Abstract: A system and method for managing and storing logically grouped hierarchical data via physical block storage is provided. Logical groups of parsed XML node data forming node ID ranges are indexed by creating and inserting an index entry into a node ID range. Index entries indicate node ID range bounds for blocks in which nodes are stored. Consulting a node ID range index facilitates XML node traversal via logical links between nodes in different blocks. Additionally, physical links between nodes within a block allow for fast node traversal. Node update including insertion and deletion as well as document order based pre-fetch and XML document re-organization is also facilitated by this architecture.

Abstract: An extensible identification system for nodes in a hierarchy is described wherein each node is assigned a concatenation of decimal based values. The values assigned uniquely identify the node, provides an order for the node, and identifies its parent, child, and sibling relationships with other nodes Furthermore, the IDs assigned can be encoded to be byte comparable. Furthermore, the ID's assigned to nodes need not be modified when changes (adding/deleting a child node or a subtree of nodes) are made in the hierarchy. Additionally, in the event of such a change, the order and relationships between the parent, child, and sibling nodes are retained.

Abstract: A method (and an article of manufacture having computer readable program code to implement the method) is disclosed to version a node range and locate a versioned node range in a storage architecture, wherein the method comprises: maintaining a set of node ranges, with each node range being formed from a range of node ID values assigned to each node among a plurality of nodes, receiving a node modification request for a node range from a database system, versioning the node range by copying (to a storage) a node range to which the node modification request is to be made, labeling the copied node range with a timestamp, locating the labeled node range via the timestamp and a hash on the node range, and outputting the located labeled node range. Optionally, versioning is done by shadowing nodes in the range to a version hash table based on a range identifier.

Abstract: A method and system for distributed garbage collection in a pipelined workflow environment comprising a plurality of processing nodes that pass item references to each other. Each node maintains a reference list of local item references and a reference dictionary of remote item references, and periodically synchronizes the reference list with the reference dictionaries of other nodes in the workflow, so that item references are not marked for garbage collection while other processing nodes may still have outstanding references to them.

Abstract: Method for ordering nodes within hierarchical data. The concept of isolated ordered regions to maintain coordinates of nodes is used by associating each node with coordinates relative to a containing region. Modifications to nodes within a region only affect the nodes in that region, and not nodes in other regions. Traversals that retrieve information from the nodes can rebase the coordinates from their containing region and return with a total order.

Abstract: Method for ordering nodes within hierarchical data. The concept of isolated ordered regions to maintain coordinates of nodes is used by associating each node with coordinates relative to a containing region. Modifications to nodes within a region only affect the nodes in that region, and not nodes in other regions. Traversals that retrieve information from the nodes can rebase the coordinates from their containing region and return with a total order.

Abstract: A method and system for distributed garbage collection in a pipelined workflow environment comprising a plurality of processing nodes that pass item references to each other. Each node maintains a reference list of local item references and a reference dictionary of remote item references, and periodically synchronizes the reference list with the reference dictionaries of other nodes in the workflow, so that item references are not marked for garbage collection while other processing nodes may still have outstanding references to them.

Abstract: A method and apparatus is disclosed for XML query evaluation using early-outs and multiple passes to evaluate an XML query. A multi-pass evaluation procedure evaluates the XML query one step at a time as needed to complete evaluation. The multi-pass evaluation procedure evaluates XML queries containing logical expressions such as “AND” expressions, “OR” expressions, and implied “AND” expressions within “FOR” clauses. Queries containing logical expressions are often satisfied before every component is evaluated. Thus, executing the multi-pass evaluation procedure allows the evaluation to exit early when the veracity of the query is determined, not necessarily when every component has been evaluated. The multi-pass evaluation procedure executes as long as a descendant axis of the XML query need not be evaluated past a child node. When evaluation of a descendant axis past a child node is required, the multi-pass evaluation procedure may switch to a single-pass evaluation procedure to complete evaluation.

Abstract: An apparatus and method for handling a LET binding used in a WHERE clause of an XQuery FLWOR expression during an XML pivot join procedure. XPath steps under a LET binding are identified and marked as bindings. During a match graph construction phase of the pivot join procedure, the bindings are linked to a first common non-LET binding ancestor, while traversing from the bottom up. A location identifier for each binding is truncated to the location identifier of the first common non-LET binding ancestor to create a truncated location identifier. The truncated location identifier is compared to a node identification of a FOR binding of the XQuery FLWOR expression. A match of the node identifications will qualify the XML document and the XML document is returned by the XML pivot join procedure.

Abstract: An apparatus and method for handling a LET binding used in a WHERE clause of an XQuery FLWOR expression during an XML pivot join procedure. The disclosed apparatus and method enable an XML pivot join procedure to accurately process a query and return one or more qualifying documents. A logical expression within the WHERE clause is identified. Next steps of the logical expression are separated by logical operators. The LET binding is incorporated with each next step. The XQuery FLWOR expression is rewritten using the incorporations along with a FOR binding of the XQuery FLWOR expression to make a syntactically equivalent XPath query. Predicates of the LET binding may also be incorporated with the next steps, without altering the predicates.

