Abstract: Database system and methods are described for improving scalability of multi-user database systems by improving management of locks used in the system. The system provides multiple server engines, with each engine having a Parallel Lock Manager. More particularly, the Lock Manager decomposes the single spin lock traditionally employed to protect shared, global Lock Manager structures into multiple spin locks, each protecting individual hash buckets or groups of hash buckets which index into particular members of those structures. In this manner, contention for shared, global Lock Manager data structures is reduced, thereby improving the system's scalability. Further, improved "deadlock" searching methodology is provided. Specifically, the system provides a "deferred" mode of deadlock detection. Here, a task simply goes to sleep on a lock; it does not initiate a deadlock search. At a later point in time, the task is awakened to carry out the deadlock search.

Abstract: Database system and methods are described for improving execution speed of database queries (e.g., for transaction processing and for decision support) by optimizing use of buffer caches. The system includes an Optimizer for formulating an optimal strategy for a given query. More particularly, the Optimizer communicates with a Buffer Manager before it formulates the query plan. For instance, the Optimizer may query the Buffer Manager for the purpose of determining whether the object of interest (e.g., table or index to be scanned) exists in its own buffer cache (i.e., whether it has been bound to a particular named cache). If the object exists in its own cache, the Optimizer may inquire as to how much of the cache (i.e., how much memory) the object requires, together with the optimal I/O size for the cache (e.g., 16K blocks). Based on this information, the Optimizer formulates a query strategy or plan with "hints," which are ultimately passed to the Cache or Buffer Manager.

Abstract: Database system and methods are described for improving execution speed of database queries (e.g., for transaction processing and for decision support) by optimizing use of buffer caches. The system includes an Optimizer for formulating an optimal strategy for a given query. More particularly, the Optimizer communicates with a Buffer Manager before it formulates the query plan. For instance, the Optimizer may query the Buffer Manager for the purpose of determining whether the object of interest (e.g., table or index to be scanned) exists in its own buffer cache (i.e., whether it has been bound to a particular named cache). If the object exists in its own cache, the Optimizer may inquire as to how much of the cache (i.e., how much memory) the object requires, together with the optimal I/O size for the cache (e.g., 16K blocks). Based on this information, the Optimizer formulates a query strategy or plan with "hints," which are ultimately passed to the Cache or Buffer Manager.

Abstract: A Client/Server Database System with improved methods for performing database queries, particularly DSS-type queries, is described. The system includes one or more Clients (e.g., Terminals or PCs) connected via a Network to a Server. In general operation, Clients store data in and retrieve data from one or more database tables resident on the Server by submitting SQL commands, some of which specify "queries"--criteria for selecting particular records of a table. The system implements methods for storing data vertically (i.e., by column), instead of horizontally (i.e., by row) as is traditionally done. Each column comprises a plurality of "cells" (i.e., column value for a record), which are arranged on a data page in a contiguous fashion. By storing data in a column-wise basis, the system can process a DSS query by bringing in only those columns of data which are of interest.

Abstract: A Client/Server Database System with improved methods for performing database queries, particularly DSS-type queries, is described. The system includes one or more Clients (e.g., Terminals or PCs) connected via a Network to a Server. In general operation, Clients store data in and retrieve data from one or more database tables resident on the Server by submitting SQL commands, some of which specify "queries"--criteria for selecting particular records of a table. The system implements methods for storing data vertically (i.e., by column), instead of horizontally (i.e., by row) as is traditionally done. Each column comprises a plurality of "cells" (i.e., column value for a record), which are arranged on a data page in a contiguous fashion. By storing data in a column-wise basis, the system can process a DSS query by bringing in only those columns of data which are of interest.

Abstract: A system providing improved National Language Support (NLS) in application programs is described. The system employs normalized Unicode data with generic transformation structures having locale overlays. Methods are described for navigating the structures during system operation, for effecting various transformation processes using locale-specific information. The locale-specific information is maintained in the structures as external data files. Since the data files are read in at runtime, the underlying binary files which comprise the program need not be modified for updating the program to support a new locale. The approach provides extensibility to applications with National Language Support. Additionally, increased portability is provided, since manipulation of the underlying data remains unchanged regardless of the underlying platform. Program maintenance is also decreased, since engineers need only maintain a single core.

