Tablespace-relative database pointers
AssigneeOracle Corporation
InventorsWilliam H. Bridge, Jr., Jonathan D. Klein, J. William Lee, Juan R. Loaiza, Alex Tsukerman, GianFranco Putzolu
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Abstract
A database containing datafiles is partitioned into a set of tablespaces. Every disk pointer pointing to a data item in a datafile refers to a tablespace-relative file number for the datafile. Data pointed to by a tablespace-relative disk pointer is retrieved by first checking the cache, and upon a cache miss, the tablespace-relative file number is translated into an absolute file number according to a latch-free look up technique.
Claims19
A method of retrieving information from a computer database having a plurality of datafiles, said plurality of datafiles containing a plurality of data items, the method comprising the computer-implemented steps of:
- logically partitioning said plurality of datafiles into a plurality of tablespaces;
- storing references to data items that are contained in said plurality of datafiles as tablespace-relative pointers, wherein each of said tablespace-relative pointers indicates a location of a corresponding data item relative to the tablespace of said plurality of tablespaces that contains said corresponding data item;
- locating a data item within said plurality of datafiles by performing the steps of:
- reading a tablespace-relative pointer associated with said data item;
- determining, based on an operating context, an identity of the tablespace of said plurality of tablespaces that contains said data item;
- and
- locating said data item based on said tablespace-relative pointer and the identity of the tablespace.
A database system, comprising:
- a plurality of datafiles;
- a plurality of tablespaces, forming a partition of and containing said plurality of datafiles;
- a plurality of data items, contained in said plurality of datafiles;
- and
- a plurality of references to data items stored in said plurality of datafiles as tablespace-relative pointers, wherein each of said tablespace-relative pointers indicates a location of a corresponding data item relative to the tablespace of said plurality of tablespaces that contains said corresponding data item.
A computer readable medium having stored thereon sequences of instructions for retrieving information from a computer database having a plurality of datafiles, said plurality of datafiles containing a plurality of data items, said sequences of instructions including instructions for performing the steps of:
- logically partitioning said plurality of datafiles into a plurality of tablespaces;
- and
- storing references to data items that are contained in said plurality of datafiles as tablespace-relative pointers, wherein each of said tablespace-relative pointers indicates a location of a corresponding data item relative to the tablespace of said plurality of tablespaces that contains said corresponding data item.
Dependencies are inferred from the claim text.