - Petrov, Ilia A1 - Gottstein, Robert A1 - Buchmann, Alejandro ED - Gustavo, Alonso T1 - NoFTL for real : databases on real native Flash storage T2 - Advances in database technology - EDBT 2015 : 18th International Conference on Extending Database Technology, Brussels, Belgium, March 23 - 27, 2015 : proceedings N2 - Flash SSDs are omnipresent as database storage. HDD replacement is seamless since Flash SSDs implement the same legacy hardware and software interfaces to enable backward compatibility. Yet, the price paid is high as backward compatibility masks the native behaviour, incurs significant complexity and decreases I/O performance, making it non-robust and unpredictable. Flash SSDs are black-boxes. Although DBMS have ample mechanisms to control hardware directly and utilize the performance potential of Flash memory, the legacy interfaces and black-box architecture of Flash devices prevent them from doing so. In this paper we demonstrate NoFTL, an approach that enables native Flash access and integrates parts of the Flashmanagement functionality into the DBMS yielding significant performance increase and simplification of the I/O stack. NoFTL is implemented on real hardware based on the OpenSSD research platform. The contributions of this paper include: (i) a description of the NoFTL native Flash storage architecture; (ii) its integration in Shore-MT and (iii) performance evaluation of NoFTL on a real Flash SSD and on an on-line data-driven Flash emulator under TPCB, C,E and H workloads. The performance evaluation results indicate an improvement of at least 2.4x on real hardware over conventional Flash storage; as well as better utilisation of native Flash parallelism. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bsz:rt2-opus4-8066 UR - http://openproceedings.org./html/pages/2015_edbt.html SN - 978-3-89318-067-7 SP - 517 EP - 520 PB - University of Konstanz, University Library CY - Konstanz ER - TY - CHAP A1 - Gottstein, Robert A1 - Petrov, Ilia A1 - Buchmann, Alejandro A1 - Hardock, Sergej ED - Bordawekar, Rajesh T1 - SIASChains: Snapshot Isolation Append Storage Chains T2 - International Workshop on Accelerating Analytics and Data Management Systems Using Modern Processor and Storage Architectures, ADMS@VLDB 2017, Munich, Germany, September 1, 2017 N2 - Asymmetric read/write storage technologies such as Flash are becoming a dominant trend in modern database systems. They introduce hardware characteristics and properties which are fundamentally different from those of traditional storage technologies such as HDDs. Multi-Versioning Database Management Systems (MV-DBMSs) and Log-based Storage Managers (LbSMs) are concepts that can effectively address the properties of these storage technologies but are designed for the characteristics of legacy hardware. A critical component of MV-DBMSs is the invalidation model: commonly, transactional timestamps are assigned to the old and the new version, resulting in two independent (physical) update operations. Those entail multiple random writes as well as in-place updates, sub-optimal for new storage technologies both in terms of performance and endurance. Traditional page-append LbSM approaches alleviate random writes and immediate in-place updates, hence reducing the negative impact of Flash read/write asymmetry. Nevertheless, they entail significant mapping overhead, leading to write amplification. In this work we present an approach called Snapshot Isolation Append Storage Chains (SIAS-Chains) that employs a combination of multi-versioning, append storage management in tuple granularity and novel singly-linked (chain-like) version organization. SIAS-Chains features: simplified buffer management, multi-version indexing and introduces read/write optimizations to data placement on modern storage media. SIAS-Chains algorithmically avoids small in-place updates, caused by in-place invalidation and converts them into appends. Every modification operation is executed as an append and recently inserted tuple versions are co-located. Y1 - 2017 UR - https://dblp.org/rec/conf/vldb/GottsteinPHB17 SP - 50 EP - 57 PB - Universität Trier CY - Trier ER - TY - CHAP A1 - Hardock, Sergej A1 - Petrov, Ilia A1 - Buchmann, Alejandro A1 - Gottstein, Robert ED - Pitoura, Evaggelia T1 - Revisiting DBMS space management for native Flash T2 - Advances in database technology : EDBT 2016 ; 19th International Conference on Extending Database Technology, Bordeaux, France, March 15 - 18, 2016, proceedings N2 - In this paper we present our work in progress on revisiting traditional DBMS mechanisms to manage space on native Flash and how it is administered by the DBA. Our observations and initial results show that: the standard logical database structures can be used for physical organization of data on native Flash; at the same time higher DBMS performance is achieved without incurring extra DBA overhead. Initial experimental evaluation indicates a 20% increase in transactional throughput under TPC-C, by performing intelligent data placement on Flash, less erase operations and thus better Flash longevity. Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bsz:rt2-opus4-9535 UR - http://openproceedings.org/html/pages/2016_edbt.html SN - 978-3-89318-070-7 SP - 694 EP - 695 PB - OpenProceedings CY - Konstanz ER - TY - CHAP A1 - Hardock, Sergej A1 - Petrov, Ilia A1 - Gottstein, Robert A1 - Buchmann, Alejandro ED - Mitschang, Bernhard T1 - Effective DMBS space management on native Flash T2 - Datenbanksysteme für Business, Technologie und Web : BTW 2017. - (GI-Edition : Proceedings. - 265) N2 - In this paper we build on our research in data management on native Flash storage. In particular we demonstrate the advantages of intelligent data placement strategies. To effectively manage phsical Flash space and organize the data on it, we utilize novel storage structures such as regions and groups. These are coupled to common DBMS logical structures, thus require no extra overhead for the DBA. The experimental results indicate an improvement of up to 2x, which doubles the longevity of Flash SSD. During the demonstration the audience can experience the advantages of the proposed approach on real Flash hardware. KW - native Flash interface KW - Flash management KW - FTL KW - storage manager KW - data placement KW - region Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bsz:rt2-opus4-15494 SP - 605 EP - 608 PB - Gesellschaft für Informatik CY - Bonn ER - TY - CHAP A1 - Hardock, Sergej A1 - Petrov, Ilia A1 - Gottstein, Robert A1 - Buchmann, Alejandro ED - Markl, Volker T1 - In-place appends for real: DBMS overwrites on Flash without erase T2 - Advances in database technology - EDBT 2017 : 20th International Conference on Extending Database Technology, Venice, Italy, March 21-24, 2017 : proceedings N2 - In the present paper we demonstrate a novel approach to handling small updates on Flash called In-Place Appends (IPA). It allows the DBMS to revisit the traditional write behavior on Flash. Instead of writing whole database pages upon an update in an out-of-place manner on Flash, we transform those small updates into update deltas and append them to a reserved area on the very same physical Flash page. In doing so we utilize the commonly ignored fact that under certain conditions Flash memories can support in-place updates to Flash pages without a preceding erase operation. The approach was implemented under Shore-MT and evaluated on real hardware. Under standard update-intensive workloads we observed 67% less page invalidations resulting in 80% lower garbage collection overhead, which yields a 45% increase in transactional throughput, while doubling Flash longevity at the same time. The IPA outperforms In-Page Logging (IPL) by more than 50%. We showcase a Shore-MT based prototype of the above approach, operating on real Flash hardware – the OpenSSD Flash research platform. During the demonstration we allow the users to interact with the system and gain hands on experience of its performance under different demonstration scenarios. These involve various workloads such as TPC-B, TPC-C or TATP. Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bsz:rt2-opus4-15559 UR - https://openproceedings.org/html/pages/2017_edbt.html SN - 978-3-89318-073-8 SP - 586 EP - 589 PB - University of Konstanz, University Library CY - Konstanz ER - TY - CHAP A1 - Hardock, Sergej A1 - Petrov, Ilia A1 - Gottstein, Robert A1 - Buchmann, Alejandro T1 - Selective in-place appends for real: reducing erases on wear-prone DBMS storage T2 - ICDE 2017 : 2017 IEEE 33rd International Conference on Data Engineering : 19-22 April 2017, San Diego, California, USA N2 - In the present paper we demonstrate the novel technique to apply the recently proposed approach of In-Place Appends – overwrites on Flash without a prior erase operation. IPA can be applied selectively: only to DB-objects that have frequent and relatively small updates. To do so we couple IPA to the concept of NoFTL regions, allowing the DBA to place update-intensive DB-objects into special IPA-enabled regions. The decision about region configuration can be (semi-)automated by an advisor analyzing DB-log files in the background. We showcase a Shore-MT based prototype of the