Abstract: A database may facilitate zero-downtime upgrades by concurrently maintaining multiple editions of database objects for use by both pre-upgrade and post-upgrade clients of a database application. Operations performed within the database are associated with an edition based on, for example, an initiating client or transaction. When an operation references an object or data, the database automatically performs the operation using the object or data associated with the edition with which the operation is itself associated. The database may determine the associated edition without explicit identification of the associated edition in a query or in code. Thus, no client or stored procedure code changes are necessary to reflect a new edition added during an update. Data changes in one edition may be automatically and immediately propagated to the other edition through the use of cross-edition triggers, thereby allowing both pre-upgrade and post-upgrade clients to remain fully functional throughout an upgrade.

Abstract: Several techniques for sorting item are described, generally referred to as (1) common prefix skipping quicksort; (2) key substring caching; and (3) adaptive quicksort. With common prefix skipping quicksort, common prefix bytes among all key values for a partition are computed while performing a quicksort partitioning operation, and the known common bytes are skipped when comparing two key values in a recursive partitioning operation. With key substring caching, each item is represented in a cached array comprising a particular number of bytes for respective portions of key values (“key substring”), where the key substring cache is updated contain bytes beyond the known number of common prefix bytes. An adaptive quicksort routine is a hybrid of a quicksort function and most significant digit radix sort function, where the functions are mutually recursive.

Abstract: Order allocation techniques that reduce the number of stops that a container makes in the process of fulfilling a customer order is disclosed. In one embodiment, this is accomplished by first identifying a pod that stocks the largest number of different items in a customer order. Then, a second pod is identified that stocks the largest number of remaining items in the customer order. Ultimately, all items in the customer order are assigned a pod. The collection of pods defines a container path through the distribution center.

Abstract: Techniques are described for combining pieces of information from two sources. The techniques may be used to improve the performance, for example, of hash join operations that are parallelized using slaves distributed across multiple nodes. According to one technique, bitmap filtering operations are performed by the probe-phase producer slaves, rather than the probe-phase consumer slaves. To avoid having to merge separately built bitmap filter chunks, the left-hand rows may be sent to every probe-phase consumer slave. Alternatively, the merge operation may be avoided by distributing the rows of one source based on how the other source has been statically partitioned.

Abstract: Techniques are provided for processing, within a database server, a database statement, where at least one subtask required by the database statement is to be executed in parallel by a slave set. The database server determines whether the database statement includes an external expression, relative to the subtask, that (a) produces information that is required by slave processes in the slave set in order to perform the subtask, and (b) is not to be evaluated by each slave process in the slave set. During execution of the statement, if the database statement includes an external expression, then one or more external values are generated by causing the external expression to be evaluated, and the one or more external values are communicated to slaves of the slave set to allow the slave processes to perform respective portions of the subtask in parallel, without requiring each slave of the slave set to evaluate the external expression.