1. A computer-implemented database online reorganization method for dynamically adapting a database partitioning layout of a database containing tables, wherein the tables are vertically partitioned into containers, each container containing one or more attributes of one table, the method comprising: analyzing, by a workload analysis tool of a computer system, a workload on a set of tables of the database, the workload comprising queries; detecting, by the workload analysis tool of the computer system, a workload change of the workload; analyzing, by a workload evaluation tool of the computer system, if a new partitioning layout for the set of tables is considered optimal in view of the workload change; and deciding, by the workload evaluation tool of the computer system, whether the partitioning layout of the set of tables is switched to the new partitioning layout, wherein deciding whether the partitioning layout of the set of tables is switched to the new partitioning layout comprises: determining the workload costs of the current partitioning layout, the workload costs of the partitioning layout that is considered optimal in view of the workload change, and the penalty costs as the difference between the workload costs of the current partitioning layout and the workload costs of the partitioning layout that is considered optimal in view of the workload change; determining the transition costs for changing the current partitioning layout to the partitioning layout that is considered optimal in view of the workload change; determining weighted penalty costs by multiplying the penalty costs with a weight factor; determining new accumulated penalty costs by adding the weighted penalty costs to previously accumulated penalty costs; and triggering the switching of the partitioning layout of the set of tables from the current partitioning layout to the partitioning layout that is considered optimal in view of the workload change if the new accumulated penalty costs is larger than the transition costs.