Abstract: Techniques and structures to facilitate automatic adjustment of a database connection pool, including calculating a first value indicating a number of connections of to be provided by a first of a plurality of application servers, determining whether the first value is equal to a second value previously calculated to indicate the number of connections to be provided by the first application server and adjusting the database connection pool by providing the number of connections to access the database as indicated by the first value upon a determination that the first value is not equal to the second value.

Abstract: An online system, such as a multi-tenant system ensures high availability of systems, for example, database management systems. The online system replicates the databases across multiple datacenters including: (1) a master node that receives read and write requests (2) a read-replica that receives only read requests and (3) a spare node that does not receive requests but acts as standby for high availability. One or more application servers may send read and write requests to the databases. The system performs a sweep of upgrades of the database nodes and also performs traffic quiescing of the requests received from the application servers to redirect the traffic across the database nodes as the upgrade sweep is orchestrated. The sweep of upgrades ensures that the availability of the database management system to the end users is maximized during the upgrade process.

Abstract: Messages are transmitted to first and second server groups in an on-demand computing services environment. The first message instructs the first server group to reduce a first resource allocation level associated with a network-accessible computing resource, while the second message instructs the second server group to increase a second resource allocation level associated with the resource. The resource allocation levels designate respective proportions of the network-accessible computing resource shared among the server groups. Request traffic associated with providing services via the on-demand computing services environment is transferred from the first server group to the second server group after decreasing the first resource allocation level and increasing the second resource allocation level.

Abstract: Techniques and structures to facilitate automatic adjustment of a database connection pool, including calculating a first value indicating a number of connections of to be provided by a first of a plurality of application servers, determining whether the first value is equal to a second value previously calculated to indicate the number of connections to be provided by the first application server and adjusting the database connection pool by providing the number of connections to access the database as indicated by the first value upon a determination that the first value is not equal to the second value

Abstract: Techniques and structures to facilitate automatic adjustment of a database connection pool, including calculating a first value indicating a number of connections of to be provided by a first of a plurality of application servers, determining whether the first value is equal to a second value previously calculated to indicate the number of connections to be provided by the first application server and adjusting the database connection pool by providing the number of connections to access the database as indicated by the first value upon a determination that the first value is not equal to the second value.

Abstract: Maintaining client version affinity during a rolling server cluster upgrade includes a server in the server cluster receiving a request from a client and checking the request for a version cookie indicating a software version that the client is running. Responsive to a determination that the server is running the same software version as the client, the server serves the request. Responsive to a determination that the client is running a software version matching a previous software version of the server, the server initiates a software upgrade on the client instead of servicing the request. Responsive to a determination that the server is not running the same software version as the client, the server forwards the request to one of the other servers in the server cluster that is running the same software version as the client.

Abstract: Techniques and structures to facilitate automatic adjustment of a database connection pool, including calculating a first value indicating a number of connections of to be provided by a first of a plurality of application servers, determining whether the first value is equal to a second value previously calculated to indicate the number of connections to be provided by the first application server and adjusting the database connection pool by providing the number of connections to access the database as indicated by the first value upon a determination that the first value is not equal to the second value

Abstract: Maintaining client version affinity during a rolling server cluster upgrade includes a server in the server cluster receiving a request from a client and checking the request for a version cookie indicating a software version that the client is running. Responsive to a determination that the server is running the same software version as the client, the server serves the request. Responsive to a determination that the client is running a software version matching a previous software version of the server, the server initiates a software upgrade on the client instead of servicing the request. Responsive to a determination that the server is not running the same software version as the client, the server forwards the request to one of the other servers in the server cluster that is running the same software version as the client.

Abstract: Maintaining client version affinity during a rolling server cluster upgrade includes a server in the server cluster receiving a request from a client and checking the request for a version cookie indicating a software version that the client is running. Responsive to a determination that the server is running the same software version as the client, the server serves the request. Responsive to a determination that the client is running a software version matching a previous software version of the server, the server initiates a software upgrade on the client instead of servicing the request. Responsive to a determination that the server is not running the same software version as the client, the server forwards the request to one of the other servers in the server cluster that is running the same software version as the client.

