公开(公告)号：US10915576B2

公开(公告)日：2021-02-09

申请号：US16364509

申请日：2019-03-26

Applicant: SAP SE

Inventor： Thomas Legler

IPC: G06F16/90 ,  G06F16/901 ,  G06F16/903 ,  G06F12/0868

Abstract: A method may include identifying, based on a first hash representation of a value, a first cache line corresponding to the value. A first bit and a second bit in the cache line may be identified as corresponding to the value based on a second hash representation of the value. The first bit may be identified based on a first offset in a binary representation of the second hash representation. The second bit may be identified based on a second offset in the binary representation of the second hash representation. Each of the first offset and the second offset may include a portion of the binary digits forming the binary representation of the second hash representation. The value may be determined to be absent from a set of values based the first bit and/or the second bit being set to a first value instead of a second value.

公开(公告)号：US20200311139A1

公开(公告)日：2020-10-01

申请号：US16364509

申请日：2019-03-26

Applicant: SAP SE

Inventor： Thomas Legler

IPC: G06F16/901 ,  G06F12/0868 ,  G06F16/903

Abstract: A method may include identifying, based on a first hash representation of a value, a first cache line corresponding to the value. A first bit and a second bit in the cache line may be identified as corresponding to the value based on a second hash representation of the value. The first bit may be identified based on a first offset in a binary representation of the second hash representation. The second bit may be identified based on a second offset in the binary representation of the second hash representation. Each of the first offset and the second offset may include a portion of the binary digits forming the binary representation of the second hash representation. The value may be determined to be absent from a set of values based the first bit and/or the second bit being set to a first value instead of a second value.

公开(公告)号：US20200293507A1

公开(公告)日：2020-09-17

申请号：US16890446

申请日：2020-06-02

Applicant: SAP SE

Inventor： Klaus Otto Mueller ,  Thomas Legler

IPC: G06F16/22 ,  G06F9/445 ,  G06F16/23 ,  G06F16/2458

Abstract: A system for unloading tables of a database is provided. In some aspects, the system performs operations including determining that a number of accesses to a table occurring within a time period has satisfied an access threshold. The operations may further include identifying, in response to the determining, a first timestamp indicating a most recent access to the table. The operations may further include determining whether a difference between a current timestamp and the first timestamp satisfies a first time threshold. The operations may further include comparing, in response to the difference satisfying the first time threshold, a ratio of the difference and a size of the table to a ratio threshold. The operations may further include unloading, in response to satisfying the ratio threshold, the table. The operations may further include adjusting, based on the feedback, the first time threshold and/or the ratio threshold.

公开(公告)号：US20190339954A1

公开(公告)日：2019-11-07

申请号：US15973058

申请日：2018-05-07

Applicant: SAP SE

Inventor： Thomas Legler

IPC: G06F8/41 ,  G06F12/0862 ,  G06F17/30

Abstract: A system for cache efficient reading of column values in a database is provided. In some aspects, the system performs operations including pre-fetching, asynchronously and in response to a request for data in a column store database system, a plurality of first values associated with the requested data. The request may identify a row of the column store database system associated with the requested data. The plurality of first values may be located in the row. The operations may further include storing the plurality of first values in a cache memory. The operations may further include pre-fetching, asynchronously and based on the plurality of first values, a plurality of second values. The operations may further include storing the plurality of second values in the cache memory. The operations may further include reading, in response to the storing the plurality of second values, the requested data from the cache memory.

公开(公告)号：US20190311051A1

公开(公告)日：2019-10-10

申请号：US15945723

申请日：2018-04-04

Applicant: SAP SE

Inventor： Thomas Legler ,  Andreas Tonder

IPC: G06F17/30

Abstract: A system for implementing virtual columns in a column store database is provided. In some implementations, the system performs operations including accessing a database table in a column store database system, the database table comprising at least one virtual column, the column store database system storing data in a column-oriented structure. The operations further include calculating a value for the at least one virtual column based on at least one existing column of the database table, the calculated value mapped to a row identifier associated with a row of the database table. The operations further include providing, in response to a query, the calculated value to a user interface, the query associated with the row identifier.