Abstract: A system providing improved National Language Support (NLS) in application programs is described. The system employs normalized Unicode data with generic transformation structures having locale overlays. Methods are described for navigating the structures during system operation, for effecting various transformation processes using locale-specific information. The locale-specific information is maintained in the structures as external data files. Since the data files are read in at runtime, the underlying binary files which comprise the program need not be modified for updating the program to support a new locale. The approach provides extensibility to applications with National Language Support. Additionally, increased portability is provided, since manipulation of the underlying data remains unchanged regardless of the underlying platform. Program maintenance is also decreased, since engineers need only maintain a single core.

Abstract: An Interactive Television (ITV) Client/Server system comprises one or more Clients (e.g., set top boxes or "STBs") connected to a Server module, via a Broadband Communication Network, is described. The system provides a generic mechanism for deciding how much or how little data is to be sent in response to a request from a Client. Specifically, each Client is allowed to describe ahead of time how much memory (approximately or exactly) it is allowing for the query result. This is communicated by the Client as part of the query itself. Regardless of what other activity the Client undertakes, the server maintains the context of the original query, until the Client terminates the connection. In a similar manner, when other simultaneous queries are open, the context is maintained for each query until the connection is dropped (or the query terminates). The Client can ask for more data (i.e., rows) on any open query. To optimize operation of the environment, requests from the Clients (i.e.

Abstract: A method for ensuring reliable interactions between principals within a database or between databases. The method involves the creation of database contracts which are, in essence, binding constraints on the behavior of entities within a database system that can be enforced by the system. A database contract is formed when two or more principals agree on the terms and conditions of the contract, and a monitor puts in to place the constraints necessary to enforce the agreed-upon terms and conditions after determining that each of the principals has the requisite authority and ability to carry out the contract.

Abstract: Video system and methods are described for improved image processing (e.g., anti-aliasing) of digital images. The video system includes a shift register component interposed (operably) between video memory and video digital-to-analog components. In this fashion, the shift register stores, at any given time, a collection of pixel values which have been scanned (read) out of the video memory. The shift register is adapted so that a neighborhood of pixel values is available at a given instance for a current pixel from the image stored in the video memory. Selected cells of the shift register are adapted to include "taps" which form connections between those cells and the input to a multiplier/adder circuit. Once a given neighborhood of pixel values is supplied to the multiplier/adder circuit, the system may compute a new (i.e., enhanced) pixel value by applying a filter template--a collection of filter weightings or coefficients.

Abstract: A Client/Server Database System with improved methods for appending items to an object, such as appending data records to a database table, in the context of a multi-user environment is described. The system includes one or more Clients (e.g., Terminals or PCs) connected via a Network to a Server. The Clients store data in and retrieve data from one or more database tables resident on the Server by submitting SQL commands, some of which specify insert or append operations, for appending records to a table. For enhancing the speed in which multiple appenders (i.e., Clients) can append records, the operation of the server is modified to store an object (e.g., table) as multiple (physical) page chains. From the logical viewpoint, a single (logical) page chain of data pages is presented to each client or user. From the perspective of inserting records, however, the system has multiple page chains to insert into, thereby removing contention among multiple appenders for the last page.

Abstract: Method and arrangement for dispatching messages between instance specific dispatch tables of objects, when a particular object does not have resident the method called for execution in response to a message directed toward it. When a message is sent to a first object and the method called for execution is not resident or associated with the first object, the first object may expressly reference another object of the same class which may contain the required method. The message is according dispatched to another instance specific dispatch table associated with an object which may be able to execute the method called for by the message initially transmitted. Upward chaining between instance, class, and superclass level dispatch tables, and method supercalls canceling the effect of method overriding by instance level methods are included in the method and arrangement.

Abstract: Method and system for distributing prefragmented data processing loads in a fault tolerant system linked in a ring topology of disk subsystems and data processing nodes. The data processing load of the node under fault is shifted in one direction along the ring, and adjacent nodes in the same direction along the ring successively shift their entire data processing loads to their immediately adjacent data processing nodes. The adjacent data processing nodes in the non-shifted direction absorb increased workloads by one net data fragment each. Each successive data processing node away from the node under fault absorbs an increasing number of data fragments from its adjacent data processing node until the entire data processing load of an adjacent data processing node is absorbed.