Abstract: Maintaining client version affinity during a rolling server cluster upgrade includes a server in the server cluster receiving a request from a client and checking the request for a version cookie indicating a software version that the client is running. Responsive to a determination that the server is running the same software version as the client, the server serves the request. Responsive to a determination that the client is running a software version matching a previous software version of the server, the server initiates a software upgrade on the client instead of servicing the request. Responsive to a determination that the server is not running the same software version as the client, the server forwards the request to one of the other servers in the server cluster that is running the same software version as the client.

Abstract: Techniques are disclosed relating to caching web application data. In some embodiments, a computing system maintains a multi-tenant database and an in-memory cache for the database. In some embodiments, the computing system is configured to store data in an entry in response to a store request and retrieve data in response to a read request. In various embodiments, data cached by one tenant is not visible to other tenants. The cache may be partitioned and each partition may have an assigned capacity. The computing system may be configured to evict cached data based on capacity thresholds, least-recently-used information, time-to-live information, amount of data in an entry, etc. The cache may indicate misses when requested data is not present. Various disclosed techniques may improve web application performance while maintaining privacy between tenants.

Abstract: Techniques are disclosed relating to an in-memory cache. In some embodiments, in response to determining that data for a requested entry is not present in the cache (e.g., because it has been evicted), a computing system is configured to invoke cached program code associated with the entry. In some embodiments, the computing system is configured to provide data generated by the program code in response to requests that indicate the entry. In some embodiments, the computing system is configured to store the generated data in the cache. In various embodiments, this may avoid cache misses and provide configurability in responding to requests to access the cache.

Abstract: Techniques are disclosed relating to an in-memory, software-managed cache configured to store web application data. In some embodiments, operations to cache data specify a visibility parameter for the data, among a plurality of namespaces. In some embodiments, requests to access cached data are checked, based on a request's namespace and the visibility parameter for the cached data, to determine whether they are allowed to proceed. In some embodiments, this may facilitate caching data using shared computing systems and data structures while maintaining configurable privacy for cached data.

Abstract: Techniques are disclosed relating to an in-memory cache for web application data. In some embodiments, received transactions include multiple operations, including one or more cache operations to access the in-memory cache. In some embodiments, transactions are performed atomically. In some embodiments, data for the one or more cache operations is stored locally in memory by an application server outside of the in-memory cache until the transaction is successfully completed. This may improve performance and facilitate atomicity, in some embodiments.

Abstract: Techniques are disclosed relating to caching web application data. In some embodiments, a computing system maintains a multi-tenant database and an in-memory cache for the database. In some embodiments, the computing system is configured to store data in an entry in response to a store request and retrieve data in response to a read request. In various embodiments, data cached by one tenant is not visible to other tenants. The cache may be partitioned and each partition may have an assigned capacity. The computing system may be configured to evict cached data based on capacity thresholds, least-recently-used information, time-to-live information, amount of data in an entry, etc. The cache may indicate misses when requested data is not present. Various disclosed techniques may improve web application performance while maintaining privacy between tenants.

Abstract: Techniques are disclosed relating to an in-memory cache. In some embodiments, in response to determining that data for a requested entry is not present in the cache (e.g., because it has been evicted), a computing system is configured to invoke cached program code associated with the entry. In some embodiments, the computing system is configured to provide data generated by the program code in response to requests that indicate the entry. In some embodiments, the computing system is configured to store the generated data in the cache. In various embodiments, this may avoid cache misses and provide configurability in responding to requests to access the cache.

Abstract: Techniques are disclosed relating to an in-memory, software-managed cache configured to store web application data. In some embodiments, operations to cache data specify a visibility parameter for the data, among a plurality of namespaces. In some embodiments, requests to access cached data are checked, based on a request's namespace and the visibility parameter for the cached data, to determine whether they are allowed to proceed. In some embodiments, this may facilitate caching data using shared computing systems and data structures while maintaining configurable privacy for cached data.

Abstract: Techniques are disclosed relating to an in-memory cache for web application data. In some embodiments, received transactions include multiple operations, including one or more cache operations to access the in-memory cache. In some embodiments, transactions are performed atomically. In some embodiments, data for the one or more cache operations is stored locally in memory by an application server outside of the in-memory cache until the transaction is successfully completed. This may improve performance and facilitate atomicity, in some embodiments.