US5524205A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Methods and apparatus for optimizing undo log usage
Assignee: Oracle International Corp
•
Filing: 1993-04-21
•
Granted: 1996-06-04
•
Expires: 2013-04-21
Abstract
Abstract Each node in a data processing system contains at least one undo buffer and one least one redo buffer for insuring that any changes made to a section of a non-volatile storage medium, such as a disk, can be removed, if a transaction has not been committed, or can be recreated if the transaction has not been committed. The undo buffers each correspond to a different uncommitted transaction. The redo buffer contains the changes made to a copy of the section which is maintained in the memory.
Inventors
- 👤 David B. Lomet
- 👤 Peter M. Spiro
- 👤 Ashok M. Joshi
- 👤 Ananth Raghavan
- 👤 Tirumanjanam K. Rengarajan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:54
CPC Classifications
G; G06; G06F; G06F12/00; G06F12/16; G06F11/00; G06F11/07; G06F11/14; G06F11/1471; G06F2201/00; G06F2201/87
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
139 words
A data processing recovery apparatus comprising: a redo buffer containing a set of redo records, said redo buffer including information for committed and uncommitted transactions; an undo buffer containing a set of undo records, said undo buffer including information only for an uncommitted transaction, said undo records being aggregated in said undo buffer separately from said redo records in said redo buffer; and a log management routine for starting an uncommitted transaction, recording redo records corresponding to said uncommitted transaction in said redo buffer, recording undo records for said uncommitted transaction in said undo buffer, committing said transaction, storing said redo records corresponding to said committed transaction from said redo buffer to persistent storage, and for separately discarding said undo records corresponding to said committed transaction from said undo buffer while retaining said redo records in said redo buffer.
Claim 2
Dependent Claim
139 words
A data processing recovery apparatus comprising: a redo buffer containing a set of redo records, said redo buffer including information for committed and uncommitted transactions; an undo buffer containing a set of undo records, said undo buffer including information only for an uncommitted transaction, said undo records being aggregated in said undo buffer separately from said redo records in said redo buffer; and a log management routine for starting an uncommitted transaction, recording redo records corresponding to said uncommitted transaction in said redo buffer, recording undo records for said uncommitted transaction in said undo buffer, committing said transaction, storing said redo records corresponding to said committed transaction from said redo buffer to persistent storage, and for separately discarding said undo records corresponding to said committed transaction from said undo buffer while retaining said redo records in said redo buffer.
Claim 3
Dependent Claim
31 words
The data processing recovery apparatus as claimed in claim 1 further including an active transactions table stored in a memory and containing entries corresponding to transactions which have not been committed.
Claim 4
Dependent Claim
34 words
The data processing recovery apparatus as claimed in claim 2 further including a means for removing from said active transactions table an entry corresponding to a first transaction after said first transaction is committed.
Claim 5
Dependent Claim
34 words
The data processing recovery apparatus as claimed in claim 2 further including a means for storing the contents of said undo buffer in said persistent storage prior to storing changes from corresponding uncommitted transactions.
Claim 6
Independent Claim
138 words
A method for data processing recovery comprising the steps of: providing a redo buffer containing a set of redo records, said redo buffer including information for committed and uncommitted transactions; providing an undo buffer containing a set of undo records, said undo buffer including information only for an uncommitted transaction, said undo records being aggregated in said undo buffer separately from said redo records in said redo buffer; starting an uncommitted transaction; recording redo records corresponding to said uncommitted transaction in said redo buffer; recording undo records for said uncommitted transaction in said undo buffer; committing said transaction; storing said redo records corresponding to said committed transaction from said redo buffer to persistent storage; and separately discarding said undo records corresponding to said committed transaction from said undo buffer while retaining said redo records in said redo buffer.
Claim 7
Independent Claim
138 words
A method for data processing recovery comprising the steps of: providing a redo buffer containing a set of redo records, said redo buffer including information for committed and uncommitted transactions; providing an undo buffer containing a set of undo records, said undo buffer including information only for an uncommitted transaction, said undo records being aggregated in said undo buffer separately from said redo records in said redo buffer; starting an uncommitted transaction; recording redo records corresponding to said uncommitted transaction in said redo buffer; recording undo records for said uncommitted transaction in said undo buffer; committing said transaction; storing said redo records corresponding to said committed transaction from said redo buffer to persistent storage; and separately discarding said undo records corresponding to said committed transaction from said undo buffer while retaining said redo records in said redo buffer.
Claim 8
Dependent Claim
32 words
The method as claimed in claim 5 further including the step of providing an active transactions table stored in a memory and containing entries corresponding to transactions which have not been committed.
Claim 9
Dependent Claim
31 words
The method as claimed in claim 6 further including the step of removing from said active transactions table an entry corresponding to a first transaction after said first transaction is committed.
References Cited (Backward Citations)
US4507751A
Cited
US4498145A
Cited
US4686620A
Cited
US4751702A
Cited
US4868744A
Cited
US4878167A
Cited
US4853843A
Cited
US4945474A
Cited
US5043866A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-06-04 | 1999-12-04 | 2000-06-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-06-04 | 2003-12-04 | 2004-06-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-06-04 | 2007-12-04 | 2008-06-04 | $7700.00 | Window Closed / Lapsed |