Maintaining data across query executions of a long-running query

摘要

Disclosed herein are system, method, and computer program product embodiments for a query processing system. An embodiment operates by receiving a query associated with a table. An ordered index with entries that include key values that uniquely identifies a corresponding record in the table is determined. A last key value is initialized to store a minimum value for a data type of the key value. The query is executed as a union-all of a plurality of queries. While a count of selected records is less than or equal to a threshold quantity and at least one entry remains in the ordered index, an ordered next entry with a key value subsequent to the last key value in the index is identified, the corresponding record is selected from the table, the last key value is updated, the query is executed, and the count is incremented.