Patent Publication Number: US-11379211-B2

Title: Fencing execution of external tools during software changes

Description:
BACKGROUND 
     During standard execution, applications are configured to read and write data from tables. Software upgrades may include software and data changes. During software upgrade processes, an original application may be set to read and write only data from original tables that have not been changed. Generally, data changed during the software upgrade processes is not accessible for reading or writing by the original application. The upgraded data usually becomes accessible after the software upgrade process is completed. A typical approach for handling software changes is initiated by an upgrade tool that creates a clone of the tables used by the application being changed. The typical approach can ensure that the software change process does not disturb actual tables written to by the application. During the upgrade, transport data is deployed to a clone-table. After the upgrade, a production environment is switched to use the clone-table. There are drawbacks associated with the typical approach. 
     SUMMARY 
     The present disclosure describes techniques for upgrading applications. 
     In a particular implementation, a computer-implemented method includes: receiving an upgrading request for an original table of an application, generating an upgraded table including a structure matching the original table, setting a session variable to initiate an application upgrade, and adding a set of triggers to the original table to selectively control read operations and write operations for the original table and the upgraded table based on the session variable. 
     Implementations of the described subject matter, including the previously described implementation, can be implemented using a computer-implemented method; a non-transitory, computer-readable medium storing computer-readable instructions to perform the computer-implemented method; and a computer-implemented system comprising one or more computer memory devices interoperably coupled with one or more computers and having tangible, non-transitory, machine-readable media storing instructions that, when executed by the one or more computers, perform the computer-implemented method/the computer-readable instructions stored on the non-transitory, computer-readable medium. 
     The subject matter described in this specification can be implemented so as to realize one or more of the following advantages. Implementations of the present disclosure can include a modification of a multisystem landscape to provide temporarily fencing of execution of an external tool during software changes to support upgrading of applications and corresponding tables, thereby reducing downtime, as well as reducing storage and processing requirements. For example, downtime can be reduced by generating “hidden changes” of tables in a database (that are not visible to a client of the production system) and substantially instantaneously switching from an original table and an original application to an upgraded table and an upgraded application. Under the described approach, the multi-system landscape includes reading and writing database triggers that selectively manage writing and reading operations in the original and the upgraded tables, without the need to completely replicate large data sets. For example, not all data entries need to be copied for upgraded applications. Using the described implementation enables time and resource management, such that only relevant data (data associated with upgraded applications) is extracted from the original tables and upgraded. Additionally, the upgraded data can be stored using formats that minimize storage requirements. Further, the disclosed system enables parallel upgrading procedures to upgrade multiple components (modules) of an application and seamlessly switch from the original components of the application to the upgraded components of the application. 
     The details of one or more implementations of the subject matter of this specification are set forth in the Detailed Description, the Claims, and the accompanying drawings. Other features, aspects, and advantages of the subject matter will become apparent to those of ordinary skill in the art from the Detailed Description, the Claims, and the accompanying drawings. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a block diagram illustrating component/data relationships for an upgrading applications framework, according to an implementation of the present disclosure. 
         FIGS. 2A-2C  are flowcharts illustrating examples of computer-implemented methods for upgrading applications, according to some implementations of the present disclosure. 
         FIG. 3  is a block diagram illustrating an example of a computer-implemented system used to provide computational functionalities associated with described algorithms, methods, functions, processes, flows, and procedures, according to an implementation of the present disclosure. 
     
    
    
     Like reference numbers and designations in the various drawings indicate like elements. 
     DETAILED DESCRIPTION 
     The following detailed description describes techniques for performing upgrading applications in a multi-system landscape and is presented to enable any person skilled in the art to make and use the disclosed subject matter in the context of one or more particular implementations. Various modifications, alterations, and permutations of the disclosed implementations can be made and will be readily apparent to those of ordinary skill in the art, and the general principles defined can be applied to other implementations and applications, without departing from the scope of the present disclosure. In some instances, one or more technical details that are unnecessary to obtain an understanding of the described subject matter and that are within the skill of one of ordinary skill in the art may be omitted so as to not obscure one or more described implementations. The present disclosure is not intended to be limited to the described or illustrated implementations, but to be accorded the widest scope consistent with the described principles and features. 
     Multi-system landscapes are computing architectures including multiple different computing systems (for example, a quality system, a deployment system, and a production system), technologies and components that are operated by multiple personnel (for example, developers, administrators, and operators). The quality system is used to prepare application data and application changes. The quality system can ensure “quality” of upgraded applications through the use of testing. Upgraded (updated) applications and corresponding data can be packaged and transmitted to the production system by a deployment system. In optimal conditions, the upgraded applications are deployed to the production system with zero downtime. The production system is often considered as having higher priority for availability than the quality system because availability of the production system can affect multiple clients (users). For zero downtime deployment, upgraded data transported by the deployment system is invisible to the running production system. If the upgraded data is visible to the running production system, the deployed upgraded data can disrupt operation of the running production system. To prevent deployment errors, the upgraded data transported by the deployment system is generally locked against modifications by an original (not upgraded) application. 
     Several problems exist when using upgrading applications procedures in a current multi-system landscape. First, for example, an upgrade tool creates a clone of the tables used by the application and being changed that requires additional storage for the cloned tables. Applications are composites not only of code but also of configurations, database content, and calls to external services. For example, a database can store tens of thousands of tables, each with thousands or millions of data entries. Considering the large number of tables and their large sizes, cloning tables based on complete data replication implies major additional storage requirements (for example, approximately a third of the database can be specifically allocated to temporary cloned tables). Further, the current upgrade procedures require additional processing resources to clone the table and to run the triggers to replicate data. Additionally, modifications of a multi-system landscape for upgrading applications are related to decreased production speed. Current procedures for upgrading applications can slow down production, as database triggers (or “triggers”) are integrated, which act upon write operations. Another drawback is that the switch from a quality system to a production system requires a downtime, during which the application cannot be used. Techniques for upgrading applications can temporarily fence the application to efficiently manage data access and table changes. 
