Abstract: A method, system, and/or computer program product queries a distributed database system. In one embodiment, the query method comprises: parsing a query request; generating an access plan for the query request, wherein the access plan specifies therein a database table related to the query request, and the database table has a plurality of copies stored in different database devices respectively; selecting, based on status information of each of the plurality of copies of the specified database table, one copy from the plurality of copies as a target database table; and executing a query operation in the target database table according to the access plan.

Abstract: A method, system, and/or computer program product queries a distributed database system. In one embodiment, the query method comprises: parsing a query request; generating an access plan for the query request, wherein the access plan specifies therein a database table related to the query request, and the database table has a plurality of copies stored in different database devices respectively; selecting, based on status information of each of the plurality of copies of the specified database table, one copy from the plurality of copies as a target database table; and executing a query operation in the target database table according to the access plan.

Abstract: A method, system, and/or computer program product queries a distributed database system. In one embodiment, the query method comprises: parsing a query request; generating an access plan for the query request, wherein the access plan specifies therein a database table related to the query request, and the database table has a plurality of copies stored in different database devices respectively; selecting, based on status information of each of the plurality of copies of the specified database table, one copy from the plurality of copies as a target database table; and executing a query operation in the target database table according to the access plan.

Abstract: A database query by using a user-defined function (UDF) is provided. A computer-implemented method for performing the database query by using the UDF includes detecting whether a command for invoking the UDF to transmit a parameter value has been received. Based on detecting that the command for invoking the UDF to transmit the parameter value has been received: a first interface of the UDF is started; the parameter value is received through the first interface; and the received parameter value is transmitted to an external data source. The method further includes returning to detecting whether the command for invoking the UDF to transmit the parameter value has been received.

Abstract: A computer implemented method for locating isolation points in an application under multi-tenant environment includes scanning, using a computer device an application by using scanning rules, to obtain potential isolation points and relationships between the potential isolation points; specifying at least one isolation point among the potential isolation points; and screening an isolation point from the potential isolation points by using relationships between the specified at least one isolation point and the remaining potential isolation points.

Abstract: A method, system, and/or computer program product queries a distributed database system. In one embodiment, the query method comprises: parsing a query request; generating an access plan for the query request, wherein the access plan specifies therein a database table related to the query request, and the database table has a plurality of copies stored in different database devices respectively; selecting, based on status information of each of the plurality of copies of the specified database table, one copy from the plurality of copies as a target database table; and executing a query operation in the target database table according to the access plan.

Abstract: An apparatus for locating isolation points in an application under multi-tenant environment includes a scanning module configured to scan the application, by using scanning rules, to obtain potential isolation points and relationships between the potential isolation points; a specifying module configured to specify at least one isolation point among the potential isolation points; and an isolation point screening module configured to screen an isolation point from the potential isolation points by using relationships between the specified at least one isolation point and the remaining potential isolation points.

Abstract: A computer implemented method for locating isolation points in an application under multi-tenant environment includes scanning, using a computer device an application by using scanning rules, to obtain potential isolation points and relationships between the potential isolation points; specifying at least one isolation point among the potential isolation points; and screening an isolation point from the potential isolation points by using relationships between the specified at least one isolation point and the remaining potential isolation points.