Abstract: A database management system receives a request to create an index for a virtual view of a database table. In response to the request, the database management system identifies relationships between the columns of the virtual view and columns of the database table. The database management system generates an index on the database table, where columns are included in the generated index based on the identified relationships and the definition of the virtual view. Queries of the virtual view are assisted by the generated index of the underlying table.

Abstract: A journaled database may comprise a computing node that forms a local version of a global state, synchronized with respect to the high-water mark of a data node that maintains the global state. Instructions to modify the state that have been committed, subsequent to forming the local version of the state, may be represented in a merge signature. An uncommitted transaction may be checked for conflicts with respect to a last-ordered committed instruction to modify the data state. Validation with respect to earlier instructions represented by the merge signature may be skipped.

Abstract: A provider network provides task capture and execution for tasks performed with respect to resources in the provider network. Task actions performed with respect to resources may be captured based on inputs to a provider network via a network-based service for the provider network in order to generate a recorded task. The recorded task may be stored for subsequent execution. In response to the detection of an execution event for the recorded task, the task actions may be performed as described in the recorded task. In some embodiments, task parameters and execution events may be defined for recorded tasks. Multiple recorded tasks may be linked together to be managed and executed as recorded task workflows. Recorded tasks may also be obtained that were recorded by other clients, or recorded for different provider networks.

Abstract: A database management system stores data for a table as a journal of transaction. The records of the journal comprise information indicative of changes applied to a document of the table. The database receives a query on a table of transactions performed on the table. In response to the query on the table of transactions, the database generates results by retrieving and projecting the records of the journal in accordance with the query. The results of the query are indicative of changes applied to the document of the table.

Abstract: A control-plane component of a network-accessible service receives an indication that a resource request has been submitted by a client. The component determines, based at least in part on metadata associated with the client, that a first parameter selection policy (PSP) of one or more PSPs created for the service is applicable. The first PSP includes a condition set to determine applicability, and a value set indicating parameter values to be used to fulfill resource requests to which the PSP applies. Using the value set, an effective parameter value list for one or more operations to be performed to allocate the requested resource is generated, and the allocation operations are initiated.

Abstract: A data store manager of a multi-data-store storage system detects an error condition associated with applying a state change indicated in a particular journal entry of the storage system to a first data store. A first redaction entry inserted in the journal at some point after the particular entry is identified. The first redaction entry indicates the particular entry as a redaction target. After verifying that the journal does not include another redaction entry targeting the first redaction entry, processing of the particular entry is terminated and processing of later-inserted entries can proceed.

Abstract: A snapshot manager examines a set of entries of a journal of a multi-data-store storage system. Each entry is formatted in a data-store-independent transaction language and various entries contain a respective indication of a committed change to a data object or to a journal schema. Corresponding to various data objects that are materialized at least at a data store of the storage system, respective compact state change representations are generated based on the set of journal entries affecting the data objects. A given compact state change representation, also formatted in the transaction language, may represent cumulative effects of several changes. A snapshot of the journal, comprising the compact state representations, is stored.

Abstract: A journal service maintains a journal that holds a number of journal entries. Access to the journal entries is controlled by providing a lead resource with access to a named role associated with the journal. A pool of alternate resources containing potential replacements for the lead resource is maintained. A succession order may be established for the pool of alternate resources, and individual resources in the pool of alternate resources may be managed based at least in part on their position within the succession order. The succession order may be established using various criteria that are indicative of a likelihood that a particular alternate resource will be available if the lead resource fails, such as the presence of shared points of failure between the current lead resource and an alternate resource. The lead resource may be replaced with an alternate resource as a result of various impeachment events.

Abstract: A repeater system for relaying wireless communications between a base station and one or more devices having: a repeater to relay network information from a base station to one or more devices; a donor antenna configured to receive and/or transmit network information between the repeater and the base station; a power supply external to the repeater; and, a server antenna integrated with the power supply, the server antenna configured to receive and/or transmit network information between the repeater and the one or more devices.

Abstract: A service workflow agent associated with a particular service of a provider network identifies a repository in which workflow descriptors indicative of tasks to be performed by the service are stored. In response to determining that a modification has been applied at one such repository, the agent examines a particular workflow descriptor stored in the repository. The agent initiates an attempt to implement a first task indicated in the descriptor. Subsequently, the agent updates the descriptor in accordance with an optimistic concurrency control technique to indicate a status of the first task.