Abstract: Method for ordering nodes within hierarchical data. The concept of isolated ordered regions to maintain coordinates of nodes is used by associating each node with coordinates relative to a containing region. Modifications to nodes within a region only affect the nodes in that region, and not nodes in other regions. Traversals that retrieve information from the nodes can rebase the coordinates from their containing region and return with a total order.

Abstract: An apparatus and method are disclosed for skipping XML index scans with common ancestors of a previously failed predicate. An XML index is scanned by an XML index scan to filter entries of the index matching at least one search value (predicate) of an XML query. When the XML index scan finds a matching entry, the entry is passed to an XPath evaluation component. The XPath evaluation component evaluates the entry against remaining predicates of the XML query for further qualification. When the XPath evaluation component disqualifies an entry, the XPath evaluation component provides feedback to the XML index scan to skip remaining entries comprising a common ancestor of the disqualified entry's path. The XML index scan can then efficiently skip index entries that will not qualify against the XML query.

Abstract: An apparatus and method are disclosed for finding and returning sub-trees from within a preselected XML document that match an XQuery FLWOR expression having a binding order, in which a match graph is generated from an XML index of node paths for a collection of XML documents, where the collection includes the preselected XML document and the match graph is first traversed by a plurality of cursors in a reverse binding order and traversed by the plurality of cursors in forward binding order.

Abstract: An apparatus and method are disclosed for handling a LET binding used in a WHERE clause of an XQuery FLWOR expression during an XML pivot join procedure. The disclosed apparatus and method enable an XML pivot join procedure to accurately process a query and return one or more qualifying document. A logical expression within the WHERE clause is identified. Next steps of the logical expression are separated by logical operators. The LET binding is incorporated with each next step. The XQuery FLWOR expression is rewritten using the incorporations along with a FOR binding of the XQuery FLWOR expression to make a syntactically equivalent XPath query. Predicates of the LET binding may also be incorporated with the next steps, without altering the predicates.

Abstract: An apparatus and method are disclosed for handling a LET binding used in a WHERE clause of an XQuery FLWOR expression during an XML pivot join procedure. XPath steps under a LET binding are identified and marked as bindings. During a match graph construction phase of the pivot join procedure, the bindings are linked to a first common non-LET binding ancestor, while traversing from the bottom up. A location identifier for each binding is truncated to the location identifier of the first common non-LET binding ancestor to create a truncated location identifier. The truncated location identifier is compared to a node identification of a FOR binding of the XQuery FLWOR expression. A match of the node identifications will qualify the XML document and the XML document is returned by the XML pivot join procedure.

Abstract: A method and apparatus is disclosed for XML query evaluation using early-outs and multiple passes to evaluate an XML query. A multi-pass evaluation procedure evaluates the XML query one step at a time as needed to complete evaluation. The multi-pass evaluation procedure evaluates XML queries containing logical expressions such as “AND” expressions, “OR” expressions, and implied “AND” expressions within “FOR” clauses. Queries containing logical expressions are often satisfied before every component is evaluated. Thus, executing the multi-pass evaluation procedure allows the evaluation to exit early when the veracity of the query is determined, not necessarily when every component has been evaluated. The multi-pass evaluation procedure executes as long as a descendant axis of the XML query need not be evaluated past a child node. When evaluation of a descendant axis past a child node is required, the multi-pass evaluation procedure may switch to a single-pass evaluation procedure to complete evaluation.

Abstract: An apparatus and method are disclosed for skipping XML index scans with common ancestors of a previously failed predicate. An XML index is scanned by an XML index scan to filter entries of the index matching at least one search value (predicate) of an XML query. When the XML index scan finds a matching entry, the entry is passed to an XPath evaluation component. The XPath evaluation component evaluates the entry against remaining predicates of the XML query for further qualification. When the XPath evaluation component disqualifies an entry, the XPath evaluation component provides feedback to the XML index scan to skip remaining entries comprising a common ancestor of the disqualified entry's path. The XML index scan can then efficiently skip index entries that will not qualify against the XML query.

Abstract: The concept of isolated ordered regions to maintain coordinates of nodes is used by associating each node with coordinates relative to a containing region. Modifications to nodes within a region only affect the nodes in that region, and not nodes in other regions. Traversals that retrieve information from the nodes can rebase the coordinates from their containing region and return with a total order. Access patterns and usage are used to recognize and prefetch pages. The probability of revisiting traversed nodes are identified and pages in a bufferpool are replaced based upon the identified probabilities (e.g., replacing pages with the least probability of a revisit).