| 主权项 |
1. A computer implemented method for operating a database system, the method comprising:
storing a database table comprising a plurality of rows, a first portion of the rows stored in a memory device and a second portion of the rows stored in a disk device; receiving a request relating to a specific row of the database table; accessing, by a computer, an index for the database table, the index comprising entries for each row of the database table stored in the memory device and entries for a subset of the rows of the database table stored in the disk device, wherein the subset of the rows of the database table stored in the disk device are not stored in the memory device and wherein the index has densely indexed rows that correspond to the subset of the rows of the database table stored in memory device and sparsely indexed rows that correspond to the subset of the rows of the database table stored in the disk device; performing, by the computer, a search on the index to determine existence of the specific requested row; determining, by the computer, from the index whether the specific row is stored in the memory device or the disk device based on a key type provided in the index that corresponds to the specific requested row wherein a first key type is provided for rows stored in the memory device and a second key type is provided for rows stored in the disk device, wherein the first key type is an identification of a row address in the memory device and wherein the second key type is an identification of a page address in the disk device; connecting to the memory device responsive to determining that the specific row is stored in the memory device; connecting to the disk device responsive to determining that the specific row is stored in the disk device; and performing an action related to the specific row, the action responsive to the received request. |
