公开(公告)号：US20250068605A1

公开(公告)日：2025-02-27

申请号：US18499762

申请日：2023-11-01

Applicant: Snowflake Inc.

Inventor： Christian Diaconu ,  Chen Luo ,  Corbin McElhanney ,  Wumengjian Zhu

IPC: G06F16/21 ,  G06F16/2455 ,  G06F16/2457

Abstract: The subject technology receives a request to perform a table scan operation of a table. The subject technology determines that the table is being accessed for an initial time. The subject technology populates a columnar cache with data of the table provided by the table scan operation. The subject technology determines a set of schema versions of a set of rows from the data of the table. The subject technology determines schema information of each schema from the set of schema versions. The subject technology generates a result rowset and a second rowset comprising a union of columns that have appeared at least once in each row. The subject technology performs deserialization of rows from the result rowset and the second rowset. The subject technology provides the rows from the result rowset and the second rowset to write to a file in a particular format.

公开(公告)号：US12086154B1

公开(公告)日：2024-09-10

申请号：US18455229

申请日：2023-08-24

Applicant: Snowflake Inc.

Inventor： Mihir Dharamshi ,  Cristian Diaconu ,  Chen Luo ,  Andrew McCormick ,  Corbin McElhanney ,  Joshua Slocum ,  Wumengjian Zhu

IPC: G06F16/25 ,  G06F16/11 ,  G06F16/172 ,  G06F16/23

CPC classification number: G06F16/254 ,  G06F16/116 ,  G06F16/172 ,  G06F16/2379

Abstract: The subject technology receives a query, the query including a query range for processing the query. The subject technology sends a request to a key-value store for blob metadata and a set of recent writes for the query range. The subject technology receives the blob metadata, the blob metadata including information related to a set of blob files. The subject technology determines whether the set of blob files is stored in a local cache. The subject technology, in response to at least one blob file being missing from the set of blob files, sends a request to a blob store to retrieve the at least one blob file of the set of blob files. The subject technology transforms the retrieved at least one blob file to a column file format. The subject technology stores the transformed at least one blob file in the local cache.