Abstract: 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.

Abstract: A database system is operable to determine a query for execution. A disjunction of a plurality of conjunctive normal form (CNF) filtering predicates is determined based on filtering predicates of the query. An IO pipeline is generated based on the disjunction of the plurality of CNF filtering predicates that includes, based on applying at least one type of optimization, at least one shared IO element common to multiple ones of plurality of the CNF filtering predicates. The IO pipeline is executed in accordance with execution of the query to generate a filtered subset of a plurality of rows that each meet at least one of the plurality of CNF filtering predicates.

Abstract: 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.

Abstract: A database system is operable to generate and a first plurality of column-formatted segments from a first plurality of rows. A query indicates parameters for generating a result set, and further indicating an instruction to store the result set. A query operator execution flow that includes a loading operator is generated. The query is executed based on accessing at least one of the first plurality of rows, processing the at least one of the first plurality of rows to generate a second plurality of rows as the result set, and executing the loading operator. At least one new column-formatted segment is from the second plurality of rows based on execution of the loading operator. The at least one new column-formatted segment is stored access in future query executions.