     Described is a content change management process using a multi-system landscape that can minimize storage and processing resources and can optimize table changes by upgrading applications without production downtime. Here, “better” is used in the sense of, among other things as will be appreciated by those of ordinary skill in the art, improved performance, less resource usage, easier to extend, and less impact on a software change to production. The described solution uses triggers to manage reading and writing of data and uses session variables to verify consistency of the upgrade process. The described solution provides upgraded tables without a duplication of large data sets. The upgrading approach includes “hidden changes” of tables in a database and substantially instantaneously switching on from an original to an upgraded table, without the need to replicate large data sets. In this way, tables in multi-system landscape can be upgraded with triggers that improve processes and applications. 
       FIG. 1  is a block diagram illustrating component/data relationships for a multi-system landscape  100  that employs a change management process, according to an implementation of the present disclosure.  FIG. 1  is provided for example purposes only to enhance understanding of the presented concepts. As will be appreciated for those of ordinary skill in the art, there are a myriad of possible ways to present or to arrange the presented components, to structure their interactions, or to describe inter/intra-component interactions/communications. In as far as they are consistent with this disclosure, the other possible presentations or arrangements, structures, or descriptions are considered to be within the scope of this disclosure. 
     At a high-level and in some implementations, the described multi-system landscape  100  includes a quality (development) system  102 , a deployment system  104 , and a production (operation) system  106 . The quality system  102  can be configured to perform the steps to recalculate new table values for an upgrade process. The quality system  102  includes a quality application  108  and a quality database  110 . The quality application  108  includes a content writer  112  and a user session  114 . The content writer  112  can be configured to write data in the quality original tables  116 . The user session  114  can be configured to define sessions, including upgrade sessions. For example, the user session  114  can be configured to mark a beginning of a session, an end of a session, and a session identifier. The quality database  110  includes quality original tables  116 , upgraded tables  118 , writing triggers  120 , and user session variables  122 . To initiate the upgrade of the quality application  108 , quality original tables  116  that are accessed by the quality application  108  are identified and their structure is determined. The upgrading tool is configured to generate empty upgraded tables  118  in the quality database  110  with structures matching the structure of the identified quality original tables  116 . A set of writing triggers  120  (such as, create trigger on insert, create trigger on update, create trigger on upsert) are created and added to the quality original table  116 . The writing triggers  120  can be configured to detect whether the content writer  112  writes data to the quality original tables. In response to detecting that new data is written, the writing triggers  120  can be configured to copy the data from the quality original tables  116  to the upgraded tables  118 . In some implementations, the data generated during the upgrade process can be filtered based on data types, such that only data associated to the upgraded application is stored to optimize data storage based on relevance. A user session variable  122  can be set in the quality database  110  by the user session module  114  of the quality application  108  to identify data written to the upgraded tables  118  during the upgrade procedure by the writing triggers  120 . The user session  114  can be configured to provide an output indicating that changes of the upgraded tables  118  are complete and the deployment system  104  can transport the upgraded tables  118  to the production system  106 . 
     The deployment system  104  can include an export tool  124 , an import tool  126 , and a table content file  128 . The export tool  124  can be configured to communicate with the upgraded tables  118 . The export tool  124  can read the data from the upgraded tables  118  and write the data to the table content file  128 . In some implementations, the data export tool  124  can be configured to provide an output to the database to indicate successful copy of the content of the upgraded tables  118 . In response to the indication of successful copy of the content of the upgraded tables  118 , the upgraded tables  118  are deleted from the quality database  110  and a subsequent scheduled (upgrading) session can start. In response to deployment of the content of the upgraded tables  118 , the import-tool  126  can read the data from the table content file  128  and write the content to the production system  106 . 
     The production system  106  includes a production application  130  and a production database  132 . The production system  106  (for example, application systems or tenants executing software) is used to read data associated with applications  130  for processing and upgrading procedures affecting the database  132 . In some implementations, the data is selected by an application code  134  of the production application  130  that is configured to communicate with the production database  132  (for example, an in-memory database such as SAP HANA), and an application server (for example, SAP ABAP). The production database  132  and the production application  130  can provide monitoring application programming interfaces (APIs) to read/collect statistical data during upgrades. The production database  132  includes production original tables  136 , upgraded tables  138 , reading triggers  140 , and an upgrade tool  142 . The production database  132  can be configured to generate empty upgraded tables  138  that match the structure of the production original tables  136  called by the production application  130  undergoing an upgrade process. The production database  132  receives as input the content of the upgraded tables  138  from import tool  126  of the deployment system  104 . In response to determining that the deployment is complete, the reading triggers  140  are configured to read data from the upgraded tables  138  or from the production original tables  136  based on a priority setting. The priority setting of the reading triggers  140  can ensure that the data is read consistently from the upgraded tables  138  rather than the production original tables  136  for upgraded applications. For example, during the upgrade process, the application code  134  transmits a read-access request to the production original tables  136 . The read request is re-directed to the reading trigger  140 . The reading trigger  140  determines whether the read request is generated by an original application or an upgraded application. In response to determining that the read request is received from an original application, the reading trigger  140  returns the respective value from the production original table  136 . In response to determining that the read request is received from an upgraded application, the reading trigger  140  returns the respective value from the upgraded table  138 , if a corresponding data entry is stored in the upgraded tables  138 . The upgrade tool  142  can read data from the upgraded tables  138 , execute the upgrade process, and “upsert” data (update data entry if a record exists or insert a data entry if a record does not exist) of the production original tables  136 . The upgrade tool  142  can be configured to determine the completion of the upgrade of the production original tables  136  and delete data from the upgraded tables  138 . In response to deleting the data from the upgraded tables  138 , the reading triggers  140  can be configured to replace reading from the upgraded tables  138  with reading from the production original tables  136 , which have been updated to include the upgraded data. 
