Abstract: To process a sequence of outer joins in a database system, the database system performs a first outer join of the sequence of outer joins. A result of the first outer join is stored in a result table stored across plural storage modules of the database system. At least a subset of records of the result table is redistributed across the storage modules according to a first join attribute of the result table, where any record of the result table that has a null value for the first join attribute is not redistributed. A second outer join of the sequence is performed using the redistributed result table and another table, where the second outer join is based on the first join attribute of the result table.

Abstract: In general, a technique or mechanism is provided to efficiently transfer data of a distributed file system to a parallel database management system using an algorithm that avoids or reduces sending of blocks of files across computer nodes on which the parallel database management system is implemented.

Abstract: A database system receives a transaction that selects values of a column of a first table based on one or more conditions, the column in the first table being according to a first data type. The database system transforms the first data type to a second, different data type. The selected values of the column according to the second data type are stored in the second table.

Abstract: A database system receives a transaction specifying one or more conditions to apply to a first table, and inserts data selected in the transaction into a second. The database system further generates a value list used for compressing a column of the second table, where generating the value list comprises one of inheriting entries of the value list from another value list associated with the first table, and deriving the value list based on the one or more conditions to apply on the first table.