Patent Application
20110265069
A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.
Embodiments described herein relate generally to evaluation of bytecode in a database network system. More particularly, embodiments described herein relate to efficient utilization of shared resources for evaluation of bytecode.
The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized. The subject matter in the background section merely represents different approaches.
In conventional database systems, users access their data resources in one logical database. A user of such a conventional system typically retrieves data from and stores data on the system using the user's own systems. A user system might remotely access one of a plurality of server systems that might in turn access the database system. Data retrieval from the system might include the issuance of a query from the user system to the database system. The database system might process the request for information received in the query and send to the user system information relevant to the request.
As an on demand platform, Apex™ provides a set of features for building business applications including, for example, data models and objects to manage data, a workflow engine for managing collaboration of that data, a user interface model to handle forms and other interactions, and a Web services application programming interface (API) for programmatic access and integration. These platform technologies support custom applications and integrations, and allow developers to build applications utilizing this on demand model.
Apex code is “on demand,” running without requiring local servers or software. Apex code may run in a multi-tenant environment, providing the economic and manageability benefits of a shared service while keeping the definition, data and behavior of each customer's application separate from each other. For developers, the combination of these capabilities with this on-demand, multi-tenant delivery provides convenience, scalability, and safety of an on-demand database, combined with the flexibility and control of a procedural language.
Apex code provides a powerful and productive approach to creating functionality and logic, allowing developers to focus on elements specific to their application, while leaving other elements to the platform's framework. Apex code is a successful and innovative language in part because of its multi-tenant design. Multitenancy allows Apex to scale to a large number of customers with a relatively modest hardware investment. Apex code is abstracted and governed, utilizing only as many resources as is allowed.
Performance is a key requirement for any programming language. It is especially important in a multitenant environment where processor cycles spent interpreting code for a given customer have a direct and negative impact on other customers sharing the same environment. Thus, improving performance not only results in quicker response times for users but also less impact on other tenants in terms of the overall load on the system.
All languages tend to have some start-up cost associated with getting code into a state where it can be executed. This cost includes, for example, the processing required to load the executable form of the code and to link it with dependent code. Unlike most programming languages, however, start-up costs tend to dominate in a multi-tenant language where the interpreter may be called upon to execute code from any one of possibly thousands of tenants. The ability to cache executable code to avoid the start-up costs on subsequent requests is limited by the large working set. In addition, the requests tend to be relatively short, making the start-up cost a larger proportion of the overall request time.
In the following drawings like reference numbers are used to refer to like elements. Although the following figures depict various examples, the invention is not limited to the examples depicted in the figures.
In the following description, numerous specific details are set forth. However, embodiments may be practiced without these specific details. In other instances, well-known circuits, structures and techniques have not been shown in detail in order not to obscure the understanding of this description.
As used herein, the term multi-tenant database system refers to those systems in which various elements of hardware and software of the database system may be shared by one or more customers. For example, a given application server may simultaneously process requests for a great number of customers, and a given database table may store rows for a potentially much greater number of customers.
In one embodiment, a multi-tenant database system utilizes tenant identifiers (IDs) within a multi-tenant environment to allow individual tenants to access their data while preserving the integrity of other tenant's data. In one embodiment, the multitenant database stores data for multiple client entities each identified by a tenant ID having one of one or more users associated with the tenant ID. Users of each of multiple client entities can only access data identified by a tenant ID associated with their respective client entity. In one embodiment, the multitenant database is a hosted database provided by an entity separate from the client entities, and provides on-demand and/or real-time database service to the client entities.
As used herein, the term bytecode refers to various forms of instruction sets to be executed by a software interpreter. Bytecode instructions are also suitable for further compilation into machine code. Bytecode instructions are processed by software, but have similarities to hardware instructions. Virtual stack machines are common execution environments. A bytecode program may be executed by parsing instructions and directly executing the instructions, one at a time. Some systems, called dynamic translators, or “just-in-time” (JIT) compilers, translate bytecode into machine language as necessary at runtime.
The users of each of the multiple client entities can only access data identified by a tenant ID associated with the respective client entity. In one embodiment, multitenant database 100 is a hosted database provided by an entity separate from the client entities, and provides on-demand database service to the client entities. Multitenant database 100 further includes shared database engine 120 that provides the functionality of multitenant database 100 in operating on tenant data sets 110.
