Consistent query execution in hybrid dbms

A computer program product, 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 device to cause the device to perform a method comprising:

• generating, by one or more processors, a table that exists as a first instance in a first database and as a second instance in a second database;
• generating, by the one or more processors, a current replication batch of pooled changes of the first instance that committed at or before a first time;
• propagating, by the one or more processors, changes specified in the current replication batch to the second instance;
• assigning, by the one or more processors, a batch-ID of the current replication batch to the query;
• executing, by the one or more processors, the query on the second instance using the batch-ID as a filter to exclude any changes that have an assigned batch-ID of a replication batch having committed later than the current replication batch;
• and
• returning, by the one or more processors, results of the query execution on the second instance.

A computer system, the computer system comprising:

• one or more computer processors;
• at least one computer readable storage medium that is not a transitory signal per se;
• and
• program instructions stored on the at least one computer readable storage medium, the program instructions being executable by at least one computer processor of the one or more computer processors to cause the at least one computer processor to perform a method comprising:
• generating, by one or more processors, a table that exists as a first instance in a first database and as a second instance in a second database;
• generating, by the one or more processors, a current replication batch of pooled changes of the first instance that committed at or before a first time;
• propagating, by the one or more processors, changes specified in the current replication batch to the second instance;
• assigning, by the one or more processors, a batch-ID of the current replication batch to the query;
• executing, by the one or more processors, the query on the second instance using the batch-ID as a filter to exclude any changes that have an assigned batch-ID of a replication batch having committed later than the current replication batch;
• and
• returning, by the one or more processors, results of the query execution on the second instance.