Abstract: Methods and apparatus for conditional master election in a distributed database are described. A plurality of replicas of a database object are stored by a distributed database service. Some types of operations corresponding to client requests directed at the database object are to be coordinated by a master replica. Client access to the database object is enabled prior to election of a master replica. In response to a triggering condition, a particular replica is elected master. The master coordinates implementation of operations with one or more other replicas in response to client requests.

Abstract: Methods and apparatus for conditional master election in a distributed database are described. A plurality of replicas of a database object are stored by a distributed database service. Some types of operations corresponding to client requests directed at the database object are to be coordinated by a master replica. Client access to the database object is enabled prior to election of a master replica. In response to a triggering condition, a particular replica is elected master. The master coordinates implementation of operations with one or more other replicas in response to client requests.

Abstract: Methods and apparatus for token-based admission control for replicated writes are disclosed. Data objects are divided into partitions, and corresponding to each partition, at least a master replica and a slave replica are stored. A determination as to whether to accept a write request directed to the partition is made based at least in part on one or more of (a) available throughput capacity at the master replica, and (b) an indication, obtained using a token-based protocol, of available throughput capacity at the slave replica. If the write request is accepted, one or more data modification operations are initiated.

Abstract: Distributed database management systems may perform range queries over the leading portion of a primary key. Non-random distribution of data may improve performance related to the processing of range queries, but may tend to cause workload to be concentrated on particular partitions. Groups of partitions may be expanded and collapsed based on detection of disproportionate workload. Disproportionate write workload may be distributed among a group of partitions that can subsequently be queried using a federated approach. Disproportionate read workload may be distributed among a group of read-only replicated partitions.

Abstract: A pricing policy to be applied to token population changes at a token bucket used for admission control during burst-mode operations at a work target is determined. Over a time period, changes to the token population of that bucket are recorded. An amount to be charged to a client is determined, based on the recorded changes in token population and an associated pricing amount indicated in the policy.

Abstract: A distributed database management system may comprise a plurality of computing nodes. A request to update an item maintained by the system may be acknowledged as durable and committed once an entry corresponding to the request has been written to a log file and quorum among the computing nodes has been achieved. Improved consistency may be achieved by maintaining snapshots of committed item states within queryable in-memory snapshot data structures. Range queries may be performed by merging a secondary index with the snapshots and applying filters. Projections may be completed by retrieving additional data from an item collection maintain on one or more storage devices.

Abstract: Methods and apparatus for conditional master election in a distributed database are described. A plurality of replicas of a database object are stored by a distributed database service. Some types of operations corresponding to client requests directed at the database object are to be coordinated by a master replica. Client access to the database object is enabled prior to election of a master replica. In response to a triggering condition, a particular replica is elected master. The master coordinates implementation of operations with one or more other replicas in response to client requests.

Abstract: Methods and apparatus for conditional master election in a distributed database are described. A plurality of replicas of a database object are stored by a distributed database service. Some types of operations corresponding to client requests directed at the database object are to be coordinated by a master replica. Client access to the database object is enabled prior to election of a master replica. In response to a triggering condition, a particular replica is elected master. The master coordinates implementation of operations with one or more other replicas in response to client requests.

Abstract: Methods and apparatus for configurable-capacity time-series tables are disclosed. A schedule of database table management operations, including at least an operation to change a throughput constraint associated with a table in response to a triggering event, is generated. The table is instantiated with an initial throughput constraint in accordance with the schedule. Work requests directed to the table are accepted based on the initial throughput constraint. The throughput constraint is modified in response to the triggering event. Subsequent work requests are accepted based on the modified throughput constraint.

Abstract: Partitions of a hosted computing service may be maintained on a computing node. Processing of requests to access the partition may be limited to constrain capacity utilization to a provisioned amount of capacity reserved for the partition. A second, additional amount of capacity may be associated with the partition and may reflect potential future changes to the provisioned amount of capacity. A sum of provisioned and additional capacities associated with partitions on a computing node may be calculated. The computing node may be ranked, relative to other computing nodes, for maintaining new or relocated partitions based on the sum.