The multitenant environment further includes multitenant code 150, which includes multiple tenant logic sets 160 corresponding to the tenants of the multitenant environment. In one embodiment, multitenant code 150 includes code for multiple client entities each identified by the corresponding tenant IDs. The users of each of the multiple client entities can only access code identified by the tenant ID associated with the respective client entity. In one embodiment, multitenant code 150 is stored in a hosted database provided by an entity separate from the client entities, and provides on-demand database service to the client entities. Multitenant code 150 further includes shared execution engine 170 that provides the ability to execute code represented by multitenant code 150. In one embodiment, shared execution engine 170 is a virtual machine.
In one embodiment, Apex is implemented as an Abstract Syntax Tree (AST)-based interpreter. Most compilers parse source code into an intermediate AST form. An AST interpreter executes directly on the generated AST in order to interpret the code. A full source code parse is required to compute the AST. Thus, parsing the Apex source code is expensive.
To reduce this parsing cost, the Apex runtime caches the generated AST in memcached. The term “memcached” refers to a general-purpose distributed memory caching system often used to speed up dynamic database-driven applications or websites by caching data and objects in system memory to reduce the number of times an external data source (such as a database or API) must be read. Memcached runs on Unix, Windows and MacOS.
Storage of the AST in memcached requires the AST to be serialized into a byte stream. The AST is comprised of a set of nodes, each representing some construct in the source code (e.g., a while loop, an add expression, etc.). The set of nodes can become fairly large, for example, it can be approximately 10.5 times the source code size in terms of heap consumption. In addition, this size consists of a very large number of very small Java™ or other bytecode objects. Unfortunately, very large object graphs are expensive to serialize using Java serialization techniques. Deserializing the AST from memcached is the dominant cost in many Apex requests. Java is a trademark of Sun Microsystems.
In one embodiment, the Apex interpreter serves as a level of isolation between customer code and the host virtual machine (VM). The Apex interpreter may enforce governor limits and brokers requests to the underlying platform on behalf of customer code. In one embodiment, the Apex interpreter is not a full-fledged Java virtual machine. The Apex interpeter may delegate to the real Java virtual machine (JVM) for various services. Garbage collection is an example of this. In one embodiment, the Apex interpreter is also able to delegate to the real JVM on a per type basis.
A memory space is established, 210. In a multitenant environment, a tenant may be provided with one or more secure portions of memory to execute that tenant's code. In one embodiment, the tenant ID is utilized to determine authorization to access a memory location.
Code to be executed in the memory space is retrieved from the multitenant database, 220. In one embodiment, the code is source code that will be compiled. In another embodiment, the retrieved code may be executable code, for example, bytecode. If the retrieved code has not yet been compiled, the retrieved code is compiled, 230.
In one embodiment, when the source code is compiled, one or more resource limiter enforcement (or governor) mechanisms are included in the code at compile time, 230. Multiple types of limiting mechanisms can be included in the compiled code. By providing limiting mechanisms in the compiled code, the resulting compiled code can be self-limiting (or self-managing), which may result in a more secure and/or more efficient system.
One type of limiting mechanism that may be utilized is a synchronous governor. The synchronous governor may monitor one or more performance characteristics (e.g., processor usage, memory usage, bandwidth utilization) at pre-selected intervals.
Another type of limiting mechanism that may be utilized is an interrupt-based governor. Interrupt-based governing results from an interrupt trigger being placed in the compiled code. In response to an interrupt, the interrupt service routine monitors one or more performance characteristics (e.g., processor usage, memory usage, bandwidth utilization). Interrupt-based governing allows the evaluation to be performed outside the memory space established for the code. This may result in a more secure enforcement.
Another type of limiting mechanism is use of a self-incrementing counter that is incremented by and evaluated by the compiled code during execution. That is, each time a monitored operation is performed, a corresponding counter is incremented (or decremented) to monitor use of an associated resource. Various combinations of incrementing and/or decrementing counters can be utilized as the code is executed to provide the desired level of monitoring and enforcement.