Abstract: A database management system receives a request to perform a transaction. The database management system commits the transaction, and in response to committing the transaction, generates a cryptographic hash based on an attribute of the transaction. The cryptographic hash is stored in a leaf-region of a hash tree. In response to a request to verify the transaction, signatures are retrieved from the tree based on a traversal of the tree to locate the node corresponding to the transaction. The retrieved signatures are used to verify the transaction.

Abstract: A database management system receives a request to create an index for a virtual view of a database table. In response to the request, the database management system identifies relationships between the columns of the virtual view and columns of the database table. The database management system generates an index on the database table, where columns are included in the generated index based on the identified relationships and the definition of the virtual view. Queries of the virtual view are assisted by the generated index of the underlying table.

Abstract: A journal service manages a journal that holds a number of journal entries. Journal entries are provided to the journal service by one or more producer services, and the journal service provides journal entries to one or more consumer services. Lead consumers retrieve journal entries from the journal service by specifying a named cursor which identifies a location within the journal from which the journal entries are retrieved. The journal service may select a lead producer and a lead consumer from a collection of candidate producers and consumers using a fitness score determined for each candidate producer and consumer. The fitness score may be based at least in part on the processing capability, predicted reliability, and cost of each candidate producer and consumer. The journal service may replace a lead consumer or producer with an alternate consumer or producer in response to a variety of events.

Abstract: A client-side component of a journal-based multi-data-store database identifies an application schema corresponding to a first application whose data is stored at the database. The application schema includes a writes section indicating a data object to which writes are to be issued from the first application. A journal schema defining one or more data objects for which a concurrency-control protocol is implemented by a journal manager of the database is obtained. Before a transaction request of the application is submitted to the journal manager, the client-side component verifies that the application schema is compatible with the journal schema.

Abstract: A database table, such as may be implemented by a non-relational database, is provided to present information and states associated with that information as memorialized in a cryptographically secured ledger. The semantics of the database table elements, as well as the relationships between various objects therein, may be defined and/or enforced by a schema, a database engine, and/or an application layer. For example, the disclosed methods and systems may be used to implement an asset tracking tool that does not require trust of the implementing system for verification of the system's contents.

Abstract: Technologies are disclosed for improving the availability of a distributed application by computing scores for the application that indicate the extent to which the configuration of hosts implementing the application complies with best practices for maximizing availability. One score can be generated for the application based upon the physical location of the hosts used to implement the application and the components upon which the application is dependent. Another score can be generated for the application based upon the number of data centers that hosts executing the application are located in as compared to a minimum required number of data centers. Another score can be generated for the application based upon the distribution of hosts utilized to execute the application across data centers. Operations can be initiated for improving the scores, such as migrating a host to a new rack or server, or migrating a host to a different data center.

Abstract: Systems, methods and computer-readable media are described for pre-warming compute instances in datacenters. A service provider associated with the datacenters may expect a demand for the compute instances and pre-configure computing resources within the datacenters to pre-launch the compute instances. As such, when a user requests a compute instance, the service provider may satisfy the request by allocating a pre-warmed compute instance to the user.

Abstract: Users intending to launch instances or otherwise access virtual resources in a multi-tenant environment can specify a launch configuration. For each type of instance or each type of user, at least one launch configuration is created that includes parameters and values to be used in instantiating an instance of that type, the values being optimized for the current environment and type of instance. Launch configurations can be optimized for different types of users, such as to account for security credentials and access levels. Such an approach enables users to launch instances by contacting the resource provider directly without need for a proxy, which can function as a choke point under heavy load. The use of an appropriate launch configuration can be enforced for any type of user at any level, such as at the sub-net level, by modifying a request that does not specify an appropriate launch configuration.

Abstract: A resource manager arranges the resources in a computer system into one or more resource pools. The resource manager allocates a number of active resources and a number of backup resources to a particular resource pool. For each resource managed by the resource manager, the resource manager acquires information that describes the capacity and reliability of the resource. Capacity and reliability information for the particular resource pool is determined based on the capacity and reliability information associated with the resources assigned to the pool. In response to a request, the resource manager may provide an application with resources from several resource pools. The likelihood that the resource manager will be able to provide sufficient resources to the application may be determined based at least in part on the reliability information associated with the several resource pools.

Abstract: A partitioning policy for materializing writes indicated in journal entries of a multi-data-store database is determined. The policy indicates a partitioning attribute of a data object. A write applier associated with a materialization node of the database processes journal entries according to the partitioning policy. If the value of the partitioning attribute associated with a write of a particular journal entry indicates that the write belongs to a partition materialized at the materialization node, the write applier propagates the write to the materialization node for storage at the node's storage devices.