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    Bitmap-based count distinct query rewrite in a relational SQL algebra
    32.
    发明授权
    Bitmap-based count distinct query rewrite in a relational SQL algebra 有权

    公开(公告)号：US11379476B2

    公开(公告)日：2022-07-05

    申请号：US16653639

    申请日：2019-10-15

    Applicant: Oracle International Corporation

    Inventor： Sabina Petride ,  Mohamed Ziauddin ,  Praveen T. J. Kumar ,  Huagang Li ,  Andrew Witkowski ,  Sankar Subramanian

    IPC: G06F16/00 ,  G06F16/2453 ,  G06F16/22 ,  G06F16/23 ,  G06F16/242

    Abstract: Techniques are described for storing and maintaining, in a materialized view, bitmap data that represents a bitmap of each possible distinct value of an expression and rewriting a query for a count of distinct values of the expression using the materialized view. The materialized view contains bitmap data that represents a bitmap of each possible distinct value of a first expression, and aggregate values of additional expressions, and is stored in memory or on disk by a database system. The database system receives a query that requests a number of distinct values, of the first expression, and an aggregate value for an additional expression. In response, the database system, rewrites the query to: compute the number of distinct values by counting the bits in the bitmap data of the materialized view that are set to the first value, and obtains the aggregate value for the additional expression in the materialized view.

    Materialized view rewrite technique for one-sided outer-join queries
    35.
    发明授权
    Materialized view rewrite technique for one-sided outer-join queries 有权

    公开(公告)号：US11086868B2

    公开(公告)日：2021-08-10

    申请号：US16667527

    申请日：2019-10-29

    Applicant: Oracle International Corporation

    Inventor： Rafi Ahmed ,  Randall Bello ,  Andrew Witkowski

    IPC: G06F16/245 ,  G06F16/2453

    Abstract: A one-sided outer-join-based query is rewritten using a materialized view (MV), the definition of which includes the join but does not include a filter predicate from the query. The rewritten query nullifies data from the include-matching table, included in the MV, that does not satisfy the filter predicate. To improve accuracy of the query results, certain rows are removed from intermediate results of the query. To facilitate revising the query results for accuracy, the MV includes a unique column from the include-all table and also an indicator column that indicates whether a given row of the MV is an inner-join-type row or an anti-join-type row. The rewritten query adjusts the indicator values, in the indicator column, of MV rows that do not satisfy the filter to reflect a modified anti-join-type indicator value. Based on the modified indicator values and unique columns from include-all tables, accuracy of query results is attained.

    MATERIALIZED VIEW REWRITE TECHNIQUE FOR ONE-SIDED OUTER-JOIN QUERIES
    36.
    发明申请
    MATERIALIZED VIEW REWRITE TECHNIQUE FOR ONE-SIDED OUTER-JOIN QUERIES 有权

    公开(公告)号：US20210124742A1

    公开(公告)日：2021-04-29

    申请号：US16667527

    申请日：2019-10-29

    Applicant: Oracle International Corporation

    Inventor： Rafi Ahmed ,  Randall Bello ,  Andrew Witkowski

    IPC: G06F16/2453

    Abstract: A one-sided outer-join-based query is rewritten using a materialized view (MV), the definition of which includes the join but does not include a filter predicate from the query. The rewritten query nullifies data from the include-matching table, included in the MV, that does not satisfy the filter predicate. To improve accuracy of the query results, certain rows are removed from intermediate results of the query. To facilitate revising the query results for accuracy, the MV includes a unique column from the include-all table and also an indicator column that indicates whether a given row of the MV is an inner-join-type row or an anti-join-type row. The rewritten query adjusts the indicator values, in the indicator column, of MV rows that do not satisfy the filter to reflect a modified anti-join-type indicator value. Based on the modified indicator values and unique columns from include-all tables, accuracy of query results is attained.

    In-memory cursor duration temp tables
    37.
    发明授权
    In-memory cursor duration temp tables 有权

    公开(公告)号：US10452655B2

    公开(公告)日：2019-10-22

    申请号：US15268519

    申请日：2016-09-16

    Applicant: Oracle International Corporation

    Inventor： Janaki Latha Lahorani ,  You Jung Kim ,  Andrew Witkowski ,  Sankar Subramanian

    IPC: G06F17/30 ,  G06F16/2453 ,  G06F16/2455

    Abstract: Techniques are provided herein for processing a query using in-memory cursor duration temporary tables. The techniques involve storing a part of the temporary table in memory of nodes in a database cluster. A part of the temporary table may be stored in disk segments of nodes in the database cluster. Writer threads running on a particular node writes data for the temporary table to the memory of the particular node. Excess data may be written to the disk segment of the particular node. Reader threads running on the particular node reads data for the temporary table from the memory of the particular node and the disk segment of the particular node.

    REDUNDANT GROUP BY AND DISTINCT REMOVAL
    38.
    发明申请
    REDUNDANT GROUP BY AND DISTINCT REMOVAL 审中-公开

    公开(公告)号：US20190026332A1

    公开(公告)日：2019-01-24

    申请号：US15658249

    申请日：2017-07-24

    Applicant: Oracle International Corporation

    Inventor： Rafi Ahmed ,  Andrew Witkowski ,  Sankar Subramanian

    IPC: G06F17/30

    Abstract: A method, apparatus, and stored instructions are provided for the removal of redundant GROUP BY and/or DISTINCT. Every table in the FROM clause of the query block must be a qualified table for the GROUP-BY clause or the DISTINCT keyword in the SELECT clause of the query block to be removed. A table Tx that satisfies at least one of the following two conditions is referred to as a qualified table: (1) Tx has a non-null unique column Tx.u that appears on the GROUP BY clause or the SELECT clause that contains a DISTINCT keyword and (2) There is a qualified table Ty and Ty has a filtering join with Tx.

    SORT-MERGE BAND JOIN OPTIMIZATION
    40.
    发明申请
    SORT-MERGE BAND JOIN OPTIMIZATION 审中-公开

    公开(公告)号：US20180101573A1

    公开(公告)日：2018-04-12

    申请号：US15726030

    申请日：2017-10-05

    Applicant: Oracle International Corporation

    Inventor： Lei Sheng ,  Rafi Ahmed ,  Andrew Witkowski ,  Sankar Subramanian

    IPC: G06F17/30

    CPC classification number: G06F16/24544 ,  G06F16/24537

    Abstract: Techniques herein optimize sort-merge join method for a band join. In an embodiment, for a query comprising a query block specifying a join between a first table and a second table, a band join condition is detected between the first table and the second table. Once the band join condition in detected, an execution plan is generated and executed. The execution of the execution plan includes: for a first row of at least a subset of first sorted rows, scanning second rows from a set of second sorted rows, joining each of said second rows with said first row, and ceasing to scan when encountering a row from the second sorted rows that falls outside a bound of said band join condition. Techniques also include parallelizing a workload by overlapping the distribution of rows to the same slave process and computing cost and cardinality estimation for enhanced band join.

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