The compiled code is executed, 240. During execution, one or more limit triggers may be encountered, 250. The code is executed until a limit trigger is encountered, 240, 250. The limit triggers correspond to the monitoring mechanisms described above. For example, during execution, an interrupt may be triggered by execution of the bytecode. In response to the limit trigger, 250, an evaluation is performed, 260, to determine if the monitored characteristic is over the corresponding limit.
If the monitored characteristic is not over the corresponding limit, 260, the code may be allowed to continue execution, 240. If the monitored characteristic is over the corresponding limit, 260, the execution of the code may be halted or torn down, 270. Thus, source code may be compiled to provide full or partial self monitoring of resource utilization that may result in early termination of the code if designated resource limits are exceeded.
Environment 310 is an environment in which an on-demand database service exists. User system 312 may be any machine or system that is used by a user to access a database user system. For example, any of user systems 312 can be a handheld computing device, a mobile phone, a laptop computer, a work station, and/or a network of computing devices. As illustrated in
An on-demand database service, such as system 316, is a database system that is made available to outside users that do not need to necessarily be concerned with building and/or maintaining the database system, but instead may be available for their use when the users need the database system (e.g., on the demand of the users). Some on-demand database services may store information from one or more tenants stored into tables of a common database image to form a multi-tenant database system (MTS). Accordingly, “on-demand database service 316” and “system 316” will be used interchangeably herein.
A database image may include one or more database objects. A relational database management system (RDMS) or the equivalent may execute storage and retrieval of information against the database object(s). Application platform 318 may be a framework that allows the applications of system 316 to run, such as the hardware and/or software, e.g., the operating system. In an embodiment, on-demand database service 316 may include an application platform 318 that enables creation, managing and executing one or more applications developed by the provider of the on-demand database service, users accessing the on-demand database service via user systems 312, or third party application developers accessing the on-demand database service via user systems 312.
The users of user systems 312 may differ in their respective capacities, and the capacity of a particular user system 312 might be entirely determined by permissions (permission levels) for the current user. For example, where a salesperson is using a particular user system 312 to interact with system 316, that user system has the capacities allotted to that salesperson. However, while an administrator is using that user system to interact with system 316, that user system has the capacities allotted to that administrator. In systems with a hierarchical role model, users at one permission level may have access to applications, data, and database information accessible by a lower permission level user, but may not have access to certain applications, database information, and data accessible by a user at a higher permission level. Thus, different users will have different capabilities with regard to accessing and modifying application and database information, depending on a user's security or permission level.
Network 314 is any network or combination of networks of devices that communicate with one another. For example, network 314 can be any one or any combination of a LAN (local area network), WAN (wide area network), telephone network, wireless network, point-to-point network, star network, token ring network, hub network, or other appropriate configuration. As the most common type of computer network in current use is a TCP/IP (Transfer Control Protocol and Internet Protocol) network, such as the global internetwork of networks often referred to as the “Internet” with a capital “I,” that network will be used in many of the examples herein. However, it should be understood that the networks are not so limited, although TCP/IP is a frequently implemented protocol.
User systems 312 might communicate with system 316 using TCP/IP and, at a higher network level, use other common Internet protocols to communicate, such as HTTP, FTP, AFS, WAP, etc. In an example where HTTP is used, user system 312 might include an HTTP client commonly referred to as a “browser” for sending and receiving HTTP messages to and from an HTTP server at system 316. Such an HTTP server might be implemented as the sole network interface between system 316 and network 314, but other techniques might be used as well or instead. In some implementations, the interface between system 316 and network 314 includes load sharing functionality, such as round-robin HTTP request distributors to balance loads and distribute incoming HTTP requests evenly over a plurality of servers. At least as for the users that are accessing that server, each of the plurality of servers has access to the MTS' data; however, other alternative configurations may be used instead.
In one embodiment, system 316, shown in
With a multi-tenant system, data for multiple tenants may be stored in the same physical database object, however, tenant data typically is arranged so that data of one tenant is kept logically separate from that of other tenants so that one tenant does not have access to another tenant's data, unless such data is expressly shared. In certain embodiments, system 316 implements applications other than, or in addition to, a CRM application. For example, system 16 may provide tenant access to multiple hosted (standard and custom) applications, including a CRM application. User (or third party developer) applications, which may or may not include CRM, may be supported by the application platform 318, which manages creation, storage of the applications into one or more database objects and executing of the applications in a virtual machine in the process space of the system 316.