       FIGS. 2A-2C  are flowcharts illustrating examples of computer-implemented methods  200 A,  200 B,  200 C for upgrading applications, according to some implementations of the present disclosure. For clarity of presentation, the description that follows generally describes methods  200 A,  200 B,  200 C in the context of the other figures in this description. However, it will be understood that methods  200 A,  200 B,  200 C can be performed, for example, by any system, environment, software, and hardware, or a combination of systems, environments, software, and hardware, as appropriate. The methods  200 A,  200 B,  200 C can be executed in series or independent from each other. In some implementations, various steps of methods  200 A,  200 B,  200 C can be run in parallel, in combination, in loops, or in any order. 
     In method  200 A, at  202 , an application-upgrade request is received. The application-upgrade request can include a request to upgrade an entire application, a version of an application, or a portion of the application (for example, one or more identified software modules). The application-upgrade request can include an identifier of the application to be upgraded. In some implementations, the application-upgrade request can be generated by a software developer in a quality system or by a customer interacting with the production system and transmitted to the quality system. The application-upgrade request can include a description of a software extension or upgrade. In some implementations, the application-upgrade request includes identifiers of a quality original table that is potentially affected by the upgrading procedure. After  202 , method  200 A proceeds from  202  to  204 . 
     At  204 , a structure of a quality original table that is potentially affected by the upgrading procedure is determined. The structure includes the size of the table (for example, number of rows and columns) and the data types stored within the table. After  204 , method  200 A proceeds to  206 . 
     At  206 , an empty upgraded table matching the structure of the quality original table is generated. For example, if the application-upgrade request is absent of an indication that an upgraded data type should be different from the original data type stored by the quality original table, the upgraded table is configured to have the same size as the quality original table and can be configured to store the same data type as the quality original table. Otherwise, if the application-upgrade request includes an indication that an upgraded data type should be different from the original data type, the upgraded table is configured to have the same size as the quality original table and can be configured to store one or more upgraded data types. After  206 , method  200 A proceeds to  208 . 
     At  208 , a session variable is set for the upgrade session. The session variable can include an identifier of an upgrade session, a (temporal) marker of a starting point of the upgrade session, and a (temporal) marker of a completion of the upgrade session. The session variable can be set in the quality database by a user session module of the quality application to identify data written to the upgraded tables during the upgrade procedure by writing triggers. A value of the session variable can be modified during the upgrade session, different values being configured to identify and trigger different operations. For example, the application logic can set the initial value of the session variable to zero or an empty field and during the update procedure the initial value of the session variable can be set to “upgrade” or “update”. The initial value of the session variable can be configured to trigger a switch to (initiation of) the new behavior (execution and testing of an upgrade process) in the quality system. Another value of the session variable can be configured to trigger generation of an output indicating that the changes of the upgraded tables are complete and the deployment system can transport the upgraded tables to the production system. After  2108 , method  200 A proceeds to  210 . 
     At  210 , writing triggers are added to the quality original table to copy data to the upgraded table. The writing triggers can include multiple trigger types, such as create trigger on insert, create trigger on update, or create trigger on upsert. The writing triggers can be configured to determine whether a content writer writes data to the quality original tables and, in response to determining that the content writer wrote data to the quality original tables, copy the recently written data from the quality original tables to the upgraded tables. In some implementations, the data copied to the upgraded tables includes the data recently written data in the quality original table and the session variable, identifying the upgrade session during which the data was copied. After  210 , method  200 A can proceed to method  200 B. 
     In method  200 B, at  212 , upgraded data previously written by an upgrade process is retrieved. After  212 , method  200 B proceeds to  214 . 
     At  214 , the upgraded data is filtered using the session variable. Data filtering includes determining whether each of the data entries in the upgraded table corresponds to a particular session variable, such as an empty field. The data filtering process distinguishes between the data written by the upgrade procedure and data written by a normal usage of the system. 
     In response to determining that a particular data entry in the upgraded table corresponds to the respective session variable (e.g., empty), method  200 B proceeds from  214  to  216 . At  216 , the writing triggers can be executed to continue the upgrading process. After  216 , method  200 B proceeds to  218 . 
     In response to determining that the remaining data in the upgraded tables includes another valid session variable (e.g., “upgrade”), the method  200 B proceeds from  214  to  218 . At  218 , the writing trigger can replicate the data written by the upgrade procedure to the upgraded table to continue the upgrading process. After  218 , method  200 B can loop back to  212  until all data written by the upgrade process is added to the upgraded table. In some implementations, the method  200 B loops back multiple (e.g., thousands of times) to update the upgraded tables repeatedly. After  218 , in response to determining that all triggered updates have been completed method  200 B can proceed to method  200 C. 
     In method  200 C, at  220 , in response to determining that the changes of the upgraded tables are complete, the content of the filtered upgraded tables is transported from the quality system to the production system. In some implementations, the deployment of upgraded data includes deletion of the upgraded data from the database of the quality system after the entire content of the upgraded data was copied. After  220 , method  200 C proceeds to  222 . 
     At  222 , reading triggers are added to the production system to manage data reading during a production phase of the upgrading procedure. In some implementations, in response to determining that the deployment of the upgraded data content is complete, the reading triggers are automatically generated and added to the production system. The reading triggers are configured to selectively read data from the upgraded tables or from the production original tables based on a priority setting. The priority setting of the reading triggers can ensure that the data is read consistently from the upgraded tables rather than the production original tables for upgraded applications. For example, during the upgrade process, the application code transmits a read-access request to the production original tables. The read request is re-directed to the reading triggers. The reading triggers determine whether the read request is generated by an original application or an upgraded application. In response to determining that the read request is received from an original application, the reading triggers return the respective value from the production original table. In response to determining that the read request is received from an upgraded application and that a corresponding data entry is stored in the upgraded tables, the reading triggers return the respective value from the upgraded table. After  222 , method  200 C proceeds to  224 . 
     At  224 , data read from the upgraded tables is added (upserted) to the production original tables. After  224 , method  200 C proceeds to  226 . 
     At  226 , an outcome (for example, success or failure) of the upgrade process is determined. For example, in response to determining that the upgrade of the production original tables is successfully completed, the data from the upgraded tables and the original application can be deleted. In some implementations, in response to deleting the data from the upgraded tables, the reading triggers can be configured to replace reading from the upgraded tables with reading from the production original tables. After  226 , method  200 C can stop or can loop back to  220 , or any of the methods  200 A and  200 B. 
