Google Inc.

Kenneth M Ashcraft

Kevin Gibbs

Jon P McAlister

Ryan C Barrett

Amit Agarwal

Jean-Michel Leon

Vishal Kasera

In an application execution system having a plurality of application servers, each application server stores a plurality of applications, and has computational resources for executing applications in response to received requests. Each application server also includes instructions for loading a respective application into volatile storage and executing the application in response to a request from a client, and for returning a result. A generic application instance may be cloned, creating a pool of generic application instance clones that can be loaded with code for a requested application to produce an application instance. The application instance can then be stored in a cache to be used for a future application request.

Application hosting in a distributed application execution system

A database server receives a request from a client application for performing a data transaction on persistent data storage. The request is sent to a set of replication servers. An acknowledgement for the request is received from each replication server, including a start sequence number and an end sequence number for data that is stored in local cache of the replication server, and a latest committed sequence number for data that was written to the persistent data storage by the replication server. A maximum value of latest committed sequence numbers received from the set of replication servers is determined. For each replication server, it is examined whether there is a gap between the start sequence number for data stored in local cache and the maximum value of the latest committed sequence numbers. Based on the examining, it is determined whether there is an occurrence of loss of data.

Database replication

A write request is received at a database server from a client application for writing data to persistent data storage. In response to receiving the write request, the database server selects a set of multiple replication servers. The data is sent from the database server to the selected set of multiple replication servers for writing to the persistent data storage. Confirmation is received at the database server from replication servers in the selected set of multiple replication servers. In response to receiving confirmation from the replication servers in the selected set of multiple replication servers, the database server sends to the client application information indicating success of the write request.

A replication server receives a first write request from a database server for writing first data to persistent data storage. The replication server determines that the first write request is designated as asynchronous. In response to determining that the first write request is asynchronous, the first data is saved to local cache at the replication server and an acknowledgement is sent to the database server. The local cache stores second data to be written to persistent data storage when the first data is saved to the local cache. The first data and the second data are written from the local cache to the persistent data storage in a batch operation.

In an application execution system having a plurality of application servers and an application master in an application execution system, the application master stores a plurality of applications, including a respective application, in a library for distribution among the application servers, adds a first instance of the respective application from the library to a respective application server for execution, and obtains usage information of one or more applications added to the application servers. In accordance with the usage information, the application master performs one of a predefined set of actions that includes: adding a second instance of the respective application to the plurality of application servers; and removing the first instance of the respective application from the respective application server.

In an application execution system having a plurality of application servers, each application server stores a plurality of applications, and has computational resources for executing applications in response to received requests. Each application server also includes instructions for loading a respective application into volatile storage and executing the application in response to a request from a client, and for returning a result. In addition, each application server includes instructions for conditionally terminating execution of the respective application prior to returning the result if the respective application violates any execution restriction. The execution restrictions may include: a response time limit; an average response time limit over multiple executions of the application; a volatile memory usage limit; a restriction on using non-volatile storage of the application server; and a requirement limiting where state information is stored. The execution restrictions in aggregate maintain scalability of the application execution system.

Application server scalability through runtime restrictions enforcement in a distributed application execution system

In an application execution system having a plurality of application servers, each application server includes non-volatile storage for storing a plurality of applications, volatile storage and computational resources for executing applications in response to requests received by the application execution system and for returning results to the requestors. In addition, each application server includes instructions for conditionally terminating execution of the respective application prior to returning the result if the respective application violates any of a plurality of execution restrictions. The execution restrictions in aggregate maintain scalability of the application execution system with respect to at least one or more of the following limits: number of applications that can be executed and number of requests that can be processed per period of time.

In a distributed application execution system having an application master and a plurality of application servers, each application server includes one or more processors and memory storing one or more programs. The one of more programs include instructions for storing in non-volatile storage a plurality of applications distributed to the application server by the application master, for loading into volatile storage and executing a respective application in response to a received request, and for returning a result to the request. In addition, the one of more programs include instructions for conditionally retaining the respective application in volatile storage, for responding to a future request, when criteria, including at least predefined usage level criteria, are met by the respective application, and otherwise removing the respective application from volatile storage upon returning the result to the request.

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Mountain View, CA, United States of America

Kenneth M Ashcraft