One arrangement for elements of system 316 is shown in
Several elements in the system shown in
Each user system 312 also typically includes one or more user interface devices, such as a keyboard, a mouse, trackball, touch pad, touch screen, pen or the like, for interacting with a graphical user interface (GUI) provided by the browser on a display (e.g., a monitor screen, LCD display, etc.) in conjunction with pages, forms, applications and other information provided by system 316 or other systems or servers. For example, the user interface device can be used to access data and applications hosted by system 316, and to perform searches on stored data, and otherwise allow a user to interact with various GUI pages that may be presented to a user. As discussed above, embodiments are suitable for use with the Internet, which refers to a specific global internetwork of networks. However, it should be understood that other networks can be used instead of the Internet, such as an intranet, an extranet, a virtual private network (VPN), a non-TCP/IP based network, any LAN or WAN or the like.
According to one embodiment, each user system 312 and all of its components are operator configurable using applications, such as a browser, including computer code run using a central processing unit such as an Intel Pentium® processor or the like. Similarly, system 316 (and additional instances of an MTS, where more than one is present) and all of their components might be operator configurable using application(s) including computer code to run using a central processing unit such as processor system 317, which may include an Intel Pentium® processor or the like, and/or multiple processor units.
A computer program product embodiment includes a machine-readable storage medium (media) having instructions stored thereon/in which can be used to program a computer to perform any of the processes of the embodiments described herein. Computer code for operating and configuring system 316 to intercommunicate and to process webpages, applications and other data and media content as described herein are preferably downloaded and stored on a hard disk, but the entire program code, or portions thereof, may also be stored in any other volatile or non-volatile memory medium or device as is well known, such as a ROM or RAM, or provided on any media capable of storing program code, such as any type of rotating media including floppy disks, optical discs, digital versatile disk (DVD), compact disk (CD), microdrive, and magneto-optical disks, and magnetic or optical cards, nanosystems (including molecular memory ICs), or any type of media or device suitable for storing instructions and/or data.
Additionally, the entire program code, or portions thereof, may be transmitted and downloaded from a software source over a transmission medium, e.g., over the Internet, or from another server, as is well known, or transmitted over any other conventional network connection as is well known (e.g., extranet, VPN, LAN, etc.) using any communication medium and protocols (e.g., TCP/IP, HTTP, HTTPS, Ethernet, etc.) as are well known. It will also be appreciated that computer code for implementing embodiments described herein can be implemented in any programming language that can be executed on a client system and/or server or server system such as, for example, C, C++, HTML, any other markup language, Java™, JavaScript, ActiveX, any other scripting language, such as VBScript, and many other programming languages as are well known may be used. (Java™ is a trademark of Sun Microsystems, Inc.).
According to one embodiment, each system 316 is configured to provide webpages, forms, applications, data and media content to user (client) systems 312 to support the access by user systems 312 as tenants of system 316. As such, system 316 provides security mechanisms to keep each tenant's data separate unless the data is shared. If more than one MTS is used, they may be located in close proximity to one another (e.g., in a server farm located in a single building or campus), or they may be distributed at locations remote from one another (e.g., one or more servers located in city A and one or more servers located in city B).
As used herein, each MTS could include one or more logically and/or physically connected servers distributed locally or across one or more geographic locations. Additionally, the term “server” is meant to include a computer system, including processing hardware and process space(s), and an associated storage system and database application (e.g., OODBMS or RDBMS). It should also be understood that “server system” and “server” are often used interchangeably herein. Similarly, the database object described herein can be implemented as single databases, a distributed database, a collection of distributed databases, a database with redundant online or offline backups or other redundancies, etc., and might include a distributed database or storage network and associated processing intelligence.
