Tracking and maintaining expression statistics across database queries

    公开(公告)号:US10372706B2

    公开(公告)日:2019-08-06

    申请号:US15146798

    申请日:2016-05-04

    Abstract: Techniques are described for maintaining an expression statistics store that stores and updates metadata values for query expressions based on the occurrence of those query expressions within queries. In an embodiment, a database server instance receives a database query. In response, the database server instance identifies expressions within the database queries. The database server instance then determines whether an expression statistics store includes an entry for the particular expression. Responsive to determining that the expression statistics store includes an entry for the particular expression, the database server instance updates at least one metadata value in the entry based on the occurrence of the particular expression. Responsive to determining that the expression statistics store does not include an entry for the particular expression, the database server instance adds an entry for the particular expression.

    EFFICIENT EVALUATION OF AGGREGATE FUNCTIONS
    27.
    发明申请

    公开(公告)号:US20180075113A1

    公开(公告)日:2018-03-15

    申请号:US15702526

    申请日:2017-09-12

    Abstract: Techniques related to efficient evaluation of aggregate functions are disclosed. Computing device(s) may perform a method for aggregating results of performing a multiplication on a first column and a second column of a database table. A first vector stores a subset of values of the first column. A second vector stores a corresponding subset of values of the second column. When it is determined that the first vector has a lower cardinality than the second vector, a third vector stores at least a first distinct value and a second distinct value of the first vector. A first set of one or more values of the second vector is determined, wherein each value of the first set of one or more values corresponds to the first distinct value in the first vector. A first multiplicand is generated based on performing a summation over the first set of one or more values.

    TRACKING AND MAINTAINING EXPRESSION STATISTICS ACROSS DATABASE QUERIES
    29.
    发明申请
    TRACKING AND MAINTAINING EXPRESSION STATISTICS ACROSS DATABASE QUERIES 审中-公开
    跟踪和维护数据库查询中的表达统计

    公开(公告)号:US20170031967A1

    公开(公告)日:2017-02-02

    申请号:US15146798

    申请日:2016-05-04

    Abstract: Techniques are described for maintaining an expression statistics store that stores and updates metadata values for query expressions based on the occurrence of those query expressions within queries. In an embodiment, a database server instance receives a database query. In response, the database server instance identifies expressions within the database queries. The database server instance then determines whether an expression statistics store includes an entry for the particular expression. Responsive to determining that the expression statistics store includes an entry for the particular expression, the database server instance updates at least one metadata value in the entry based on the occurrence of the particular expression. Responsive to determining that the expression statistics store does not include an entry for the particular expression, the database server instance adds an entry for the particular expression.

    Abstract translation: 描述了用于维护表达式统计存储的技术,该表达式统计存储根据查询中的那些查询表达式的出现来存储和更新查询表达式的元数据值。 在一个实施例中,数据库服务器实例接收数据库查询。 作为响应,数据库服务器实例标识数据库查询中的表达式。 然后,数据库服务器实例确定表达式统计信息存储是否包含特定表达式的条目。 响应于确定表达式统计存储器包括特定表达式的条目,数据库服务器实例基于特定表达式的出现来更新条目中的至少一个元数据值。 响应于确定表达式统计信息存储不包含特定表达式的条目,数据库服务器实例为特定表达式添加条目。

    EFFICIENT HARDWARE INSTRUCTIONS FOR SINGLE INSTRUCTION MULTIPLE DATA PROCESSORS
    30.
    发明申请
    EFFICIENT HARDWARE INSTRUCTIONS FOR SINGLE INSTRUCTION MULTIPLE DATA PROCESSORS 有权
    高效的硬件指令,用于单个指令多个数据处理器

    公开(公告)号:US20140013078A1

    公开(公告)日:2014-01-09

    申请号:US14023265

    申请日:2013-09-10

    Abstract: A method and apparatus for efficiently processing data in various formats in a single instruction multiple data (“SIMD”) architecture is presented. Specifically, a method to unpack a fixed-width bit values in a bit stream to a fixed width byte stream in a SIMD architecture is presented. A method to unpack variable-length byte packed values in a byte stream in a SIMD architecture is presented. A method to decompress a run length encoded compressed bit-vector in a SIMD architecture is presented. A method to return the offset of each bit set to one in a bit-vector in a SIMD architecture is presented. A method to fetch bits from a bit-vector at specified offsets relative to a base in a SIMD architecture is presented. A method to compare values stored in two SIMD registers is presented.

    Abstract translation: 提出了一种在单指令多数据(“SIMD”)结构中有效处理各种格式的数据的方法和装置。 具体地说,提出了一种在SIMD架构中将位流中的固定宽度位值解包为固定宽度字节流的方法。 介绍了一种解码SIMD架构中字节流中可变长度字节打包值的方法。 提出了一种在SIMD架构中解压缩运行长度编码的压缩位向量的方法。 提出了一种在SIMD架构中将位设置为1的偏移量返回到位向量中的方法。 提出了一种从SIMD架构中相对于基址指定的偏移量从位向量获取位的方法。 提出了一种比较存储在两个SIMD寄存器中的值的方法。

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