公开(公告)号：WO2023086322A1

公开(公告)日：2023-05-19

申请号：PCT/US2022/049235

申请日：2022-11-08

Applicant: GOOGLE LLC

Inventor： MA, Xiaobin ,  CHENG, Xun ,  SHAH, Viral ,  AMIRISHETTY, Anjan, Kumar

IPC: G06F16/2453 ,  G06F16/2455

Abstract: Aspects of the disclosure are directed to late materialization of attributes in response to queries to a database implementing a database cache. Queried data is materialized in temporary memory before the data is projected as part of generating a result to the query. Instead of materializing all of the attributes referenced in a query before executing the query, a database management system materializes attributes as "late" as possible—when the operation needing the attributes is executed. The operation needing the attributes can be performed sooner, as opposed to materializing all referenced attributes are materialized before executing the query.

公开(公告)号：WO2022019985A1

公开(公告)日：2022-01-27

申请号：PCT/US2021/030717

申请日：2021-05-04

Applicant: GOOGLE LLC

Inventor： AMIRISHETTY, Anjan Kumar ,  CHENG, Xun ,  SHAH, Viral

IPC: G06F12/0893 ,  G06F16/22 ,  G06F12/0875

Abstract: A method includes receiving cache configuration information (22) indicating a maximum size (24) and an incremental size (26) for a cache (160) associated with a user (12). The cache is configured to store a portion of a table (158) in a row-major format. The method includes caching, in a column-major format, a subset of a plurality of columns (310) of the table in the cache and receiving a plurality of data requests requesting access to the table and associated with a corresponding access pattern (180) requiring access to one or more of the columns. While executing one or more workloads, the method includes, for each column of the table, determining an access frequency (182) indicating a number of times the corresponding column is accessed over a predetermined time period and dynamically adjusting the subset of columns based on the access patterns, the maximum size, and the incremental size.

公开(公告)号：WO2023086387A1

公开(公告)日：2023-05-19

申请号：PCT/US2022/049407

申请日：2022-11-09

Applicant: GOOGLE LLC

Inventor： HUANG, Haoyu ,  JAIN, Gaurav ,  CHENG, Xun ,  SHAH, Viral ,  BREVDO, Eugene ,  DOSHI, Lyric, Pankaj

IPC: G06F16/22 ,  G06F16/2455

Abstract: Aspects of the disclosure are directed to generating cache configurations for caching data for a database. A database management system (DBMS) can search for column data to cache in a database cache to improve performance of the DBMS in resolving queries. Column data selection can be performed automatically and in the background of a deployed DBMS. Periodically, the DBMS can assess the performance benefit of having certain data cached in the database cache and select data for caching based on the assessed performance benefit. The DBMS can also determine the performance benefit of cached data when not cached, as well as select some portions of data to cache over others. The DBMS can also select data for caching based on different degrees of compression, to further improve query resolution performance.

公开(公告)号：WO2023081153A1

公开(公告)日：2023-05-11

申请号：PCT/US2022/048578

申请日：2022-11-01

Applicant: GOOGLE LLC

Inventor： MA, Xiaobin ,  CHENG, Xun ,  SHAH, Viral ,  AMIRISHETTY, Anjan, Kumar

IPC: G06F16/2452

Abstract: Aspects of the disclosure are directed to generating a hybrid query execution plan for executing queries on database systems implementing a columnar cache. A hybrid query execution plan combines a query execution plan for querying and retrieving data from a columnar cache and a base table. A columnar cache stores cached data in column-major format, which is logically represented by the database management system in row-major format. A database management system as described herein can scan valid blocks of column data according to a column scan operation. The system can identify invalidated blocks and execute a different sub-execution plan of the hybrid query execution plan to scan corresponding rows in tables corresponding to the location of data for the invalidated blocks.