Abstract: Disclosed herein are system, method, and computer program product embodiments for generating a single transaction data stream from multiple database logs. An embodiment operates by assigning a first unique identifier to a first log entry associated with a disk store, a second unique identifier to a second log entry associated with in an in memory row store, and a third unique identifier to a third log entry based on the second unique identifier. The embodiment further operates by determining a first stream package based on the first log entry, a second stream package based on the third log entry, and a replay order for the first stream package and the second stream package based on the unique identifiers. In some embodiments, the operation further includes sending the first stream package and the second stream package to a replicant server in accordance with the replay order.

Abstract: Disclosed herein are system, method, and computer program product embodiments for generating a single transaction data stream from multiple database logs. An embodiment operates by assigning a first unique identifier to a first log entry associated with a disk store, a second unique identifier to a second log entry associated with in an in memory row store, and a third unique identifier to a third log entry based on the second unique identifier. The embodiment further operates by determining a first stream package based on the first log entry, a second stream package based on the third log entry, and a replay order for the first stream package and the second stream package based on the unique identifiers. In some embodiments, the operation further includes sending the first stream package and the second stream package to a replicant server in accordance with the replay order.

Abstract: Disclosed herein are system, method, and computer program product embodiments for generating a single transaction data stream from multiple database logs. An embodiment operates by assigning a first unique identifier to a first log entry associated with a disk store, a second unique identifier to a second log entry associated with in an in memory row store, and a third unique identifier to a third log entry based on the second unique identifier. The embodiment further operates by determining a first stream package based on the first log entry, a second stream package based on the third log entry, and a replay order for the first stream package and the second stream package based on the unique identifiers. In some embodiments, the operation further includes sending the first stream package and the second stream package to a replicant server in accordance with the replay order.

Abstract: Disclosed in some examples is a method of database replication, the method including at a Relational Database Management System (RDMS), determining a first replication mode; identifying a triggering event; determining that the triggering event indicates a change in the first replication mode; responsive to determining that the triggering event indicates a change in the first replication mode, determining a second replication mode, the second replication mode being a different replication mode than the first replication mode; identifying a database change made by one or more database tasks; and replicating the database change to an external replication component according to the second replication mode.

Abstract: Disclosed herein are system, method, and computer program product embodiments for generating a single transaction data stream from multiple database logs. An embodiment operates by assigning a first unique identifier to a first log entry associated with a disk store, a second unique identifier to a second log entry associated with in an in memory row store, and a third unique identifier to a third log entry based on the second unique identifier. The embodiment further operates by determining a first stream package based on the first log entry, a second stream package based on the third log entry, and a replay order for the first stream package and the second stream package based on the unique identifiers. In some embodiments, the operation further includes sending the first stream package and the second stream package to a replicant server in accordance with the replay order.

Abstract: Various embodiments of systems, computer program products, and methods to provide mode switching in high availability disaster recovery (HADR) systems are described herein. In an aspect, an average commit wait time associated with replicating data from a primary database to a replication database is determined based on a previous average commit wait time and a current commit wait time. A counter is incremented when the average commit wait time is greater than or equal to the predefined maximum commit wait time. Further, a check is made to determine whether the counter is greater than or equal to a predefined threshold and whether a predefined timer associated with the counter is expired. When the counter is greater than or equal to the predefined threshold and the predefined timer is running, the primary database is switched from a synchronous mode to an asynchronous mode for replicating the data.

Abstract: Various embodiments of systems, computer program products, and methods to provide mode switching in high availability disaster recovery (HADR) systems are described herein. In an aspect, an average commit wait time associated with replicating data from a primary database to a replication database is determined based on a previous average commit wait time and a current commit wait time. A counter is incremented when the average commit wait time is greater than or equal to the predefined maximum commit wait time. Further, a check is made to determine whether the counter is greater than or equal to a predefined threshold and whether a predefined timer associated with the counter is expired. When the counter is greater than or equal to the predefined threshold and the predefined timer is running, the primary database is switched from a synchronous mode to an asynchronous mode for replicating the data.

