EP0672984A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Transaction processing system and method
Assignee: International Business Machines Corp
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Filing: 1995-01-26
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Granted: —
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Expires: 2015-01-26
Abstract
Abstract A transaction processing system that continues to process incoming transactions during the failure and recovery of either of two duplicate databases. One of the two duplicate databases is assigned "active" status and the other is maintained with "redundant" status. All incoming queries are sent only to the active database and all incoming updates are sent to both active and redundant databases. When one database fails, the other is immediately reassigned active status if not already active and continues to process incoming queries and updates during the failure. When the failed database is repaired and restarted, all records are flushed therefrom and the failed database is reconstructed using interleaved copy and update operations in a single pass through the active database. Incoming transaction and copy operations are interleaved according to a queue thresholding method for throttling copy operations responsive to increased numbers of incoming transactions. The transaction processing system remains operational both during the failure and during the recovery activities and reaches full recovery without downtime.
Inventors
- 👤 Wayne Charles Carlson
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 01:21
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/07; G06F11/16; G06F11/20; G06F11/2053; G06F11/2056; G06F11/2082; G06F11/14; G06F11/1402; G06F11/1405; G06F11/141; G06F11/2064; Y; Y10; Y10S; Y10S707/00; Y10S707/99951; Y10S707/99952; Y10S707/99953
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
108 words
A transaction processing method for recovering from failure a second data base, stored in a second data base system, using a first data base, stored in a first data base system, which is a replica of said second data base, said method comprising the steps of: (a) constructing said second database system database by performing the interleaved steps of (a.1) processing in both said first and said second database system each said update as it occurs and processing only in said first database system each said query as it occurs, and (a.2) copying each said record from said first database system database to said second database system database.
Claim 2
Dependent Claim
84 words
The method of claim 1 wherein said copying step comprises the steps of: and (a.2.2) performing once for each said record the steps of (a.2.2.1) locking said each record in said first database system database to prevent changes resulting from concurrent performance of said processing step (a.1), (a.2.2.2) reading said each locked record in said first database system database, (a.2.2.3) inserting said each locked record into said second database system database, and (a.2.2.4) unlocking said each locked record in said first database system database.
Claim 3
Independent Claim
32 words
The method as claimed in either of claims 1 or 2 wherein said copying step (a.2) is performed for each said record in a single pass through said first database system database.
Claim 4
Independent Claim
80 words
The method as claimed in any preceding claim wherein said constructing step (a) further comprises the steps of: (a.3) ignoring in said second database system each said update requiring the deletion or change of a record that is not already represented by a record in said second database system database; and (a.4) ignoring in said second database system each said update requiring the insertion of a record that is already represented by a record in said second database system database.
Claim 5
Independent Claim
37 words
A method as claimed in any preceding claim, wherein each record has a unique record identification key and wherein said step of copying further comprises the steps of (a.2.1) ordering said records according to an ordering rule.
Claim 6
Independent Claim
39 words
A method as claimed in any preceding claim, further comprising, before the step of constructing, the steps of repairing said failure and restarting operation of said second database system; deleting all said records from said second database system database.
Claim 7
Dependent Claim
174 words
A transaction processing system for recovering from failure of a second database, stored in a second data base system, using a first database, stored in a first data base system, which is a replica of said active data base, comprising: input means for accepting queries and updates; said first database system means coupled to said input means for processing said queries and updates as they are accepted; said second database system means coupled to said input means for processing said updates concurrently with the operation of said first database system means; an first database in said first database system means for storing a plurality of records each having a unique Record Identification Key (RIK); a second database in said second database system means for storing a plurality of said records wherein said second database is a replica of said first database; and concurrent recovery means coupled to said first database system means and to said second database system means for recreating said second database concurrently with continuing operation of said first database system means.
Claim 8
Dependent Claim
61 words
The system of claim 7 further comprising: database clearing means in said concurrent recovery means for deleting all records from said second database concurrently with operation of said first database system means; and record copying means in said concurrent recovery means for copying records from said first database to said second database concurrently with operation of said first database system means.
Claim 9
Dependent Claim
68 words
The system as claimed in claim 8 wherein said record copying means comprises: locking means for locking at least one said record in said first database to prevent changes resulting from concurrent performance of said updates by said first database system means; reading means for reading said locked record in said first database; and insertion means for inserting a copy of said locked record into said second database.
Claim 10
Dependent Claim
60 words
The system as claimed in any of claim 6 to 9 further comprising: reassignment means coupled to said first database system means and to said second database system means for reassigning said queries to said second database system means responsive to failure of said first database system means, whereby said second database system means becomes the first database system means.
Claim 11
Independent Claim
60 words
The system as claimed in any of claims 6 to 10 wherein said concurrent recovery means comprises: error bypass means for ignoring each said update that either inserts a record that is already represented by a record present in said second database or changes or deletes a record that is not already represented by a record in said second database.
References Cited (Backward Citations)
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