Transaction Control Block for Multiversion Concurrency Commit Status

Patent metadata

Field	Value
Publication number	US-2016147906-A1
Application number	US-201414552808-A
Country	US
Kind code	A1
Filing date	Nov 25, 2014
Priority date	Nov 25, 2014
Publication date	May 26, 2016
Grant date	—

Abstract

Disclosed herein are system, method, and computer program product embodiments for utilizing a transaction control block for providing reader-writer access to transaction commit status. An embodiment operates by receiving a row read request and determining that the row is versioned. The system determines that a first timestamp information for a row destroy transaction associated with the row exists in a transaction control block and retrieves the first timestamp information from the transaction control block.

First claim

What is claimed is:

1 . A computer implemented method for reading versioned data in a database, comprising:
receiving, by at least one processor, a row read request; determining, by the at least one processor, that the row is versioned; determining, by the at least one processor, that first timestamp information for a row destroy transaction associated with the row exists in a transaction control block; and retrieving, by the at least one processor, the first timestamp information from the transaction control block.

2 . The method of claim 1 , further comprising:
determining that second timestamp information for a row create transaction associated with the row exists in the transaction control block.

3 . The method of claim 2 , further comprising:
determining whether to return the row based on the first or second timestamp, and on a consistent view timestamp associated with the read request.

4 . The method of claim 3 , wherein the determining whether to return the row further comprises determining to return the row when the consistent view timestamp and the first timestamp information indicate the row destroy transaction had not committed at a time of the consistent view timestamp.

5 . The method of claim 3 , wherein the determining whether to return the row further comprises determining to return the row when the consistent view timestamp and the second timestamp information indicate the row create operation had committed at a time of the consistent view timestamp.

6 . The method of claim 1 , wherein the transaction control block comprises a transaction state indicator and a transaction identifier, wherein the transaction identifier is associated with a plurality of transactions.

7 . The method of claim 6 , further comprising:
deriving commit information from the transaction control block; and storing the derived commit information into a version information structure associated with a plurality of rows associated with at least one of the plurality of transactions.

8 . A system, comprising:
a memory; and at least one processor coupled to the memory and configured to:
receive a row read request;
determine that the row is versioned;
determining that first timestamp information for a row destroy transaction associated with the row exists in a transaction control block; and
retrieving the first timestamp information, from the transaction control block.

9 . The system of claim 8 , the at least one processor further configured to:
determine that second timestamp information for a row create transaction associated with the row exists in the transaction control block.

10 . The system of claim 9 , the at least one processor further configured to:
determine whether to return the row based on the first or second timestamp, and on a consistent view timestamp associated with the read request.

11 . The system of claim 10 , wherein to the determine whether to return the row the at least one processor is configured to determine to return the row when the consistent view timestamp and the first timestamp information indicate the row destroy transaction had not committed at a time of the consistent view timestamp.

12 . The system of claim 10 , wherein to determine whether to return the row the at least one processor is configured to determine to return the row when the consistent view timestamp and the second timestamp information indicate the row create operation had committed at a time of the consistent view timestamp.

13 . The system of claim 8 , wherein the transaction control block comprises a transaction state indicator and a transaction identifier, wherein the transaction identifier is associated with a plurality of transactions.

14 . The system of claim 13 , the at least one processor further configured to:
derive commit information from the transaction control block; and store the derived commit information into a version information structure associated with a plurality of rows associated with at least one of the plurality of transactions.

15 . A tangible computer-readable device having instructions stored thereon that, when executed by at least one computing device, causes the at least one computing device to perform operations comprising:
receiving a row read request; determining that the row is versioned; determining that first timestamp information for a row destroy transaction associated with the row exists in a transaction control block; and retrieving the first timestamp information from the transaction control block.

16 . The computer-readable device of claim 15 , further comprising:
determining that second timestamp information for a row create transaction associated with the row exists in the transaction control block.

17 . The computer-readable device of claim 16 , further comprising:
determining whether to return the row based on the first or second timestamp, and on a consistent view timestamp associated with the read request.

18 . The computer-readable device of claim 17 , wherein the determining whether to return the row further comprises determining to return the row when the consistent view timestamp and the first timestamp information indicate the row destroy transaction had not committed at a time of the consistent view timestamp.

19 . The computer-readable device of claim 17 , wherein the determining whether to return the row further comprises determining to return the row when the consistent view timestamp and the second timestamp information indicate the row create operation had committed at a time of the consistent view timestamp.

20 . The computer-readable device of claim 15 , wherein the transaction control block comprises a transaction state indicator and a transaction identifier, wherein the transaction identifier is associated with a plurality of transactions.

Assignees

• Schreter Ivan
• Park Chang-Gyoo

Inventors

• Schreter Ivan
• Park Chang-Gyoo

Classifications

• G06F16/9038 Primary

  Presentation of query results · CPC title

• G06F16/219

  Managing data history or versioning (querying versioned data G06F16/2474; querying temporal data G06F16/2477) · CPC title

• G06F16/1873

  Versioning file systems, temporal file systems, e.g. file system supporting different historic versions of files · CPC title

• G06F16/2322 Primary

  using timestamps · CPC title

• G06F16/2329

  using versioning · CPC title