Abstract: Systems and methods are presented for completing transactions in a synchronous replication environment. In some embodiments, a computer-implemented method can include generating in a database server, an identifier to identify a database transaction. The method can also include transmitting the identifier to a replication server; receiving acknowledgement that the identifier is acknowledged by the replication server; storing the transaction in the database server; and executing the transaction after receiving acknowledgement from the replication server and after determining the transaction is stored in the database server; wherein transmitting the identifier to the replication server occurs in parallel with storing the transaction in the database server.

Abstract: Disclosed in some examples is a method of database replication, the method including at a Relational Database Management System (RDMS), determining a first replication mode; identifying a triggering event; determining that the triggering event indicates a change in the first replication mode; responsive to determining that the triggering event indicates a change in the first replication mode, determining a second replication mode, the second replication mode being a different replication mode than the first replication mode; identifying a database change made by one or more database tasks; and replicating the database change to an external replication component according to the second replication mode.

Abstract: Log based replication using parallel scanners is described. An example method includes establishing replication paths from a primary database to a plurality of destination servers. A plurality of scanner threads are spawned to scan a transaction log of the primary database. Specifically, one scanner thread is assigned to each replication path corresponding to each destination server. For each scanner thread, data bound to a replication path associated with the scanner thread is selected from a subset of the transaction log. Accordingly, the data is distributed to a destination server associated with the replication path.

Abstract: Disclosed in some examples is a method of database replication, the method including at a Relational Database Management System (RDMS), determining a first replication mode; identifying a triggering event; determining that the triggering event indicates a change in the first replication mode; responsive to determining that the triggering event indicates a change in the first replication mode, determining a second replication mode, the second replication mode being a different replication mode than the first replication mode; identifying a database change made by one or more database tasks; and replicating the database change to an external replication component according to the second replication mode.

Abstract: Disclosed herein are system, method, and computer program product embodiments for replicating data in a distributed database system. Data containing a replicated truncation point associated with a replicating system is received via a data path. It can then be determined that the truncation point represents the point at which all data in a transaction log has been replicated (e.g., successfully or safely) and the transaction log can then be truncated at the truncation point (i.e., the data up to the truncation point deflected). Data containing an additional replicated truncation point associated with an additional replicating system via an additional data path may be received. It can then be determined that the additional replicated truncation point represents the point at which all data in the transaction log has been replicated and the transaction log can be then truncated at the additional replicated truncation point.

Abstract: Disclosed in some examples is a method of database replication, the method including at a Relational Database Management System (RDMS), determining a first replication mode; identifying a triggering event; determining that the triggering event indicates a change in the first replication mode; responsive to determining that the triggering event indicates a change in the first replication mode, determining a second replication mode, the second replication mode being a different replication mode than the first replication mode; identifying a database change made by one or more database tasks; and replicating the database change to an external replication component according to the second replication mode.

Abstract: Systems and methods are presented for completing transactions in a synchronous replication environment. In some embodiments, a computer-implemented method can include generating in a database server, an identifier to identify a database transaction. The method can also include transmitting the identifier to a replication server; receiving acknowledgement that the identifier is acknowledged by the replication server; storing the transaction in the database server; and executing the transaction after receiving acknowledgement from the replication server and after determining the transaction is stored in the database server; wherein transmitting the identifier to the replication server occurs in parallel with storing the transaction in the database server.

Abstract: Log based replication using parallel scanners is described. An example method includes establishing replication paths from a primary database to a plurality of destination servers. A plurality of scanner threads are spawned to scan a transaction log of the primary database. Specifically, one scanner thread is assigned to each replication path corresponding to each destination server. For each scanner thread, data bound to a replication path associated with the scanner thread is selected from a subset of the transaction log. Accordingly, the data is distributed to a destination server associated with the replication path.

Abstract: Disclosed herein are system, method, and computer program product embodiments for replicating data in a distributed database system. Data containing a replicated truncation point associated with a replicating system is received via a data path. It can then be determined that the truncation point represents the point at which all data in a transaction log has been replicated (e.g., successfully or safely) and the transaction log can then be truncated at the truncation point (i.e., the data up to the truncation point deflected). Data containing an additional replicated truncation point associated with an additional replicating system via an additional data path may be received. It can then be determined that the additional replicated truncation point represents the point at which all data in the transaction log has been replicated and the transaction log can be then truncated at the additional replicated truncation point.