     In some implementations, the methods  200 A,  200 B,  200 C can be performed in parallel for multiple upgrade sessions that do not interfere with each other (for example, correspond to separate application modules that call separate data entries in the original tables). Each of the parallel upgrade sessions can be separately identified by a respective session variable. For example, upgraded data corresponding to multiple upgrade sessions can be stored within a single upgraded table, each data entry being associated with a session variable that enables identification of the respective upgrade session. 
       FIG. 3  is a block diagram illustrating an example of a computer-implemented System  300  used to provide computational functionalities associated with described algorithms, methods, functions, processes, flows, and procedures, according to an implementation of the present disclosure. In the illustrated implementation, System  300  includes a Computer  302  and a Network  330 . 
     The illustrated Computer  302  is intended to encompass any computing device such as a server, desktop computer, laptop/notebook computer, wireless data port, smart phone, personal data assistant (PDA), tablet computer, one or more processors within these devices, another computing device, or a combination of computing devices, including physical or virtual instances of the computing device, or a combination of physical or virtual instances of the computing device. Additionally, the Computer  302  can include an input device, such as a keypad, keyboard, touch screen, another input device, or a combination of input devices that can accept user information, and an output device that conveys information associated with the operation of the Computer  302 , including digital data, visual, audio, another type of information, or a combination of types of information, on a graphical-type user interface (UI) (or GUI) or other UI. 
     The Computer  302  can serve in a role in a distributed computing system as a client, network component, a server, a database or another persistency, another role, or a combination of roles for performing image reconstruction as described in the present disclosure. The illustrated Computer  302  is communicably coupled with a Network  330 . In some implementations, one or more components of the Computer  302  can be configured to operate within an environment, including cloud computing based, local, global, another environment, or a combination of environments. 
     At a high level, the Computer  302  is an electronic computing device operable to receive, transmit, process, store, or manage data and information associated with the described subject matter. According to some implementations, the Computer  302  can also include or be communicably coupled with a server, including an application server, email server, web server, caching server, streaming data server, another server, or a combination of servers. 
     The Computer  302  can receive requests over Network  330  (for example, from a client software application executing on another Computer  302 ) and respond to the received requests by processing the received requests using a software application or a combination of software applications. In addition, requests can also be sent to the Computer  302  from internal users (for example, from a command console or by another internal access method), external or third parties, or other entities, individuals, systems, or computers. 
     Each of the components of the Computer  302  can communicate using a System Bus  303 . In some implementations, any or all of the components of the Computer  302 , including hardware, software, or a combination of hardware and software, can interface over the System Bus  303  using an application-programming interface (API)  312 , a Service Layer  313 , or a combination of the API  312  and Service Layer  313 . The API  312  can include specifications for routines, data structures, and object classes. The API  312  can be either computer-language independent or dependent and refer to a complete interface, a single function, or even a set of APIs. The Service Layer  313  provides software services to the Computer  302  or other components (whether illustrated or not) that are communicably coupled to the Computer  302 . The functionality of the Computer  302  can be accessible for all service consumers using the Service Layer  313 . Software services, such as those provided by the Service Layer  313 , provide reusable, defined functionalities through a defined interface. For example, the interface can be software written in JAVA, C++, another computing language, or a combination of computing languages providing data in extensible markup language (XML) format, another format, or a combination of formats. While illustrated as an integrated component of the Computer  302 , some implementations can illustrate the API  312  or the Service Layer  313  as stand-alone components in relation to other components of the Computer  302  or other components (whether illustrated or not) that are communicably coupled to the Computer  302 . Moreover, any or all parts of the API  312  or the Service Layer  313  can be implemented as a child or a sub-module of another software module, enterprise application, or hardware module without departing from the scope of the present disclosure. 
     The Computer  302  includes an Interface  304 . Although illustrated as a single Interface  304 , two or more Interfaces  304  can be used according to particular needs, desires, or particular implementations of the Computer  302 . The Interface  304  is used by the Computer  302  for communicating with another computing system (whether illustrated or not) that is communicatively linked to the Network  330  in a distributed environment. Generally, the Interface  304  is operable to communicate with the Network  330  and includes logic encoded in software, hardware, or a combination of software and hardware. More specifically, the Interface  304  can include software supporting one or more communication protocols associated with communications such that the Network  330  or hardware of Interface  304  is operable to communicate physical signals within and outside of the illustrated Computer  302 . 
     The Computer  302  includes a Processor  305 . Although illustrated as a single Processor  305 , two or more Processors  305  can be used according to particular needs, desires, or particular implementations of the Computer  302 . Generally, the Processor  305  executes instructions and manipulates data to perform the operations of the Computer  302  and any algorithms, methods, functions, processes, flows, and procedures as described in the present disclosure. 
     The Computer  302  also includes a Database  306  that can hold data for the Computer  302 , another component communicatively linked to the Network  330  (whether illustrated or not), or a combination of the Computer  302  and another component. For example, Database  306  can be an in-memory, disk storage, or another type of database storing data consistent with the present disclosure. In some implementations, Database  306  can be a combination of two or more different database types (for example, a hybrid in-memory and disk storage database) according to particular needs, desires, or particular implementations of the Computer  302  and the described functionality. Although illustrated as a single Database  306 , two or more databases of similar or differing types can be used according to particular needs, desires, or particular implementations of the Computer  302  and the described functionality. While Database  306  is illustrated as an integral component of the Computer  302 , in some implementations, Database  306  can be external to the Computer  302 . 
     The Computer  302  also includes a Memory  307  that can hold data for the Computer  302 , another component or components communicatively linked to the Network  330  (whether illustrated or not), or a combination of the Computer  302  and another component. Memory  307  can store any data consistent with the present disclosure. In some implementations, Memory  307  can be a combination of two or more different types of memory (for example, a combination of semiconductor and magnetic storage) according to particular needs, desires, or particular implementations of the Computer  302  and the described functionality. Although illustrated as a single Memory  307 , two or more Memories  307  of similar or differing types can be used according to particular needs, desires, or particular implementations of the Computer  302  and the described functionality. While Memory  307  is illustrated as an integral component of the Computer  302 , in some implementations, Memory  307  can be external to the Computer  302 . 
