Ocient Holdings LLC

Samuel Peter Bove

Ellis Mihalko Saupe

Sarah Kate Schieferstein

Susmita Saha

Greg R Dhuse

Jason Arnold

George Kondiles

Max Guthmann

Ryan Joseph Kluzinski

Andrew Park

A database system operates by: determining a query for execution against a dataset that indicates a filtering predicate denoting a disjunction between a first range-based predicate and a second range-based predicate; accessing distribution data for the dataset indicating a plurality of kernels for a plurality of points in a multi-dimensional space; identifying a first sub-region within the multi-dimensional space corresponding to the first range-based predicate; identifying a second sub-region within the multi-dimensional space corresponding to the second range-based predicate; computing a disjunction probability approximation value based on an average portion summation value across a plurality of portion summation values generated for the plurality of kernels; and executing the query based on the disjunction probability approximation value.

Query execution in database systems based on disjunction probability

A query processing system operates by: determining a query for execution that indicates a join expression and further indicates a threshold maximum number of output rows for the join expression; determining a query operator execution flow for the join expression that includes performance of two join operations based on the threshold maximum number of output rows for the join expression, wherein a union of output of the two join operations is semantically equivalent to an output of the join expression; and executing the query based on: performing the two join operations in parallel upon sets of input rows; and based on determining a set of output rows outputted by the two join operations has reached the threshold maximum number of output rows, finalizing execution of the query before at least one of the two join operations has finished processing its input rows.

Query processing with limit optimization in a database system

A method for execution by at least one processor of a database system includes determining whether a first operator of a query execution plan is an input to a second operator of the query execution plan such that the second operator is trapped at a non-leaf level of the query execution plan. When the second operator is trapped at the non-leaf level of the query execution plan, the method further includes generating an updated query execution plan, wherein the updated query execution plan includes the first operator being distributed to produce a plurality of distributed first operators such that the second operator executes at a lower level than the non-leaf level of the query execution plan. The method further includes executing the updated query execution plan to produce a query resultant.

Distributed limit processing in a database system

A database system is operable to determine a query that includes a join expression for execution. A set of input rows are dispersed for processing via a plurality of parallelized join processes in conjunction with executing the join expression based on identifying a first proper subset of the set of input rows based on a null-handling strategy. First rows in the first proper subset are dispersed for processing across the plurality of parallelized join processes in accordance with the null-handling strategy. second rows in a set difference between the set of input rows and the first proper subset are dispersed across the plurality of parallelized join processes in accordance with a join key-based assignment strategy. The set of input rows are processed via the plurality of parallelized join processes.

Handling null values in processing join operations during query execution

A database system is operable to generate query output based on executing a plurality of operators of a query operator execution flow for a query. Executing each operator can include generating a set of output query rows based on processing a set of input query rows, maintaining execution tracking data for the each operator that includes at least one counter tracking at least one event type, and generating a set of execution tracking rows based on sampling the execution tracking data. The query output includes a final set of rows corresponding to a query resultant and a final set of execution tracking rows generated by at least one final operator based on an aggregation of a plurality of sets of execution tracking rows generated by the plurality of operators.

Generating execution tracking rows during query execution via a database system

A database system is operable to determine a query for execution. The database system can execute a left join operation for the query based on receiving a plurality of left input rows, and forwarding all of the plurality of left input rows are forwarded. It is determined whether any right input rows match with each given left input row based on a hash map. When one right input row is identified as matching with the given left input row, a value of right input row is copied and emitted in conjunction with the given left input row. When no right input rows are identified as matching with the given left input row, a null value is emitted in conjunction with the given left input row.

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Chicago, IL, United States of America

Samuel Peter Bove