User system 312, network 314, system 316, tenant data storage 322, and system data storage 324 were discussed above in
As shown by
Application platform 318 includes an application setup mechanism 438 that supports application developers' creation and management of applications, which may be saved as metadata into tenant data storage 322 by save routines 436 for execution by subscribers as one or more tenant process spaces 404 managed by tenant management process 410 for example. Invocations to such applications may be coded using PL/SOQL 434 that provides a programming language style interface extension to API 432. A detailed description of some PL/SOQL language embodiments is discussed in commonly owned co-pending U.S. Provisional Patent Application 60/828,192 entitled, PROGRAMMING LANGUAGE METHOD AND SYSTEM FOR EXTENDING APIS TO EXECUTE IN CONJUNCTION WITH DATABASE APIS, by Craig Weissman, filed Oct. 4, 2006, which is incorporated in its entirety herein for all purposes. Invocations to applications may be detected by one or more system processes, which manages retrieving application metadata 416 for the subscriber making the invocation and executing the metadata as an application in a virtual machine.
Each application server 400 may be communicably coupled to database systems, e.g., having access to system data 325 and tenant data 323, via a different network connection. For example, one application server 4001 might be coupled via the network 314 (e.g., the Internet), another application server 400N-1 might be coupled via a direct network link, and another application server 400N might be coupled by yet a different network connection. Transfer Control Protocol and Internet Protocol (TCP/IP) are typical protocols for communicating between application servers 400 and the database system. However, it will be apparent to one skilled in the art that other transport protocols may be used to optimize the system depending on the network interconnect used.
In certain embodiments, each application server 400 is configured to handle requests for any user associated with any organization that is a tenant. Because it is desirable to be able to add and remove application servers from the server pool at any time for any reason, there is preferably no server affinity for a user and/or organization to a specific application server 400. In one embodiment, therefore, an interface system implementing a load balancing function (e.g., an F5 Big-IP load balancer) is communicably coupled between the application servers 400 and the user systems 312 to distribute requests to the application servers 400. In one embodiment, the load balancer uses a least connections algorithm to route user requests to the application servers 400. Other examples of load balancing algorithms, such as round robin and observed response time, also can be used. For example, in certain embodiments, three consecutive requests from the same user could hit three different application servers 400, and three requests from different users could hit the same application server 400. In this manner, system 316 is multi-tenant, wherein system 316 handles storage of, and access to, different objects, data and applications across disparate users and organizations.
As an example of storage, one tenant might be a company that employs a sales force where each salesperson uses system 316 to manage their sales process. Thus, a user might maintain contact data, leads data, customer follow-up data, performance data, goals and progress data, etc., all applicable to that user's personal sales process (e.g., in tenant data storage 322). In an example of a MTS arrangement, since all of the data and the applications to access, view, modify, report, transmit, calculate, etc., can be maintained and accessed by a user system having nothing more than network access, the user can manage his or her sales efforts and cycles from any of many different user systems. For example, if a salesperson is visiting a customer and the customer has Internet access in their lobby, the salesperson can obtain critical updates as to that customer while waiting for the customer to arrive in the lobby.
While each user's data might be separate from other users' data regardless of the employers of each user, some data might be organization-wide data shared or accessible by a plurality of users or all of the users for a given organization that is a tenant. Thus, there might be some data structures managed by system 316 that are allocated at the tenant level while other data structures might be managed at the user level. Because an MTS might support multiple tenants including possible competitors, the MTS should have security protocols that keep data, applications, and application use separate. Also, because many tenants may opt for access to an MTS rather than maintain their own system, redundancy, up-time, and backup are additional functions that may be implemented in the MTS. In addition to user-specific data and tenant specific data, system 316 might also maintain system level data usable by multiple tenants or other data. Such system level data might include industry reports, news, postings, and the like that are sharable among tenants.
In certain embodiments, user systems 312 (which may be client systems) communicate with application servers 400 to request and update system-level and tenant-level data from system 316 that may require sending one or more queries to tenant data storage 322 and/or system data storage 324. System 316 (e.g., an application server 400 in system 316) automatically generates one or more SQL statements (e.g., one or more SQL queries) that are designed to access the desired information. System data storage 324 may generate query plans to access the requested data from the database.
