Database recovery and index rebuilds

• US 10,140,189 B2
• Filed: 04/28/2015
• Issued: 11/27/2018
• Est. Priority Date: 04/28/2015
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Fang, Min, Jin, Di, Shi, Zhen Yu, Slinger, Nigel G., Wang, Shu, Zheng, Li Fei, Zhu, Wen Jie
• Primary Examiner(s): Featherstone, Mark D
• Assistant Examiner(s): Forouharnejad, Faezeh
• Application Number:
  US14/697,794
• Publication Number:
  US 20160321142A1
• Time in Patent Office: 1,309 Days
• CPC Class Codes: G06F 11/1446 Point-in-time backing up or restoration of persistent data
• CPC Class Codes: G06F 11/1451 by selection of backup contents
• CPC Class Codes: G06F 11/1469 Backup restoration techniques
• CPC Class Codes: G06F 11/1471 involving logging of persistent data for recovery
• CPC Class Codes: G06F 11/1474 in transactions G06F16/20 takes precedence
• CPC Class Codes: G06F 16/2272 Management thereof
• CPC Class Codes: G06F 16/2358 Change logging, detection, and notification replication G06F16/27
• CPC Class Codes: G06F 2201/80 Database-specific techniques
• CPC Class Codes: G06F 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data

Abstract

A computer-implemented method for recovering data and concurrently rebuilding indexes for the recovered data in a database for a system configured to store fewer than all indexes in backup files may include copying data from one or more database files and storing the copied data to one or more backup files. A recovery manager executing on a processor may read the copied data from the one or more backup files and write the copied data to the one or more database files, wherein the data is recovered to the one or more database files. In response to the reading, an index manager executing on the processor may initiate a rebuilding of one or more indexes for the copied data at substantially the same time as the reading of the copied data.

Claims

1. A computer-implemented method for recovering data and concurrently rebuilding indexes for the recovered data in a database for a system configured to store fewer than all indexes in backup files, comprising:

copying data from one or more database files and storing the copied data to one or more backup files;

reading the copied data from the one or more backup files, by a recovery manager executing on a processor, and writing the copied data to the one or more database files by the recovery manager, wherein the data is recovered to the one or more database files, and wherein one or more indexes are not recovered;

in response to and at substantially the same time as the reading, initiating a rebuilding of the one or more indexes for the copied data, by an index manager executing on the processor, wherein initiating the rebuilding of the one or more indexes at substantially the same time reduces a quantity of 1/0 operations needed for data recovery; and

in response to finishing the rebuilding of the one or more indexes, applying a first set of log records from a transaction log to the one or more database files, the one or more log records specify a particular point in time for recovery.

2. The method of claim 1, wherein the storing of the copied data to one or more backup files includes storing an image copy of the data to a sparse backup file, and storing a log record of the data to a transaction log, the sparse backup file includes an empty pages of data and is not allocated disk space for the data at a first time, wherein in response to a page of the one or more database files being modified at a second subsequent time, a size of the sparse file expands such that the sparse backup file pages are no longer empty.

3. The method of claim 1, wherein initiating of the rebuilding of one or more indexes includes receiving one or more sorted index keys by the index manager, and rebuilding the one or more indexes in response to the receiving of the one or more sorted index keys.

4. The method of claim 1, wherein the rebuilding of the one or more indexes finishes at substantially the same time as the writing of the copied data.

5. The method of claim 1, wherein the reading the copied data from the one or more backup files by the recovery manager includes:

reading an image copy of one or more data pages of the copied data from a sparse backup file, the reading of the image copy further comprising;

parsing the one or more data pages from the image copy into one or more database records, extracting one or more index keys from the one or more database records, and sorting the one or more index keys in preparation initiating of the rebuilding of one or more indexes; and

reading one or more log records from a transaction log, wherein the one or more log records specify a particular point in time for recovery.

6. The method of claim 5, wherein the writing includes writing the image copy from the sparse backup file to the one or more database files and applying the one or more log records from the transaction log to the one or more database files.

7. The method of claim 6, wherein the reading of the image copy and the reading of the one or more log records is initiated at a first time, initiating of the rebuilding of one or more indexes occurs at a second time, and the applying of one or more log records is initiated at a third time, the third time being subsequent to the second time and the second time being subsequent to the first time.