Oracle International Corporation

Quoc Tai Tran

Michael Charles Depledge

Mark Kremer

Jeffrey Ira Cohen

Cetin Ozbutun

Hakan Jakobsson

Alexander C Ho

Julian Hyde

Santanu Mukhopadhyay

Behrouz Arbab-Dehkordi

William M Keese

Bitmap index compression

A method and apparatus for segmenting bitmaps in a bitmap index is provided. A segmented bitmap includes a plurality of bitmap segments that are used to indicate which records in a body of records that is associated with the segmented bitmap satisfy a particular criteria. Each bitmap segment contains a string of bits that correspond to a corresponding range of records in the body of records. There may be gaps between the ranges represented by the bitmap segments when, for example, the body of records does not contain records in a particular range. For the purposes of retrieval, compression, de-compression, locking and logging, the database system treats each bitmap segment as a distinct data item.

Bitmap segmentation

A method for performing logical operations on bitmap streams from segmented bitmaps. The logical operations include the AND, OR, and Set Minus operations. One embodiment of the invention performs the logical AND operation on a plurality of bitmap streams by searching for a set of overlapping bitmap segments. The ranges corresponding to the overlap among the overlapping bitmap segments are scanned to generate non-gap results. One embodiment of the invention performs the logical OR operation on a plurality of bitmap streams. To generate a result for a given range, only the bitmap segments overlapping the given range are ORed together. One embodiment of the invention performs a Set Minus between bitmap streams. A set minus is the ANDing of a first condition with the negation of another condition. To generate a set minus result, the ranges corresponding to the gaps in the bitmap associated with the negated condition are ignored.

Query processing using compressed bitmaps

A method and apparatus for generating and using bitmaps in a database system that employs multi-level identifiers is provided. The generated bitmaps include bits that correspond to the identifiers that have been assigned to existing records, as well as bits that correspond to all intervening multi-level identifiers that have not yet been assigned. Therefore, when new rows are inserted into the table associated with the bitmap, new bits do not have to be inserted into the existing bitmap. When existing rows are deleted, the bits that correspond to the deleted rows are not themselves deleted, but are simply set to a value that indicates that the corresponding row does not satisfy the criteria associated with the bitmap.

Creating bitmaps from multi-level identifiers

A method for combining within memory a limit, a plurality of bitmap streams from bitmaps of indefinite size and number. The bitmap streams are merged into a resulting bitmap which can be used in subsequent logical operations. In order to perform a merge within a memory limit, the method relies on the data compression. When compression by itself may be ineffective, the method produces a resulting bitmap for a reduced range. The ensures the production of a resulting bitmap. When the range is reduced, the method may be repeated to produce a merge for a range beyond the reduced range.

Combining bitmaps within a memory limit

A method and apparatus provide bitmapped indexing with high granularity locking. Whenever a change is made to a data table upon which a bitmapped index is based, two differential entries are generated and stored as index entries in the bitmapped index. Each differential entry identifies a bit to be flipped in the corresponding bitmap index entry. When applied to corresponding bitmap index entry, the changes are reflected in the appropriate bitmaps. Whenever a bitmap is read from the bitmapped index, any corresponding differential entries are applied so that the resulting bitmap reflects the change made to the data table.

Bitmapped indexing with high granularity locking

A system and apparatus is disclosed which stores, retrieves and analyzes relational and non-relational data. An application program provides a data query statement containing both relational and non-relational portions to a relational server. In an embodiment, the query statement is a Structured Query Language ('SQL') CONTAINS stored procedure or CONTAINS function statement. The relational data server then provides the non-relational query to either a text queue or database management language ('DML') queue. A non-relational data server then accesses either the text queue or the DML queue. The non-relational data server obtains pointers to the non-relational data and stores them in a temporary table. The pointers and relational data portion are processed by the relational server to obtain the relational and non-relational data. In an embodiment, the non-relational data server is a text server including an engine, filter, lexer, data storage and word list.

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Redwood Shores, CA, United States of America

Quoc Tai Tran