Abstract: One or more indexes are built on data (concurrent with manipulation of data) wherein the index build operation is done without restricting the manipulation of data. The index is brought to consistency with the data based upon processing recovery log records to simulate index manipulations during data insert, update, or delete operations.

Abstract: A method, apparatus and article of manufacture, implementing the method, for operating a database management system stores information in at least one entry. Each entry is associated with a row. At least one entry comprises one or more columns. At least one of the columns has a varying length. At least one entry comprises an offset array having one or more offsets associated with the columns having the varying length. In another aspect of the invention, a column extraction table is built and used, with the offset array, to access a specified column of an entry. Alternately, code is generated to access a specified column based on the offset array of an entry. In yet another aspect of the invention, a comparison table is built and used, with the offset array, to compare subsets of the entries.

Abstract: A computer-based method for compressing varying-length columns of a non-leaf page high key generated during splitting of an index tree leaf page from a key pair including a last key of a splitting leaf page and a first key of a corresponding new leaf page. The method performs a logical comparison of the key pair by comparing each key pair corresponding columns' data with padding considered as insignificant. In a logically equal key pair with equal-length columns, the high key field will have the entire column data, and for unequal-length columns it will have column data of the shorter column length +1 byte and will have all remaining varying-length columns without trailing padding data. In a logically unequal key pair, the high key will have all columns up to and including a first differing byte, wherein the stored varying-length columns are stored without trailing padding data.

Abstract: A computer-based method for compressing varying-length columns of a non-leaf page high key generated during splitting of an index tree leaf page from a key pair including a last key of a splitting leaf page and a first key of a corresponding new leaf page. The method performs a logical comparison of the key pair by comparing each key pair corresponding columns' data with padding considered as insignificant. In a logically equal key pair with equal-length columns, the high key field will have the entire column data, and for unequal-length columns it will have column data of the shorter column length +1 byte and will have all remaining varying-length columns without trailing padding data. In a logically unequal key pair, the high key will have all columns up to and including a first differing byte, wherein the stored varying-length columns are stored without trailing padding data.

Abstract: One or more indexes are built on data (concurrent with manipulation of data) wherein the index build operation is done without restricting the manipulation of data. The index is brought to consistency with the data based upon processing recovery log records to simulate index manipulations during data insert, update, or delete operations.

Abstract: A method, apparatus and article of manufacture, implementing the method, for operating a database management system stores information in at least one entry. Each entry is associated with a row. At least one entry comprises one or more columns. At least one of the columns has a varying length. At least one entry comprises an offset array having one or more offsets associated with the columns having the varying length. In another aspect of the invention, a column extraction table is built and used, with the offset array, to access a specified column of an entry. Alternately, code is generated to access a specified column based on the offset array of an entry. In yet another aspect of the invention, a comparison table is built and used, with the offset array, to compare subsets of the entries.

Abstract: A method, system and program for accessing records in a database object, such as an index or table. A cursor is maintained that points to a start entry in the database object. The database object has rows and columns of values. A runtime component receives a command to return a kth entry in the object having column values that satisfy predicates in a query statement. The runtime component calls a manager component that accesses entries in the database object to return the kth entry in the object having column values that satisfy the predicates. The manager component moves the cursor through sequential entries in the database object, in either the forward or reverse direction, until a kth entry that satisfies the predicates from the start entry is reached. The manager component positions the cursor to an entry that is the kth entry that satisfies the predicates from the start entry and returns data from the kth entry pointed to by the cursor to the runtime component.

Abstract: Provided is a system, method, and program for performing a reverse scan of an index implemented as a tree of pages. Each leaf page includes one or more ordered index keys and previous and next pointers to the previous and next pages, respectively. The scan is searching for keys in the leaf pages that satisfy the search criteria. If a current index key is a first key on a current page, then a request is made for a conditional shared latch on a previous page prior to the current page. If the requested conditional shared latch is not granted, then the latch on the current page is released and a request is made for unconditional latches on the previous page and the current page. After receiving the latches on the previous and current pages, a determination is made of whether the current index key is on the current page if the current page was modified since the unconditional latch was requested. The current index key is located on the current page if the current index key is on the current page.

Abstract: Disclosed is a system, method, and program for searching a list of entries. Each entry is comprised of multiple fields. Each field in the entry may include one of a range of possible values for that field. If search criteria is provided for less than all of the fields, then multiple search keys will be generated such that each generated search key includes a search value for each field. The search value for each field for which there are no provided search criteria comprises one of the possible values for that field. A search operation is executed for each of the generated search keys to determine entries in the list that include field values that match the search values in the search key.

Abstract: Provided is a system, method, and program for performing a reverse scan of an index implemented as a tree of pages. Each leaf page includes one or more ordered index keys and previous and next pointers to the previous and next pages, respectively. The scan is searching for keys in the leaf pages that satisfy the search criteria. If a current index key is a first key on a current page, then a request is made for a conditional shared latch on a previous page prior to the current page. If the requested conditional shared latch is not granted, then the latch on the current page is released and a request is made for unconditional latches on the previous page and the current page. After receiving the latches on the previous and current pages, a determination is made of whether the current index key is on the current page if the current page was modified since the unconditional latch was requested. The current index key is located on the current page if the current index key is on the current page.

Abstract: A method, apparatus, and article of manufacture for a computer implemented technique for deferring large object access with intermediate results. A query is executed in a database stored on a data storage device connected to a computer. A control structure representing an expression in the query is generated. An intermediate result is generated by retrieving data for the query that is not represented by the control structure. Then, a result table is built using the processed intermediate result and the control structure.

Abstract: A method, apparatus, article of manufacture, and a memory structure for configuring a database management system to operate with multiple key versions is disclosed. The method comprises the steps of accessing key information comprising self-describing key data and an associated version indicator, generating key conversion/comparison information from the accessed key information, and storing the key conversion/comparison information in a memory accessible to the database management system. The apparatus comprises a means for performing the above-entitled operations, and the article of manufacture comprises a program storage device tangibly embodying instructions for performing the operations.

Abstract: A method, apparatus, article of manufacture, and a memory structure for configuring a database management system to operate with multiple key versions is disclosed. The method comprises the steps of storing first key information comprising a first key format and an associated version indicator, when a command altering the key format is accepted, storing altered key information comprising the altered key format and the incremented version indicator in the index page set, and storing altered key information in an index catalog. The apparatus comprises a means for performing the above-entitled operations, and the article of manufacture comprises a program storage device tangibly embodying instructions for performing the operations.