     The Application  308  is an algorithmic software engine providing functionality according to particular needs, desires, or particular implementations of the Computer  302 , particularly with respect to functionality described in the present disclosure. For example, Application  308  can serve as one or more components, modules, or applications. Further, although illustrated as a single Application  308 , the Application  308  can be implemented as multiple Applications  308  on the Computer  302 . In addition, although illustrated as integral to the Computer  302 , in some implementations, the Application  308  can be external to the Computer  302 . 
     The Computer  302  can also include a Power Supply  314 . The Power Supply  314  can include a rechargeable or non-rechargeable battery that can be configured to be either user- or non-user-replaceable. In some implementations, the Power Supply  314  can include power-conversion or management circuits (including recharging, standby, or another power management functionality). In some implementations, the Power Supply  314  can include a power plug to allow the Computer  302  to be plugged into a wall socket or another power source to, for example, power the Computer  302  or recharge a rechargeable battery. 
     There can be any number of Computers  302  associated with, or external to, a computer system containing Computer  302 , each Computer  302  communicating over Network  330 . Further, the term “client,” “user,” or other appropriate terminology can be used interchangeably, as appropriate, without departing from the scope of the present disclosure. Moreover, the present disclosure contemplates that many users can use one Computer  302 , or that one user can use multiple Computers  302 . 
     Described implementations of the subject matter can include one or more features, alone or in combination. 
     Implementations of the subject matter and the functional operations described in this specification can be implemented in digital electronic circuitry, in tangibly embodied computer software or firmware, in computer hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them. Software implementations of the described subject matter can be implemented as one or more computer programs, that is, one or more modules of computer program instructions encoded on a tangible, non-transitory, computer-readable medium for execution by, or to control the operation of, a computer or computer-implemented system. Alternatively, or additionally, the program instructions can be encoded in/on an artificially generated propagated signal, for example, a machine-generated electrical, optical, or electromagnetic signal that is generated to encode information for transmission to a receiver apparatus for execution by a computer or computer-implemented system. The computer-storage medium can be a machine-readable storage device, a machine-readable storage substrate, a random or serial access memory device, or a combination of computer-storage mediums. Configuring one or more computers means that the one or more computers have installed hardware, firmware, or software (or combinations of hardware, firmware, and software) so that when the software is executed by the one or more computers, particular computing operations are performed. 
     The term “real-time,” “real time,” “realtime,” “real (fast) time (RFT),” “near(ly) real-time (NRT),” “quasi real-time,” or similar terms (as understood by one of ordinary skill in the art), means that an action and a response are temporally proximate such that an individual perceives the action and the response occurring substantially simultaneously. For example, the time difference for a response to display (or for an initiation of a display) of data following the individual&#39;s action to access the data can be less than 1 millisecond (ms), less than 1 second (s), or less than 5 s. While the requested data need not be displayed (or initiated for display) instantaneously, it is displayed (or initiated for display) without any intentional delay, taking into account processing limitations of a described computing system and time required to, for example, gather, accurately measure, analyze, process, store, or transmit the data. 
     The terms “data processing apparatus,” “computer,” or “electronic computer device” (or an equivalent term as understood by one of ordinary skill in the art) refer to data processing hardware. Data processing hardware encompass all kinds of apparatuses, devices, and machines for processing data, including by way of example, a programmable processor, a computer, or multiple processors or computers. The computer can also be, or further include special purpose logic circuitry, for example, a central processing unit (CPU), a field programmable gate array (FPGA), or an application-specific integrated circuit (ASIC). In some implementations, the computer or computer-implemented system or special purpose logic circuitry (or a combination of the computer or computer-implemented system and special purpose logic circuitry) can be hardware- or software-based (or a combination of both hardware- and software-based). The computer can optionally include code that creates an execution environment for computer programs, for example, code that constitutes processor firmware, a protocol stack, a database management system, an operating system, or a combination of execution environments. The present disclosure contemplates the use of a computer or computer-implemented system with an operating system of some type, for example LINUX, UNIX, WINDOWS, MAC OS, ANDROID, IOS, another operating system, or a combination of operating systems. 
     A computer program, which can also be referred to or described as a program, software, a software application, a unit, a module, a software module, a script, code, or other component can be written in any form of programming language, including compiled or interpreted languages, or declarative or procedural languages, and it can be deployed in any form, including, for example, as a stand-alone program, module, component, or subroutine, for use in a computing environment. A computer program can, but need not, correspond to a file in a file system. A program can be stored in a portion of a file that holds other programs or data, for example, one or more scripts stored in a markup language document, in a single file dedicated to the program in question, or in multiple coordinated files, for example, files that store one or more modules, sub-programs, or portions of code. A computer program can be deployed to be executed on one computer or on multiple computers that are located at one site or distributed across multiple sites and interconnected by a communication network. 
     While portions of the programs illustrated in the various figures can be illustrated as individual components, such as units or modules, that implement described features and functionality using various objects, methods, or other processes, the programs can instead include a number of sub-units, sub-modules, third-party services, components, libraries, and other components, as appropriate. Conversely, the features and functionality of various components can be combined into single components, as appropriate. Thresholds used to make computational determinations can be statically, dynamically, or both statically and dynamically determined. 
     Described methods, processes, or logic flows represent one or more examples of functionality consistent with the present disclosure and are not intended to limit the disclosure to the described or illustrated implementations, but to be accorded the widest scope consistent with described principles and features. The described methods, processes, or logic flows can be performed by one or more programmable computers executing one or more computer programs to perform functions by operating on input data and generating output data. The methods, processes, or logic flows can also be performed by, and computers can also be implemented as, special purpose logic circuitry, for example, a CPU, an FPGA, or an ASIC. 
