Database management system and method of operation

A computer program product for operating a database management system (DBMS), wherein the database management system comprises a source database and a target database and is configured for asynchronously replicating data changes of the source database to the target database, the computer program product comprising a computer readable storage medium having program instructions embodied therewith, wherein the computer readable storage medium is not a transitory signal per se, the program instructions executable by a computer to cause the computer to perform a method, comprising:

• the DBMS receiving a request to perform a statement, the requested statement being a database read statement;
• the DBMS identifying a requested transaction to which the requested statement belongs;
• the identifying the most recently committed one of a plurality of transactions having been committed in the source database before receiving the request;
• the DBMS delaying execution of the requested statement in the target database until the identified most recently committed transaction has been replicated to the target database;
• after the delaying, the DBMS transferring all uncommitted data changes having been imposed by all statements, preceding the requested statement and being contained in the identified requested transaction from the source database to the target database;
• and applying the transferred changes also on the target database;
• the DBMS executing the requested statement on the target database, thereby reading data from the target database, the read data also comprising at least some of the transferred data changes;
• the DBMS returning the read data;
• after returning the read data, the DBMS undoing the applied data changes in the target database which have been imposed by the preceding statements.

A database management system comprising:

• a source database;
• a target database;
• a database management computer system for operating a database management system, the computer system comprising:
• one or more computer processors, one or more computer-readable storage media, and program instructions stored on one or more of the computer-readable storage media for execution by at least one of the one or more processors, the program instructions being configured for:
• asynchronously replicating data changes of the source database to the target database;
• receiving a request to perform a statement, the statement being a database statement;
• identifying the most recently committed one of a plurality of transactions having been committed in the source database before the receiving of the request;
• repeatedly identifying the one of the plurality of transactions having been replicated most recently to the target database;
• delaying execution of the requested statement in the target database until an evaluation of the repeatedly identified most recently replicated transaction returns that the identified most recently committed transaction has been replicated to the target database;
• after the delaying, executing the requested statement in the target database.