above approach, operating on real Flash hardware. During the demonstration we allow the users to interact with the system and gain hands-on experience under different demonstration scenarios. Y1 - 2017 SN - 978-1-5090-6543-1 U6 - http://dx.doi.org/10.1109/ICDE.2017.184 SP - 1375 EP - 1376 PB - IEEE CY - Piscataway, NJ ER - TY - CHAP A1 - Hardock, Sergej A1 - Petrov, Ilia A1 - Gottstein, Robert A1 - Buchmann, Alejandro ED - Chirkova, Rada T1 - From in-place updates to in-place appends: revisiting out-of-place updates on Flash T2 - SIGMOD '17, May 14-19, 2017, Chicago, IL, USA N2 - Under update intensive workloads (TPC, LinkBench) small updates dominate the write behavior, e.g. 70% of all updates change less than 10 bytes across all TPC OLTP workloads. These are typically performed as in-place updates and result in random writes in page-granularity, causing major write-overhead on Flash storage, a write amplification of several hundred times and lower device longevity. In this paper we propose an approach that transforms those small in-place updates into small update deltas that are appended to the original page. We utilize the commonly ignored fact that modern Flash memories (SLC, MLC, 3D NAND) can handle appends to already programmed physical pages by using various low-level techniques such as ISPP to avoid expensive erases and page migrations. Furthermore, we extend the traditional NSM page-layout with a delta-record area that can absorb those small updates. We propose a scheme to control the write behavior as well as the space allocation and sizing of database pages. The proposed approach has been implemented under Shore- MT and evaluated on real Flash hardware (OpenSSD) and a Flash emulator. Compared to In-Page Logging it performs up to 62% less reads and writes and up to 74% less erases on a range of workloads. The experimental evaluation indicates: (i) significant reduction of erase operations resulting in twice the longevity of Flash devices under update-intensive workloads; (ii) 15%-60% lower read/write I/O latencies; (iii) up to 45% higher transactional throughput; (iv) 2x to 3x reduction in overall write amplification. Y1 - 2017 SN - 978-1-4503-4197-4 U6 - http://dx.doi.org/10.1145/3035918.3035958 SP - 1571 EP - 1586 PB - ACM Association for Computing Machinery CY - New York, NY ER - TY - CHAP A1 - Gottstein, Robert A1 - Petrov, Ilia A1 - Buchmann, Alejandro ED - Laux, Friedrich ED - Strömbäck, Lena T1 - Aspects of append-based database storage management on flash memories T2 - DBKDA 2013, the Fifth International Conference on Advances in Databases, Knowledge, and Data Applications : January 27 - February 1, 2013, Seville, Spain N2 - New storage technologies, such as Flash and Non- Volatile Memories, with fundamentally different properties are appearing. Leveraging their performance and endurance requires a redesign of existing architecture and algorithms in modern high performance databases. Multi-Version Concurrency Control (MVCC) approaches in database systems, maintain multiple timestamped versions of a tuple. Once a transaction reads a tuple the database system tracks and returns the respective version eliminating lock-requests. Hence under MVCC reads are never blocked, which leverages well the excellent read performance (high throughput, low latency) of new storage technologies. Upon tuple updates, however, established implementations of MVCC approaches (such as Snapshot Isolation) lead to multiple random writes – caused by (i) creation of the new and (ii) in-place invalidation of the old version – thus generating suboptimal access patterns for the new storage media. The combination of an append based storage manager operating with tuple granularity and snapshot isolation addresses asymmetry and in-place updates. In this paper, we highlight novel aspects of log-based storage, in multi-version database systems on new storage media. We claim that multi-versioning and append-based storage can be used to effectively address asymmetry and endurance. We identify multi-versioning as the approach to address dataplacement in complex memory hierarchies. We focus on: version handling, (physical) version placement, compression and collocation of tuple versions on Flash storage and in complex memory hierarchies. We identify possible read- and cacherelated optimizations. KW - multi version concurrency control KW - snapshot isolation KW - append storage KW - data placement Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bsz:rt2-opus4-4068 UR - http://www.thinkmind.org/index.php?view=instance&instance=DBKDA+2013 SN - 978-1-61208-247-9 SP - 125 EP - 129 ER -