Abstract: A storage node of a database replica group may distribute different portions of data in local storage and external storage, where local storage and external storage are organized using different types of index structures. Responsive to receiving an access request for a database, a storage node may determine that an item of the database to be accessed by the request does not reside within a first portion of the database stored locally at the storage node. Responsive to this determination, the storage node may obtain from an external storage service a second portion of the database, the second portion including a plurality of items including the item, and the second portion organized according to a structure different from the first portion. The storage node may then store the plurality of obtained items in the first portion and process the request using the first portion of the database.

Abstract: A data store maintains a collection of data using a log-based storage structure. In response to a request to delete an item from the collection, the database management system adds a tombstone entry to the log-based storage structure, with additional metadata associated with the tombstone. Access to the tombstone metadata is provided to a client of the data store. The tombstone is deleted from the log-based storage structure after expiry of a time-to-live period.

Abstract: Techniques are described for enabling a database service to provide a zonal consistency model for read and write operations involving database tables replicated across a plurality of availability zones of a cloud provider network according to some embodiments. A database service routes zonally consistent operations to request routers and storage nodes that are located in a same availability zone as the client device from which the request originates. For example, in contrast to standard write operations and strongly consistent read operations, which are processed by a leader storage node that may be located in a different availability zone than the originating request, zonally consistent operations can be processed by any storage node and, in particular, by a storage node in a same availability zone as the originating client device.

Abstract: Various embodiments are described regarding admitting for performance ordered operations of atomic transactions across a distributed database. In some embodiments, a node of a distributed system receives and accumulates requests for operations over a period of time. The node can then order the requests based on certain criteria, such as by timestamps of associated transactions. The node can then perform an admission control on the ordered requests, until a capacity of the node to perform the requests for operations is exceeded. During the admission control process, those requests for operations received within the period of time that are not admitted can be rejected by the node.

Abstract: A storage node of a database replica group may distribute different portions of data in local storage and external storage, where local storage and external storage are organized using different types of index structures. Responsive to receiving an access request for a database, a storage node may determine that an item of the database to be accessed by the request does not reside within a first portion of the database stored locally at the storage node. Responsive to this determination, the storage node may obtain from an external storage service a second portion of the database, the second portion including a plurality of items including the item, and the second portion organized according to a structure different from the first portion. The storage node may then store the plurality of obtained items in the first portion and process the request using the first portion of the database.

Abstract: Resilient consistent hashing techniques are implemented to perform requests among nodes of a distributed system. Different load balancers are assigned different groups of request handling nodes that cache data to perform request. Requests are assigned to different load balancers according to a consistent hashing scheme. Load balancers distribute requests among assigned nodes using a load balancing scheme. Different numbers of nodes can be assigned to different load balancers.

Abstract: Techniques for adaptive telemetry using cooperative selective summarization metric reporting are described. Upon an impairment event preventing a client from transmitting raw log data to a server, the client switches to generating summarization data based on the raw log data and sends this summarization data to the server. The server may instruct the client which dimensions of data are to be generated and which time apertures apply for the generation of summary statistics. The client may also switch from a first-in first-out (FIFO) transmission mode to a last-in first-out (LIFO) transmission mode for eventually resending the raw log data, providing the server the most current information as timely as possible while leaving older data for later transmission.

Abstract: A transmission format cache may be implemented at a database storage node. Versions of data items stored in a database at the database storage node may be processed according to anticipated access requests to generate an anticipated access responses. The anticipated access responses are then stored in a transmission format cache to provide low latency reads of the data items. The versions of the data items may be processed as a result of updates to the database items. The database storage node may be one of a plurality of database storage nodes implementing a distributed database system with the transmission format cache implementing a portion of a distributed response cache providing low latency, eventually consistent or consistent reads of data items in a distributed database.

Abstract: A storage node of a database replica group may distribute different portions of data in local storage and external storage, where local storage and external storage are organized using different types of index structures. Responsive to receiving an access request for a database, a storage node may determine that an item of the database to be accessed by the request does not reside within a first portion of the database stored locally at the storage node. Responsive to this determination, the storage node may obtain from an external storage service a second portion of the database, the second portion including a plurality of items including the item, and the second portion organized according to a structure different from the first portion. The storage node may then store the plurality of obtained items in the first portion and process the request using the first portion of the database.

Abstract: Localized lookups for performing access requests to a database may be implemented. Mapping information for storage nodes of a network-based service storing different data for different databases may be obtained by a routing application co-hosted with a client application of the database at a same container host. Access requests from the client application are handled by the routing application and sent to storage nodes identified using the mapping information. An authorization token may be included along with the requests to verify authorization to perform the access request at the storage nodes.

Abstract: A database service that receives and manages time series data into a set of generational data tables. The database service maintains subsets of the time series data in a plurality of partitions and a set of virtual keys defining the range of time series of data in each partition. Thereafter, responsive to a transactional range delete command, the database service identifies partitions having overlapping time series data and processes the delete command at each respective partition.

Abstract: Techniques are described for monitoring and enabling access to information about key access patterns for nonrelational database tables managed by a nonrelational database service of a service provider network. Storage nodes store data as key-value pairs (or key-document pairs), where the records or documents of a database are addressed by a unique key for each record. The storage nodes over time receive requests to perform various operations (for example, to get, put, update, or delete data in a table) associated with records stored by the storage nodes. The storage nodes collect information indicating a frequency with which such requests are received for each key for which a storage node is responsible. This frequency information for each key can be normalized relative to a maximum frequency supported by the storage nodes to obtain an access frequency score, where the maximum frequency indicates a frequency at which additional requests to the storage node may be throttled.

Abstract: Techniques for asynchronously indexing database tables are described herein. An update to data in a database table causes an update to an index table of the database. The update to the index table is made first to the index table and then to a replica of the index table. A first copy of the update is stored in a first replica of the index table and then a second copy of the update is provided to an asynchronous process that stores the second copy of the update in a second replica of the index table.

Abstract: A leader replica of a replica host group of a distributed storage service is configured to replicate the leader replica and its associated one or more secondary replicas to create a duplicate host group comprising a duplicate leader replica and one or more duplicate secondary replicas. The leader replica may appoint the duplicate leader replica or another host as the leader of the duplicate host group. The leader replica may assign a subset of database keys to be served by the duplicate host group and forward data requests directed a key of the subset of keys assigned to the duplicate host group. The leader replica may further update a global key table of the distributed data storage system to direct data requests associated with the subset of database keys to the duplicate leader replica.

Abstract: A leader replica of a replica host group of a distributed storage service is configured to replicate the leader replica and its associated one or more secondary replicas to create a duplicate host group comprising a duplicate leader replica and one or more duplicate secondary replicas. The leader replica may appoint the duplicate leader replica or another host as the leader of the duplicate host group. The leader replica may assign a subset of database keys to be served by the duplicate host group and forward data requests directed a key of the subset of keys assigned to the duplicate host group. The leader replica may further update a global key table of the distributed data storage system to direct data requests associated with the subset of database keys to the duplicate leader replica.

Abstract: A leader replica of a replica host group of a distributed storage service is configured to replicate the leader replica and its associated one or more secondary replicas to create a duplicate host group comprising a duplicate leader replica and one or more duplicate secondary replicas. The leader replica may appoint the duplicate leader replica or another host as the leader of the duplicate host group. The leader replica may assign a subset of database keys to be served by the duplicate host group and forward data requests directed a key of the subset of keys assigned to the duplicate host group. The leader replica may further update a global key table of the distributed data storage system to direct data requests associated with the subset of database keys to the duplicate leader replica.