Optimizing search for insert-only databases and write-once data storage

• US 8,301,610 B2
• Filed: 07/21/2010
• Issued: 10/30/2012
• Est. Priority Date: 07/21/2010
• Status: Active Grant

• Current Assignee: SAP SE
• Original Assignee: SAP AG (SAP SE)
• Inventors: Driesen, Volker, Eberlein, Peter
• Primary Examiner(s): DANG, THANH HA T
• Application Number:
  US12/840,719
• Publication Number:
  US 20120023125A1
• Time in Patent Office: 832 Days
• Field of Search: 707/705, 707/706, 707/769
• US Class Current: 707/705
• CPC Class Codes: G06F 16/24557 Efficient disk access during query execution
• CPC Class Codes: G06F 16/2477 Temporal data queries

Abstract

A search of an insert-only database is performed using a search string in a non-key field to obtain a result set having both valid and invalid entries. Each entry includes a primary key field and the primary key field is subsequently scanned for entries in the result set to determine which entries are valid. Thereafter, invalid entries are removed from the result set to result in a modified result set. Such removal can be based, for example, on the timestamp of the respective entries. In some implementations, a secondary persistence is utilized. Related apparatus, systems, techniques and articles are also described.

Claims

1. A method comprising:

performing, by at least one processor, a search of an insert-only database using a search string to obtain a result set having both valid and invalid entries, each entry in the insert-only database having an associated timestamp, the valid entries having a most recent timestamp and the invalid entries each having an earlier timestamp than a subsequent corresponding valid entry, wherein modification of at least one field in an entry in the insert-only database results in a corresponding entry being saved in a secondary data storage that comprises information characterizing the entry in the insert-only database including the timestamp for the entry;

scanning, by at least one processor, primary key fields of entries in the secondary data storage corresponding to the entries in the result set to determine which entries are valid based on their timestamps; and

removing, by at least one processor, invalid entries from the result set to result in a modified result set.

2. The method of claim 1, wherein the search uses a search string in a non-key field.

3. The method of claim 1, further comprising:

promoting, by at least one processor, the modified result set.

4. The method of claim 1, wherein promoting the modified result set comprises storing the modified result set.

5. The method of claim 1, wherein promoting the modified result set comprises transmitting the modified result set to a remote server.

6. The method of claim 1, wherein promoting the modified result set comprises visually displaying at least a portion of the modified result set.

7. The method of claim 1, wherein most recent entries as defined by the timestamps are scanned first such that, when a match is identified, older entries are removed from the result set.

8. A method for implementation by one or more data processors comprising:

performing, by at least one processor, a search of a write-once primary data storage using a search string to obtain a result set having both valid and invalid entries, each entry in the primary data storage having an associated timestamp, the valid entries having a most recent timestamp and the invalid entries each having an earlier timestamp than a subsequent corresponding valid entry, wherein modification of at least one field in an entry in the primary data storage results in a corresponding entry being saved in a secondary data storage that comprises information characterizing the entry in the primary data storage including the timestamp for the entry;

scanning, by at least one processor, primary key fields of entries in the secondary data storage corresponding to the entries in the result set to determine which entries are valid based on their timestamps; and

removing, by at least one processor, invalid entries from the result set to result in a modified result set.

9. The method of claim 8, wherein the search uses a search string in a non-key field.

10. The method of claim 8, further comprising:

promoting, by at least one processor, the modified result set.

11. The method of claim 8, wherein promoting the modified result set comprises storing the modified result set.

12. The method of claim 8, wherein promoting the modified result set comprises transmitting the modified result set to a remote server.

13. The method of claim 8, wherein promoting the modified result set comprises visually displaying at least a portion of the modified result set.

14. The method of claim 8, wherein most recent entries are scanned first such that, when a match is identified, older entries are removed from the result set.

15. A non-transitory computer program product storing instructions, which when executed by one or more data processors, result in operations comprising:

performing, by at least one processor, a search of an insert-only database using a search string to obtain a result set having both valid and invalid entries, each entry in the insert-only database having an associated timestamp, the valid entries having a most recent timestamp and the invalid entries each having an earlier timestamp than a subsequent corresponding valid entry, wherein modification of at least one field in an entry in the insert-only database results in a corresponding entry being saved in a secondary data storage that comprises information characterizing the entry in the insert-only database including the timestamp for the entry;

scanning, by at least one processor, primary key fields of entries in the secondary data storage corresponding to the entries in the result set to determine which entries are valid based on their timestamps; and

removing, by at least one processor, invalid entries from the result set to result in a modified result set.

16. The non-transitory computer program product of claim 15, wherein the search uses a search string in a non-key field.

17. The non-transitory computer program product of claim 15, further comprising:

promoting, by at least one processor, the modified result set.

18. The non-transitory computer program product of claim 15, wherein promoting the modified result set comprises storing the modified result set and/or transmitting the modified result set to a remote server.

19. The non-transitory computer program product of claim 15, wherein promoting the modified result set comprises visually displaying at least a portion of the modified result set.

20. The non-transitory computer program product of claim 15, wherein most recent entries as defined by the timestamps are scanned first such that, when a match is identified, older entries are removed from the result set.