     Computers for the execution of a computer program can be based on general or special purpose microprocessors, both, or another type of CPU. Generally, a CPU will receive instructions and data from and write to a memory. The essential elements of a computer are a CPU, for performing or executing instructions, and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to, receive data from or transfer data to, or both, one or more mass storage devices for storing data, for example, magnetic, magneto-optical disks, or optical disks. However, a computer need not have such devices. Moreover, a computer can be embedded in another device, for example, a mobile telephone, a personal digital assistant (PDA), a mobile audio or video player, a game console, a global positioning system (GPS) receiver, or a portable memory storage device. 
     Non-transitory computer-readable media for storing computer program instructions and data can include all forms of permanent/non-permanent or volatile/non-volatile memory, media and memory devices, including by way of example semiconductor memory devices, for example, random access memory (RAM), read-only memory (ROM), phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), and flash memory devices; magnetic devices, for example, tape, cartridges, cassettes, internal/removable disks; magneto-optical disks; and optical memory devices, for example, digital versatile/video disc (DVD), compact disc (CD)-ROM, DVD+/−R, DVD-RAM, DVD-ROM, high-definition/density (HD)-DVD, and BLU-RAY/BLU-RAY DISC (BD), and other optical memory technologies. The memory can store various objects or data, including caches, classes, frameworks, applications, modules, backup data, jobs, web pages, web page templates, data structures, database tables, repositories storing dynamic information, or other appropriate information including any parameters, variables, algorithms, instructions, rules, constraints, or references. Additionally, the memory can include other appropriate data, such as logs, policies, security or access data, or reporting files. The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry. 
     To provide for interaction with a user, implementations of the subject matter described in this specification can be implemented on a computer having a display device, for example, a cathode ray tube (CRT), liquid crystal display (LCD), light emitting diode (LED), or plasma monitor, for displaying information to the user and a keyboard and a pointing device, for example, a mouse, trackball, or trackpad by which the user can provide input to the computer. Input can also be provided to the computer using a touchscreen, such as a tablet computer surface with pressure sensitivity, a multi-touch screen using capacitive or electric sensing, or another type of touchscreen. Other types of devices can be used to interact with the user. For example, feedback provided to the user can be any form of sensory feedback (such as, visual, auditory, tactile, or a combination of feedback types). Input from the user can be received in any form, including acoustic, speech, or tactile input. In addition, a computer can interact with the user by sending documents to and receiving documents from a client-computing device that is used by the user (for example, by sending web pages to a web browser on a user&#39;s mobile computing device in response to requests received from the web browser). 
     The term “graphical user interface,” or “GUI,” can be used in the singular or the plural to describe one or more graphical user interfaces and each of the displays of a particular graphical user interface. Therefore, a GUI can represent any graphical user interface, including but not limited to, a web browser, a touch screen, or a command line interface (CLI) that processes information and efficiently presents the information results to the user. In general, a GUI can include a number of user interface (UI) elements, some or all associated with a web browser, such as interactive fields, pull-down lists, and buttons. These and other UI elements can be related to or represent the functions of the web browser. 
     Implementations of the subject matter described in this specification can be implemented in a computing system that includes a back-end component, for example, as a data server, or that includes a middleware component, for example, an application server, or that includes a front-end component, for example, a client computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the subject matter described in this specification, or any combination of one or more such back-end, middleware, or front-end components. The components of the system can be interconnected by any form or medium of wireline or wireless digital data communication (or a combination of data communication), for example, a communication network. Examples of communication networks include a local area network (LAN), a radio access network (RAN), a metropolitan area network (MAN), a wide area network (WAN), Worldwide Interoperability for Microwave Access (WIMAX), a wireless local area network (WLAN) using, for example, 802.11 a/b/g/n or 802.20 (or a combination of 802.11x and 802.20 or other protocols consistent with the present disclosure), all or a portion of the Internet, another communication network, or a combination of communication networks. The communication network can communicate with, for example, Internet Protocol (IP) packets, frame relay frames, Asynchronous Transfer Mode (ATM) cells, voice, video, data, or other information between network nodes. 
     The computing system can include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other. 
     The foregoing and other described implementations can each, optionally, include one or more of the following features: 
     For example, in a first implementation, a computer-implemented method, including: receiving an upgrading request for an original table of an application, generating an upgraded table including a structure matching the original table, setting a session variable to initiate an application upgrade, and adding a set of triggers to the original table to selectively control read operations and write operations for the original table and the upgraded table based on the session variable. 
     The foregoing and other described implementations can each, optionally, include one or more of the following features: 
     A first feature, combinable with any of the following features, wherein the original table includes a quality original table of a quality system and the set of triggers includes writing triggers configured to copy data written to the quality original table to the upgraded table in a quality system. 
     A second feature, combinable with any of the previous or following features, further including: transporting the upgraded table from the quality system to a production system. 
     A third feature, combinable with any of the previous or following features, wherein the original table includes a production original table of the production system and the set of triggers includes reading triggers configured to perform a set of operations including: reading original data from the original table for a first type of reading requests originated from an original application of the production system, reading upgraded data from the upgraded table for a second type of reading requests originated from an upgraded application of the production system, and adding the upgraded data from the upgraded table to the production original table of the production system. 
     A fourth feature, combinable with any of the previous or following features, further including: determining an original structure of the original table. 
     A fifth feature, combinable with any of the previous or following features, further including: determining that data stored in the upgraded table includes the session variable. 
     In a second implementation, a non-transitory computer-readable storage medium coupled to one or more processors and having instructions stored thereon which, when executed by the one or more processors, cause the one or more processors to perform operations for test optimization, the operations including: receiving an upgrading request for an original table of an application, generating an upgraded table including a structure matching the original table, setting a session variable to initiate an application upgrade, and adding a set of triggers to the original table to selectively control read operations and write operations for the original table and the upgraded table based on the session variable. 
     The foregoing and other described implementations can each, optionally, include one or more of the following features: 
     A first feature, combinable with any of the following features, wherein the original table includes a quality original table of a quality system and the set of triggers includes writing triggers configured to copy data written to the quality original table to the upgraded table in a quality system. 
