DETECTING DATA SKEW IN A JOIN OPERATION

    公开(公告)号:US20220035814A1

    公开(公告)日:2022-02-03

    申请号:US17502685

    申请日:2021-10-15

    Applicant: Snowflake Inc.

    Abstract: Systems, methods, and devices, for managing data skew during a join operation are disclosed. A method includes computing a hash value for a join operation and detecting data skew on a probe side of the join operation at a runtime of the join operation using a lightweight sketch data structure. The method includes identifying a frequent probe-side join key on the probe side of the join operation during a probe phase of the join operation. The method includes identifying a frequent build-side row having a build-side join key corresponding with the frequent probe-side join key. The method includes asynchronously distributing the frequent build-side row to one or more remote servers.

    SYSTEM AND METHOD FOR DISJUNCTIVE JOINS

    公开(公告)号:US20210326340A1

    公开(公告)日:2021-10-21

    申请号:US17327521

    申请日:2021-05-21

    Applicant: SNOWFLAKE INC.

    Abstract: Joining data using a disjunctive operator is described. An example computer-implemented method can include receiving a query that includes a first disjunctive predicate involving a first table and a second table. The method may also include determining a first set of rows from the first table and generating a filter from the first set of rows. The method may also further include applying the filter to the second table to generate a second set of rows. Additionally, the method may also include joining the first set of rows and the second set of rows using a first disjunctive operator of the first disjunctive predicate to generate a first results set.

    SYSTEM AND METHOD FOR DISJUNCTIVE JOINS

    公开(公告)号:US20210286816A1

    公开(公告)日:2021-09-16

    申请号:US17105406

    申请日:2020-11-25

    Applicant: Snowflake Inc.

    Abstract: Joining data using a disjunctive operator is described. An example computer-implemented method can include receiving a query that includes a first disjunctive predicate involving a first table and a second table. The method may also include determining a first set of rows from the first table and generating a filter from the first set of rows. The method may also further include applying the filter to the second table to generate a second set of rows. Additionally, the method may also include joining the first set of rows and the second set of rows using a first disjunctive operator of the first disjunctive predicate to generate a first results set.

    MULTI-CLUSTER WAREHOUSE
    44.
    发明申请

    公开(公告)号:US20210089560A1

    公开(公告)日:2021-03-25

    申请号:US17118201

    申请日:2020-12-10

    Applicant: SNOWFLAKE INC.

    Abstract: A method for a multi-cluster warehouse includes allocating a plurality of compute clusters as part of a virtual warehouse. The compute clusters are used to access and perform queries against one or more databases in one or more cloud storage resources. The method includes providing queries for the virtual warehouse to each of the plurality of compute clusters. Each of the plurality of compute clusters of the virtual warehouse receives a plurality of queries so that the computing load is spread across the different clusters. The method also includes dynamically adding compute clusters to and removing compute clusters from the virtual warehouse as needed based on a workload of the plurality of compute clusters.

    System and method for disjunctive joins

    公开(公告)号:US12164514B2

    公开(公告)日:2024-12-10

    申请号:US18109099

    申请日:2023-02-13

    Applicant: SNOWFLAKE INC.

    Abstract: Joining data using a disjunctive operator is described. An example computer-implemented method can include generating, with a processing device, a query plan for a query, the query comprising a join operator expression for a disjunctive predicate, wherein the join operator expression includes a conjunctive predicate and a disjunctive operator. The method may further include generating a bloom filter for the disjunctive operator. Additionally, the method may include generating a result set as a result of evaluating the join operator expression using the disjunctive operator and bloom filter for the disjunctive predicate.

    Efficient database query evaluation

    公开(公告)号:US11971856B2

    公开(公告)日:2024-04-30

    申请号:US16779366

    申请日:2020-01-31

    Applicant: Snowflake Inc.

    CPC classification number: G06F16/1744 G06F16/221 G06F16/27

    Abstract: Data in a micro-partition of a table is stored in a compressed form. In response to a database query on the table comprising a filter, the portion of the data on which the filter operates is decompressed, without decompressing other portions of the data. Using the filter on the decompressed portion of the data, the portions of the data that are responsive to the filter are determined and decompressed. The responsive data is returned in response to the database query. When a query is run on a table that is compressed using dictionary compression, the uncompressed data may be returned along with the dictionary look-up values. The recipient of the data may use the dictionary look-up values for memoization, reducing the amount of computation required to process the returned data.

    Systems and methods for spilling data for hash joins

    公开(公告)号:US11868352B2

    公开(公告)日:2024-01-09

    申请号:US18073464

    申请日:2022-12-01

    Applicant: Snowflake Inc.

    CPC classification number: G06F16/2456 G06F16/24554

    Abstract: A method includes determining that an amount of available space in a first memory used by a set of relational queries is insufficient for a query, wherein the query comprises a join operation. A first partition of a set of partitions is identified, wherein the first partition possesses a smallest available probe memory size of the set of partitions and a build memory size greater than or equal to a threshold memory size, wherein the threshold memory size is a percentage of a maximum build memory size, and the largest partition of the set of partitions has the maximum build memory size. The first partition is copied from the first memory to a second memory.

    Multi-cluster warehouse
    50.
    发明授权

    公开(公告)号:US11630850B2

    公开(公告)日:2023-04-18

    申请号:US17116625

    申请日:2020-12-09

    Applicant: SNOWFLAKE INC.

    Abstract: A method for a multi-cluster warehouse includes allocating a plurality of compute clusters as part of a virtual warehouse. The compute clusters are used to access and perform queries against one or more databases in one or more cloud storage resources. The method includes providing queries for the virtual warehouse to each of the plurality of compute clusters. Each of the plurality of compute clusters of the virtual warehouse receives a plurality of queries so that the computing load is spread across the different clusters. The method also includes dynamically adding compute clusters to and removing compute clusters from the virtual warehouse as needed based on a workload of the plurality of compute clusters.

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