International Business Machines Corporation

Jens Mueller

Daniel Martin

Andreas Brodt

Knut Stolze

Namik Hrle

Bjoern Broll

Felix O Beier

Oliver Schiller

Nicole Finnie

A method, system and computer program product for copying data from a source database to a target database. A first database engine of the source database assigns a data-change-ID to each changed row in the source table. The data rows of the source table are stored in a plurality of source pages. Each source page comprises a source-page-ID and a highest-data-change-ID indicating its most recently changed data row. The target table comprises a source-page-ID-column. A second database engine of the target database maintains a metadata table comprising a source-page-ID column and a highest-data-change-ID column. The highest-data-change-IDs in the metadata table are compared with the highest-data-change-IDs of the source pages for selectively copying source table rows of source pages whose highest-data-change-ID is higher than their highest-data-change-ID in the metadata table to the target table.

Copying data changes to a target database

The present disclosure relates to a method for processing queries in a database system having a first database engine and a second database engine. The method includes: encrypting at least one predefined column of a first instance of a first table, resulting in a second instance of the first table containing at least part of the data of the first table in encrypted format. It may be determined whether to execute a received query in the first database engine on the first instance of the first table or in the second database engine on the second instance of the first table, where the determination involves a comparison of the query with encryption information.

Transparent analytical query accelerator over encrypted data

The present disclosure relates to a method for processing queries in a database system having a first database engine and a second database engine. The method includes: storing a first instance of a first table in the first database engine in plaintext; encrypting at least one predefined column of the first table, resulting in a second instance of the first table containing at least part of the data of the first table in encrypted format. The second instance of the first table in the second database engine is stored in the second database engine. It may be determined whether to execute a received query in the first database engine on the first table or in the second database engine on the second instance of the first table, where the determination involves a comparison of the query with encryption information.

Embodiments are provided for replicating a relational source database associated with a transaction log of the relational source database. In operation, embodiments may perform receiving a request for replicating data of the relational source database to a relational target database and identifying a first start position within the transaction log. Upon having identified the first start position, embodiments may further perform waiting at least a time period for ensuring that each transaction currently executing on the relational source database at a moment of receiving said request has terminated at an end of said time period. After having waited said time period, embodiments may perform an asynchronously creating of a copy of data of the relational source database to produce a created copy. In turn, embodiments may perform writing the created copy to the relational target database and identifying a repair start position within the transaction log.

Replication of a relational database

The disclosure relates to a system comprising a first and a second database engine and a replication module. The replication module replicates changes from a first database maintained by the first engine to a second database maintained by the second engine. The system maps state times and sync times. The state times are specified in a first temporal reference system used by the first engine and the sync times are specified in a second temporal reference system used by the second engine. Each mapped state time and sync time pair indicate an identical state of the first and second database or parts thereof. The system executes a query partially by the first and partially by the second engine and uses the mapping to execute the query by the first and/or second engine on data of a single defined state.

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Stuttgart, Germany

Jens Mueller