     A second feature, combinable with any of the previous or following features, wherein the operations further include: transporting the upgraded table from the quality system to a production system. 
     A third feature, combinable with any of the previous or following features, wherein the original table includes a production original table of the production system and the set of triggers includes reading triggers configured to perform a second set of operations including: reading original data from the original table for a first type of reading requests originated from an original application of the production system, reading upgraded data from the upgraded table for a second type of reading requests originated from an upgraded application of the production system, and adding the upgraded data from the upgraded table to the production original table of the production system. 
     A fourth feature, combinable with any of the previous or following features, further including: determining an original structure of the original table. 
     A fifth feature, combinable with any of the previous or following features, wherein the operations further include: determining that data stored in the upgraded table includes the session variable. 
     In a third implementation, a computer-implemented system, including: a client-side computing device, and a computer-readable storage device coupled to the client-side computing device and having instructions stored thereon which, when executed by the client-side computing device, cause the client-side computing device to perform operations for test optimization. The operations include: receiving an upgrading request for an original table of an application, generating an upgraded table including a structure matching the original table, setting a session variable to initiate an application upgrade, and adding a set of triggers to the original table to selectively control read operations and write operations for the original table and the upgraded table based on the session variable. 
     The foregoing and other described implementations can each, optionally, include one or more of the following features: 
     A first feature, combinable with any of the following features, wherein the original table includes a quality original table of a quality system and the set of triggers includes writing triggers configured to copy data written to the quality original table to the upgraded table in a quality system. 
     A second feature, combinable with any of the previous or following features, wherein the operations further include: transporting the upgraded table from the quality system to a production system. 
     A third feature, combinable with any of the previous or following features, wherein the original table includes a production original table of the production system and the set of triggers includes reading triggers configured to perform a second set of operations including: reading original data from the original table for a first type of reading requests originated from an original application of the production system, reading upgraded data from the upgraded table for a second type of reading requests originated from an upgraded application of the production system, and adding the upgraded data from the upgraded table to the production original table of the production system. 
     A fourth feature, combinable with any of the previous or following features, further including: determining an original structure of the original table. 
     A fifth feature, combinable with any of the previous or following features, wherein the operations further include: determining that data stored in the upgraded table includes the session variable. 
     Implementations of the subject matter and the functional operations described in this specification can be implemented in digital electronic circuitry, in tangibly embodied computer software or firmware, in computer hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them. Software implementations of the described subject matter can be implemented as one or more computer programs, that is, one or more modules of computer program instructions encoded on a tangible, non-transitory, computer-readable medium for execution by, or to control the operation of, a computer or computer-implemented system. Alternatively, or additionally, the program instructions can be encoded in/on an artificially generated propagated signal, for example, a machine-generated electrical, optical, or electromagnetic signal that is generated to encode information for transmission to a receiver apparatus for execution by a computer or computer-implemented system. The computer-storage medium can be a machine-readable storage device, a machine-readable storage substrate, a random or serial access memory device, or a combination of computer-storage mediums. Configuring one or more computers means that the one or more computers have installed hardware, firmware, or software (or combinations of hardware, firmware, and software) so that when the software is executed by the one or more computers, particular computing operations are performed. 
     The term “real-time,” “real time,” “realtime,” “real (fast) time (RFT),” “near(ly) real-time (NRT),” “quasi real-time,” or similar terms (as understood by one of ordinary skill in the art), means that an action and a response are temporally proximate such that an individual perceives the action and the response occurring substantially simultaneously. For example, the time difference for a response to display (or for an initiation of a display) of data following the individual&#39;s action to access the data can be less than 1 millisecond (ms), less than 1 second (s), or less than 5 s. While the requested data need not be displayed (or initiated for display) instantaneously, it is displayed (or initiated for display) without any intentional delay, taking into account processing limitations of a described computing system and time required to, for example, gather, accurately measure, analyze, process, store, or transmit the data. 
     The terms “data processing apparatus,” “computer,” or “electronic computer device” (or an equivalent term as understood by one of ordinary skill in the art) refer to data processing hardware. Data processing hardware encompass all kinds of apparatuses, devices, and machines for processing data, including by way of example, a programmable processor, a computer, or multiple processors or computers. The computer can also be, or further include special purpose logic circuitry, for example, a central processing unit (CPU), a field programmable gate array (FPGA), or an application-specific integrated circuit (ASIC). In some implementations, the computer or computer-implemented system or special purpose logic circuitry (or a combination of the computer or computer-implemented system and special purpose logic circuitry) can be hardware- or software-based (or a combination of both hardware- and software-based). The computer can optionally include code that creates an execution environment for computer programs, for example, code that constitutes processor firmware, a protocol stack, a database management system, an operating system, or a combination of execution environments. The present disclosure contemplates the use of a computer or computer-implemented system with an operating system of some type, for example LINUX, UNIX, WINDOWS, MAC OS, ANDROID, IOS, another operating system, or a combination of operating systems. 
     A computer program, which can also be referred to or described as a program, software, a software application, a unit, a module, a software module, a script, code, or other component can be written in any form of programming language, including compiled or interpreted languages, or declarative or procedural languages, and it can be deployed in any form, including, for example, as a stand-alone program, module, component, or subroutine, for use in a computing environment. A computer program can, but need not, correspond to a file in a file system. A program can be stored in a portion of a file that holds other programs or data, for example, one or more scripts stored in a markup language document, in a single file dedicated to the program in question, or in multiple coordinated files, for example, files that store one or more modules, sub-programs, or portions of code. A computer program can be deployed to be executed on one computer or on multiple computers that are located at one site or distributed across multiple sites and interconnected by a communication network. 
     While portions of the programs illustrated in the various figures can be illustrated as individual components, such as units or modules, that implement described features and functionality using various objects, methods, or other processes, the programs can instead include a number of sub-units, sub-modules, third-party services, components, libraries, and other components, as appropriate. Conversely, the features and functionality of various components can be combined into single components, as appropriate. Thresholds used to make computational determinations can be statically, dynamically, or both statically and dynamically determined. 
