Dynamic lineage tracking of database data

    公开(公告)号:US11194782B2

    公开(公告)日:2021-12-07

    申请号:US17232927

    申请日:2021-04-16

    Applicant: Snowflake Inc.

    Abstract: The subject technology executes a change on an existing micro-partition of a table, the executing of the change comprising generating a new micro-partition that embodies the change and deleting the existing micro-partition. The subject technology receives a request for a delta for the table between a first timestamp and a second timestamp. The subject technology responsively determines the delta based on a table history, the delta including information indicating at least one operation that was performed to at least one row of a set of rows of the table, without including information as to intermediate changes made to at least one row of the set of rows of the table between the first timestamp and the second timestamp, that facilitates a reduction in storage of historical versions of the set of rows of the table.

    Querying over external tables in database systems

    公开(公告)号:US11163756B2

    公开(公告)日:2021-11-02

    申请号:US16385774

    申请日:2019-04-16

    Applicant: Snowflake Inc.

    Abstract: Systems, methods, and devices for querying over an external table are disclosed. A method includes connecting a database platform to an external table such that the database platform has read access for the external table and does not have write access for the external table. The method includes receiving a query comprising a predicate, the query directed at least to data in the external table. The method includes determining, based on metadata, one or more partitions in the external table comprising data satisfying the predicate. The method includes pruning, based on the metadata, all partitions in the external table that do not comprise any data satisfying the predicate. The method includes generating a query plan comprising a plurality of discrete subtasks. The method includes assigning, based on the metadata, the plurality of discrete subtasks to one or more nodes in an execution platform.

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