Abstract: A novel method of and system for heterogeneous connectivity and universal and generic interfacing for distributed applications and processes residing in a wide variety of computing platforms communicating over varied transport facilities, through an integrated set of lower-level programs and routines that handle specific services (message/data recovery, security, directory services, etc.) available from applications and processes within varied complex computing and communications environments, and without having to deal with the idiosyncrasies of differing networks, protocols, devices, multiple "standards", routing, recovery and other transport difficulties and differences.

Abstract: Computer systems and computer implemented methods are provided for managing memory in a database management system. The computer memory is partitioned into a plurality of buffer caches, each of which is separately addressable. One buffer cache is set aside as a default buffer cache, while the other buffer caches are reserved for specific data objects meeting certain predefined criteria. Those objects meeting the predefined criteria are stored in reserved buffer caches where they are likely to remain for a relatively long period of time (in comparison to data objects stored in the default buffer caches). A buffer cache may have a plurality of memory pools, each of which contains multiple storage blocks. The storage blocks in a given memory pool are identically sized, while the storage blocks in one memory pool are sized differently from the storage blocks in another memory pool.

Abstract: A data backup system implements coordination between a Database Server and a Backup Server to produce a recoverable database dump. By utilizing a technique referred to as stripe affinity, a mechanism is disclosed for ensuring the integrity of a database backup made to multiple archive devices simultaneously. In addition, by utilizing stripe affinity, archived data may be reloaded from fewer archive devices than were used to make the original backup.A task scheduler mechanism allocates processor time among the tasks that comprise the backup system. In this way the I/O service tasks can process their event queues while the current set of allocation pages are also being processed.

Abstract: Database system and methods are described for improving execution speed of database queries (e.g., for decision support) by optimizing execution of nested queries or "subqueries," such as are commonly used in client/server database environments. In particular, a subquery cache is provided having a size which can be dynamically adjusted by the system during execution of the query, for achieving an optimal cache size. During execution of the subquery, the system keeps statistics on cache "hits" and "misses." Specifically, the system stores a count of the number of times a row is found in the cache (i.e., a "hit") as well as a count of the number of times a scan of the cache yields no "hit" (i.e., a "miss"). Also, a maximum LRU (least-recently used) depth of the deepest hit in the cache is also tracked. This tracks how deep (i.e., the deepest row) into the cache there has been a "hit.

Abstract: A server performs an indexing method of data management to create and maintain indexes more efficiently than existing indexing approaches. The server is disposed between an application program and a DBMS and is coupled to a data base located within the DBMS. The data base has an ordered set of data values stored in memory. Each data value has a bit pattern and an identifier associated therewith. The server creates a plurality of bit vectors such that the number of bit vectors created equals the longest length bit pattern for the values. The server accesses one of the values stored in the data base. Each bit of the bit pattern for the value is then assigned by the server to a unique position in successive bit vectors. The bits are assigned to identical unique positions in each of the successive bit vectors. The server repeats the above-described accessing and assigning steps for each remaining value of the set to form an index of bit vectors for the values.

Abstract: Database system and methods are described for maintenance of B-Tree indexes, such as are commonly used in a relational database environment. "Load patterns" are monitored, for optimizing B-Tree node splitting, based on a particular load pattern's effect on B-Tree growth. More particularly, an "ascending insert" load pattern--that is, the insertion of data records for a multi-column table where the particular records to be inserted have a fixed value for the first column and a monotonically increasing value for the subsequent column(s)--can be identified and optimized. Methods are described for splitting the B-Tree nodes or pages, not at the half-way point, but instead exactly at the point of insertion, a position where the insert row would have gone into the page (had it not overflowed).

Abstract: Method and arrangement for dynamic, run-time alteration of pre-set variable space relationships by run-time GUI modification of object connections associated with the variable spaces. Arbitrary linkages between all variable spaces are established prior to runtime to allow initial conditions for variable resolution irrespective of anticipated or actual object connections. Thus all variables associated with objects are prespecified and provided with initial values, so long as a value has been assigned to the variable in some object. When actual object relationships are indicated at run-time, these effect new variable space linkages. The initial and subsequent linkages are effected with pointer addresses within the respective variable spaces.