     Described methods, processes, or logic flows represent one or more examples of functionality consistent with the present disclosure and are not intended to limit the disclosure to the described or illustrated implementations, but to be accorded the widest scope consistent with described principles and features. The described methods, processes, or logic flows can be performed by one or more programmable computers executing one or more computer programs to perform functions by operating on input data and generating output data. The methods, processes, or logic flows can also be performed by, and computers can also be implemented as, special purpose logic circuitry, for example, a CPU, an FPGA, or an ASIC. 
     Computers for the execution of a computer program can be based on general or special purpose microprocessors, both, or another type of CPU. Generally, a CPU will receive instructions and data from and write to a memory. The essential elements of a computer are a CPU, for performing or executing instructions, and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to, receive data from or transfer data to, or both, one or more mass storage devices for storing data, for example, magnetic, magneto-optical disks, or optical disks. However, a computer need not have such devices. Moreover, a computer can be embedded in another device, for example, a mobile telephone, a personal digital assistant (PDA), a mobile audio or video player, a game console, a global positioning system (GPS) receiver, or a portable memory storage device. 
     Non-transitory computer-readable media for storing computer program instructions and data can include all forms of permanent/non-permanent or volatile/non-volatile memory, media and memory devices, including by way of example semiconductor memory devices, for example, random access memory (RAM), read-only memory (ROM), phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), and flash memory devices; magnetic devices, for example, tape, cartridges, cassettes, internal/removable disks; magneto-optical disks; and optical memory devices, for example, digital versatile/video disc (DVD), compact disc (CD)-ROM, DVD+/−R, DVD-RAM, DVD-ROM, high-definition/density (HD)-DVD, and BLU-RAY/BLU-RAY DISC (BD), and other optical memory technologies. The memory can store various objects or data, including caches, classes, frameworks, applications, modules, backup data, jobs, web pages, web page templates, data structures, database tables, repositories storing dynamic information, or other appropriate information including any parameters, variables, algorithms, instructions, rules, constraints, or references. Additionally, the memory can include other appropriate data, such as logs, policies, security or access data, or reporting files. The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry. 
     To provide for interaction with a user, implementations of the subject matter described in this specification can be implemented on a computer having a display device, for example, a cathode ray tube (CRT), liquid crystal display (LCD), light emitting diode (LED), or plasma monitor, for displaying information to the user and a keyboard and a pointing device, for example, a mouse, trackball, or trackpad by which the user can provide input to the computer. Input can also be provided to the computer using a touchscreen, such as a tablet computer surface with pressure sensitivity, a multi-touch screen using capacitive or electric sensing, or another type of touchscreen. Other types of devices can be used to interact with the user. For example, feedback provided to the user can be any form of sensory feedback (such as, visual, auditory, tactile, or a combination of feedback types). Input from the user can be received in any form, including acoustic, speech, or tactile input. In addition, a computer can interact with the user by sending documents to and receiving documents from a client-computing device that is used by the user (for example, by sending web pages to a web browser on a user&#39;s mobile computing device in response to requests received from the web browser). 
     The term “graphical user interface,” or “GUI,” can be used in the singular or the plural to describe one or more graphical user interfaces and each of the displays of a particular graphical user interface. Therefore, a GUI can represent any graphical user interface, including but not limited to, a web browser, a touch screen, or a command line interface (CLI) that processes information and efficiently presents the information results to the user. In general, a GUI can include a number of user interface (UI) elements, some or all associated with a web browser, such as interactive fields, pull-down lists, and buttons. These and other UI elements can be related to or represent the functions of the web browser. 
     Implementations of the subject matter described in this specification can be implemented in a computing system that includes a back-end component, for example, as a data server, or that includes a middleware component, for example, an application server, or that includes a front-end component, for example, a client computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the subject matter described in this specification, or any combination of one or more such back-end, middleware, or front-end components. The components of the system can be interconnected by any form or medium of wireline or wireless digital data communication (or a combination of data communication), for example, a communication network. Examples of communication networks include a local area network (LAN), a radio access network (RAN), a metropolitan area network (MAN), a wide area network (WAN), Worldwide Interoperability for Microwave Access (WIMAX), a wireless local area network (WLAN) using, for example, 802.11 a/b/g/n or 802.20 (or a combination of 802.11x and 802.20 or other protocols consistent with the present disclosure), all or a portion of the Internet, another communication network, or a combination of communication networks. The communication network can communicate with, for example, Internet Protocol (IP) packets, frame relay frames, Asynchronous Transfer Mode (ATM) cells, voice, video, data, or other information between network nodes. 
     The computing system can include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other. 
     While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any inventive concept or on the scope of what can be claimed, but rather as descriptions of features that can be specific to particular implementations of particular inventive concepts. Particular features that are described in this specification in the context of separate implementations can also be implemented, in combination, in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations, separately, or in any sub-combination. Moreover, although previously described features can be described as acting in particular combinations and even initially claimed as such, one or more features from a claimed combination can, in some cases, be excised from the combination, and the claimed combination can be directed to a sub-combination or variation of a sub-combination. 
     Particular implementations of the subject matter have been described. Other implementations, alterations, and permutations of the described implementations are within the scope of the following claims as will be apparent to those skilled in the art. While operations are depicted in the drawings or claims in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed (some operations can be considered optional), to achieve desirable results. In particular circumstances, multitasking or parallel processing (or a combination of multitasking and parallel processing) can be advantageous and performed as deemed appropriate. 
     Moreover, the separation or integration of various system modules and components in the previously described implementations should not be understood as requiring such separation or integration in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products. 
     Accordingly, the previously described example implementations do not define or constrain the present disclosure. Other changes, substitutions, and alterations are also possible without departing from the spirit and scope of the present disclosure. 
     Furthermore, any claimed implementation is considered to be applicable to at least a computer-implemented method; a non-transitory, computer-readable medium storing computer-readable instructions to perform the computer-implemented method; and a computer system comprising a computer memory interoperably coupled with a hardware processor configured to perform the computer-implemented method or the instructions stored on the non-transitory, computer-readable medium.