Abstract: A number, of the blocks of data to be prefetched into a buffer cache, is determined dynamically at run time (e.g. during execution of a query), based at least in part on the load placed on the buffer cache. An application program (such as a database) is responsive to the number (also called “prefetch size”), to determine the amount of prefetching. A sequence of instructions (also called “prefetch size daemon”) computes the prefetch size based on, for example, the number of prefetched blocks aged out before use. The prefetch size daemon dynamically revises the prefetch size based on usage of the buffer cache, thereby to form a feedback loop. Depending on the embodiment, at times of excessive use of the buffer cache, prefetching may even be turned off.

Abstract: A method and apparatus for efficiently transmitting a result set. A data server receives a data request from a client or another server. The data server determines whether a threshold portion of the contents of each requested row or record is being retrieved (e.g., X% of the number of columns in a table or X% of the total amount of data in a table row). The requested rows are retrieved in the same format in which they are stored (e.g., within a disk block), and streamed to the client, one row at a time. The client is then responsible for disassembling a row into its columns, reordering them if necessary, and performing any necessary post-processing (e.g., datatype conversion, data formatting) before consuming the data.