公开(公告)号：US10275399B2

公开(公告)日：2019-04-30

申请号：US14944087

申请日：2015-11-17

Applicant: SAP SE

Inventor： Peter Steinemann ,  Thomas Legler

IPC: G06F17/30 ,  G06F16/22 ,  G06F16/2455 ,  G06F16/901

Abstract: A ValueID corresponding to a value to be searched for in a database column can be determined by finding a match in a dictionary for the database column. A row of an index vector for the database column at which to begin a scan for the ValueID can be identified by reading a ValueID lookup table that maps each unique ValueID to a starting position in the index vector for the database column. The ValueID can not occur in the index vector prior to the starting position. The index vector can be scanned beginning at the starting position to find at least one occurrence of the ValueID corresponding to the value being searched, and a result that includes one or more row locations in the database column corresponding to the at least one occurrence in the index vector of the ValueID corresponding to the value being searched can be returned.

公开(公告)号：US12235878B2

公开(公告)日：2025-02-25

申请号：US18212327

申请日：2023-06-21

Applicant: SAP SE

Inventor： Thomas Legler

IPC: G06F16/31 ,  G06F16/33 ,  G06F16/334 ,  G06F16/338

Abstract: Example methods and systems are directed to inverted indexes. According to some examples, an inverted index is generated based on source data and a posting list threshold. The inverted index comprises one or more restricted posting lists. Each restricted posting list has a maximum size corresponding to the posting list threshold. The method may include receiving a search query comprising a value that identifies a restricted posting list of the one or more restricted posting lists. The value may be used to retrieve and return one or more record identifiers from the identified restricted posting list. A record identifier uniquely identifies one of the plurality of records in the source data.

公开(公告)号：US20240427806A1

公开(公告)日：2024-12-26

申请号：US18212327

申请日：2023-06-21

Applicant: SAP SE

Inventor： Thomas Legler

IPC: G06F16/31 ,  G06F16/33 ,  G06F16/338

Abstract: Example methods and systems are directed to inverted indexes. According to some examples, an inverted index is generated based on source data and a posting list threshold. The inverted index comprises one or more restricted posting lists. Each restricted posting list has a maximum size corresponding to the posting list threshold. The method may include receiving a search query comprising a value that identifies a restricted posting list of the one or more restricted posting lists. The value may be used to retrieve and return one or more record identifiers from the identified restricted posting list. A record identifier uniquely identifies one of the plurality of records in the source data.

公开(公告)号：US11119742B2

公开(公告)日：2021-09-14

申请号：US16565254

申请日：2019-09-09

Applicant: SAP SE

Inventor： Thomas Legler

IPC: G06F12/08 ,  G06F8/41 ,  G06F12/0862 ,  G06F16/22 ,  G06F16/2455 ,  G06F12/0844

Abstract: A system for cache efficient reading of column values in a database is provided. In some aspects, the system performs operations including pre-fetching, asynchronously and in response to a request for data in a column store database system, a plurality of first values associated with the requested data. The request may identify a row of the column store database system associated with the requested data. The plurality of first values may be located in the row. The operations may further include storing the plurality of first values in a cache memory. The operations may further include pre-fetching, asynchronously and based on the plurality of first values, a plurality of second values. The operations may further include storing the plurality of second values in the cache memory. The operations may further include reading, in response to the storing the plurality of second values, the requested data from the cache memory.

公开(公告)号：US20210271676A1

公开(公告)日：2021-09-02

申请号：US16805624

申请日：2020-02-28

Applicant: SAP SE

Inventor： Oliver Horn ,  Thomas Legler ,  Robert Schulze

IPC: G06F16/2453 ,  G06F16/22 ,  G06F16/2455

Abstract: In some example embodiments, there may be provided a method including detecting a query operator of a predetermined type requiring a sorting or a scanning responsive to the query operator at a column-oriented database; determining a sorted dictionary at the column-oriented database is eligible for direct access by at least checking that the column-oriented database provides sorted dictionary access and that dictionary collation and a collation of the query operator are the same; when the sorted dictionary is eligible, reading directly from the sorted dictionary a batch of sorted values; and processing, based on the batch sorted values read from the sorted dictionary, the query operator.