Each database can generally be viewed as a collection of objects, such as a set of logical tables, containing data fitted into predefined categories. A “table” is one representation of a data object, and may be used herein to simplify the conceptual description of objects and custom objects. It should be understood that “table” and “object” may be used interchangeably herein. Each table generally contains one or more data categories logically arranged as columns or fields in a viewable schema. Each row or record of a table contains an instance of data for each category defined by the fields. For example, a CRM database may include a table that describes a customer with fields for basic contact information such as name, address, phone number, fax number, etc. Another table might describe a purchase order, including fields for information such as customer, product, sale price, date, etc. In some multi-tenant database systems, standard entity tables might be provided for use by all tenants. For CRM database applications, such standard entities might include tables for Account, Contact, Lead, and Opportunity data, each containing pre-defined fields. It should be understood that the word “entity” may also be used interchangeably herein with “object” and “table”.
In some multi-tenant database systems, tenants may be allowed to create and store custom objects, or they may be allowed to customize standard entities or objects, for example by creating custom fields for standard objects, including custom index fields. U.S. patent application Ser. No. 10/817,161, filed Apr. 2, 2004, entitled “Custom Entities and Fields in a Multi-Tenant Database System”, and which is hereby incorporated herein by reference, teaches systems and methods for creating custom objects as well as customizing standard objects in a multi-tenant database system. In certain embodiments, for example, all custom entity data rows are stored in a single multi-tenant physical table, which may contain multiple logical tables per organization. It is transparent to customers that their multiple “tables” are in fact stored in one large table or that their data may be stored in the same table as the data of other customers.
Reference in the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment.
While the invention has been described by way of example and in terms of the specific embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements as would be apparent to those skilled in the art. Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.
This application claims the benefit of U.S. Provisional Patent Application 61/326,368 entitled METHODS AND SYSTEMS FOR EVALUATING BYTECODE IN AN ON-DEMAND SERVICE ENVIRONMENT INCLUDING EFFICIENT UTILIZATION OF SHARED RESOURCES AND GOVERNOR LIMIT ENFORCEMENT, by Gregory D. Fee and William J. Gallagher, filed Apr. 21, 2010 (Attorney Docket No. P001Z1), the entire contents of which are incorporated herein by reference. This application claims the benefit of U.S. Provisional Patent Application 61/326,377 entitled METHODS AND SYSTEMS FOR EVALUATING BYTECODE IN AN ON-DEMAND SERVICE ENVIRONMENT INCLUDING TRANSLATION OF APEX TO BYTECODE, by Gregory D. Fee and William J. Gallagher, filed Apr. 21, 2010 (Attorney Docket No. P001Z2), the entire contents of which are incorporated herein by reference. This application claims the benefit of U.S. Provisional Patent Application 61/326,385 entitled METHODS AND SYSTEMS FOR EVALUATING BYTECODE IN AN ON-DEMAND SERVICE ENVIRONMENT INCLUDING PROVIDING A MULTI-TENANT, MULTI-LANGUAGE RUNTIME ENVIRONMENTS AND SYSTEMS, by Gregory D. Fee and William J. Gallagher, filed Apr. 21, 2010 (Attorney Docket No. P001Z3), the entire contents of which are incorporated herein by reference. The following commonly owned, co-pending United States patents and patent applications, including the present application, are related to each other. Each of the other patents/applications are incorporated by reference herein in its entirety: U.S. patent application Ser. No. 12/______, entitled “METHODS AND SYSTEMS FOR EVALUATING BYTECODE IN AN ON-DEMAND SERVICE ENVIRONMENT INCLUDING TRANSLATION OF APEX TO BYTECODE,” by Gregory D. Fee and William J. Gallagher, filed ______, 2010 (Attorney Docket No. P001-B); and U.S. patent application Ser. No. 12/______, entitled “METHODS AND SYSTEMS FOR UTILIZING BYTECODE IN AN ON-DEMAND SERVICE ENVIRONMENT INCLUDING PROVIDING A MULTI-TENANT, MULTI-LANGUAGE RUNTIME ENVIRONMENTS AND SYSTEMS,” by Gregory D. Fee and William J. Gallagher, filed ______, 2010 (Attorney Docket No. P001-C).
| Number | Date | Country | |
|---|---|---|---|
| 61326385 | Apr 2010 | US | |
| 61326368 | Apr 2010 | US | |
| 61326377 | Apr 2010 | US |
