STATEMENT LOGGING IN DATABASES

• US 20100030824A1
• Filed: 07/31/2008
• Published: 02/04/2010
• Est. Priority Date: 07/31/2008
• Status: Active Grant

• Current Assignee: Sybase Incorporated (SAP SE)
• Original Assignee: Sybase Incorporated (SAP SE)
• Inventors: LORA-GALLARDO, Elena Isabel, SARAPUK, Andrzej, SHANG, Heping
• Granted Patent: US 8,676,749 B2
• Time in Patent Office: Days
• US Class Current: N/A
• CPC Class Codes: G06F 11/1471 involving logging of persistent data for recovery
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence
• CPC Class Codes: G06F 11/2097 maintaining the standby controller/processing unit updated initialisation or re-synchronisation thereof G06F11/1658 and subgroups

Abstract

System, method, computer program product embodiments and combinations and sub-combinations thereof for logging of data manipulation language (DML) statements are described herein. An embodiment includes a database engine, a replication agent and a replication server which replicates data from the database engine to one or more replicate databases. The database engine writes parsed query information into a transaction log so that a process of replication agent may read the parsed query information and forward it to the replication server. The database engine writes all log records associated with a statement in a manner that allows the replication server to distinguish if those log records belong to same statement. In another embodiment, replication agent selectively sends SQL statement information to the replication server based on the replication server architecture.

Claims

1. A method for logging data manipulation language (DML) statements, comprising:

receiving a plurality of parsed DML statements; and

logging one or more log records associated with said statements using at least a begin record marker and an end record marker to logically separate log records associated with each DML statement.

2. The method of claim 1, further comprising:

reading said log records;

reading said begin record marker; and

reading said end record marker.

3. The method of claim 1, further comprising:

transmitting said log records to a replication server.

4. The method of claim 3, further comprising:

identifying log records associated with a DML statement; and

selectively applying individual log records of modifications or individual statements at a replicate database.

5. The method of claim 1, wherein said logging step comprises:

logging said normalized statements as parameters of a virtual stored procedure.

6. A method of logging data manipulation language (DML) statements, comprising:

logging DML statement information only when the number of rows affected by a DML statement in a log record reached a configurable threshold.

7. The method of claim 6, wherein said logging step comprises:

placing a marker to identify the first log record logged for a statement.

8. A system for logging data manipulation language (DML) statements, comprising:

a database engine operable to log DML transactions in a transaction log using at least a begin record marker and an end record marker to logically separate statements inside a transaction;

a replication agent operable to read said data and statements from said transaction log; and

a replication server operable to receive said transactions from said replication agent.

9. The system of claim 9, wherein said database engine includes said transaction log.

10. The system of claim 9, further comprising:

one or more replicate databases.

11. The system of claim 9, wherein said transaction log further comprises a plurality of log records.

12. The system of claim 12, wherein each log record is associated with a transaction ID.

13. A computer program product having control logic stored therein, said control logic enabling a processor to replicate a data manipulation language statement, said control logic comprising:

receiving means for enabling a processor to receive a plurality of parsed DML statements; and

storing means for enabling a processor to store one or more log records associated with said statements using at least a begin record marker and an end marker to logically separate log records associated with each of said DML statements.

14. A computer program product having control logic stored therein, said control logic enabling a processor to replicate a data manipulation language statement, said control logic comprising:

sending means for enabling a processor to selectively send DML statement information when said estimate matches a configurable threshold associated with said DML statement.