Multiple-computer data processing system and method with time-versioned data storage

• US 6,725,242 B2
• Filed: 01/02/2001
• Issued: 04/20/2004
• Est. Priority Date: 02/11/2000
• Status: Expired due to Fees

• Current Assignee: Observatory House Windsor Road
• Original Assignee: Fujitsu Services Limited (Fujitsu Limited)
• Inventors: Gardner, Paul Anton Richardson
• Primary Examiner(s): Corrielus, Jean M.
• Assistant Examiner(s): Liang, Gwen
• Application Number:
  US09/752,985
• Publication Number:
  US 20030055805A1
• Time in Patent Office: 1,204 Days
• Field of Search: 707/203, 707/1, 707/8, 707/202, 714/20, 717/170
• US Class Current: 1/1
• CPC Class Codes: G06F 16/2322 using timestamps
• CPC Class Codes: G06F 16/2329 using versioning
• CPC Class Codes: G06F 16/2477 Temporal data queries
• CPC Class Codes: Y10S 707/99953 Recoverability
• CPC Class Codes: Y10S 707/99954 Version management

Abstract

A data processor comprises a number of databases for storing records and a plurality of user systems capable of accessing the databases. The user systems each include a datastore/application environment instance with which users can interface. Host systems may include more than one instance. The datastores contain time-versioned views of records. The data processor is operable in at least two modes, a normal operation mode in which an evaluation in response to a user enquiry can be carried out using records relevant to a current viewpoint time and time span, and a recovery operation mode in which records relevant to a viewpoint time and time span for a previous evaluation are accessed and used to exactly reproduce the previous evaluation.

Claims

1. A data processing apparatus comprising:

a plurality of user systems respectively including a plurality of object store instances, and at least one database accessible by said user systems, wherein the object store instances store time-versioned views of a plurality of objects as a plurality of records in said database, each of said records containing at least one attribute, a time span, a creation time, an object version marker, and a type field indicating whether said record is a concrete record or a delta record that modifies an attribute value of a previous record;

separate clocks for each of the object store instances;

means in each of the object store instances for performing an evaluation involving a particular object, relevant to a viewpoint time and time span; and

means in each of the object store instances for employing a creation time of a most recent version of said particular object in a calculation to determine whether a time adjustment is required and whether said evaluation should be re-run in view of non-synchronization of the object store instances'"'"' clocks and clock-skew between the object store instances.

2. A data processing apparatus as claimed in claim 1, wherein a most recent concrete record for each of said objects has an end time corresponding to a hypothetical maximum time, with no delta record corresponding to any part of its time span;

said data processing apparatus further including means for locking an object during updates to said object, using only said most recent concrete record for locking.

3. A data processing apparatus comprising:

a plurality of user systems respectively including a plurality of object store instances, and at least one database accessible by said user systems, wherein the object store instances store time-versioned views of a plurality of objects as a plurality of records in said database, each of said records containing at least one attribute, a time span, a creation time, and a type field indicating whether said record is a concrete record or a delta record;

means in each of the object store instances for accessing records relevant to a particular viewpoint time and time span; and

recovery supporting means in each of the object store instances for storing a most recently used viewpoint time and time span together with a commit time as an instance of a session object, for linking the session object to an object identifying an object store instance, and for adding the session object to a relevant atomic unit.

4. A data processing method for use in a data processing system comprising at least one database and a plurality of user systems, the database being accessible by said user systems, and the user systems respectively including a plurality of object store instances having separate clocks, the method including:

storing time-versioned views of a plurality of objects as a plurality of records in said database, each of said records containing at least one attribute, a time span, a creation time, an object version marker, and a type field indicating whether said record is a concrete record or a delta record that modifies an attribute value of a previous record;

performing an evaluation involving a particular object, relevant to a viewpoint time and time span; and

employing a creation time of a most recent version of said particular object in a calculation to determine whether a time adjustment is required and whether said evaluation should be re-run in view of non-synchronization of the object store instances'"'"' clocks and clock-skew between the object store instances.

5. A data processing method as claimed in claim 4, wherein a most recent concrete record for each of said objects has an end time corresponding to a hypothetical maximum time, with no delta record corresponding to any part of its time span, the method further including locking an object during updates to said object, using only said most recent concrete record for locking.

6. A data processing method for use in a data processing system comprising at least one database and a plurality of user systems, the database being accessible by said user systems, and the user systems respectively including a plurality of object store instances, the method including:

storing time-versioned views of a plurality of objects as a plurality of records in said database, each of said records containing at least one attribute, a time span, a creation time, and a type field indicating whether said record is a concrete record or a delta record;

accessing records relevant to a particular viewpoint time and time span; and

supporting recovery by storing a most recently used viewpoint time and time span together with a commit time as an instance of a session object, linking the session object to an object identifying a particular object store instance, and adding the session object to a relevant atomic unit.