Abstract: A data storage system may implement recommending throughput capacity for generating a secondary index for an online table. Secondary indexes may be created for a table stored in multiple partitions in the data storage system. The data storage system may allow users to provision throughput capacity to process access requests at secondary indexes. The throughput capacity may also be used to perform updates at the secondary index as part of generating the secondary index. A creation throughput capacity may be determined that compensates for performing the updates to generate the secondary index. A user may receive a recommendation with the creation throughput capacity for creating the secondary index and may accept or modify the creation throughput capacity. The creation throughput may be automatically provisioned to create the secondary index, in some embodiments.

Abstract: A distributed database management system may comprise a plurality of computing nodes. A request to update an item maintained by the system may be acknowledged as durable and committed once an entry corresponding to the request has been written to a log file and quorum among the computing nodes has been achieved. Improved consistency may be achieved by maintaining snapshots of committed item states within queryable in-memory snapshot data structures. Range queries may be performed by merging a secondary index with the snapshots and applying filters. Projections may be completed by retrieving additional data from an item collection maintain on one or more storage devices.

Abstract: A hosted service may limit access to a table initially comprising one or more partitions. Access to the table may be limited to a provisioned capacity. A client of the service may request an increased capacity. A minimum number of partitions for providing the increased capacity may be determined. Proportions of the increased capacity may be allocated among members of successive generations of partitions to be provided by a member of a generation or its descendants. The proportions may be allocated to minimize the costs associated with splitting partitions based on the minimum number of partitions.

Abstract: A distributed database management system may comprise a plurality of computing nodes. A request to update an item maintained by the system may be acknowledged as durable and committed once an entry corresponding to the request has been written to a log file and quorum among the computing nodes has been achieved. Improved consistency may be achieved by maintaining snapshots of committed item states within queryable in-memory snapshot data structures. Range queries may be performed by merging a secondary index with the snapshots and applying filters. Projections may be completed by retrieving additional data from an item collection maintain on one or more storage devices.

Abstract: Methods and apparatus for equitable distribution of excess shared-resource throughput capacity are disclosed. A first and a second work target are configured to access a shared resource to implement accepted work requests. Admission control is managed at the work targets using respective token buckets. A first metric indicative of the work request arrival rates at the work targets during a time interval, and a second metric associated with the provisioned capacities of the work targets are determined. A number of tokens determined based on a throughput limit of the shared resource is distributed among the work targets to be used for admission control during a subsequent time interval. The number of tokens distributed to each work target is based on the first metric and/or the second metric.

Abstract: Methods and apparatus for conditional master election in a distributed database are described. A plurality of replicas of a database object are stored by a distributed database service. Some types of operations corresponding to client requests directed at the database object are to be coordinated by a master replica. Client access to the database object is enabled prior to election of a master replica. In response to a triggering condition, a particular replica is elected master. The master coordinates implementation of operations with one or more other replicas in response to client requests.

Abstract: Methods and apparatus for equitable distribution of excess shared-resource throughput capacity are disclosed. A first and a second work target are configured to access a shared resource to implement accepted work requests. Admission control is managed at the work targets using respective token buckets. A first metric indicative of the work request arrival rates at the work targets during a time interval, and a second metric associated with the provisioned capacities of the work targets are determined. A number of tokens determined based on a throughput limit of the shared resource is distributed among the work targets to be used for admission control during a subsequent time interval. The number of tokens distributed to each work target is based on the first metric and/or the second metric.

Abstract: Partitions of a hosted computing service may be maintained on a computing node. Processing of requests to access the partition may be limited to constrain capacity utilization to a provisioned amount of capacity reserved for the partition. A second, additional amount of capacity may be associated with the partition and may reflect potential future changes to the provisioned amount of capacity. A sum of provisioned and additional capacities associated with partitions on a computing node may be calculated. The computing node may be ranked, relative to other computing nodes, for maintaining new or relocated partitions based on the sum.

Abstract: A distributed database management system may comprise a plurality of computing nodes. A request to update an item maintained by the system may be acknowledged as durable and committed once an entry corresponding to the request has been written to a log file and quorum among the computing nodes has been achieved. Improved consistency may be achieved by maintaining snapshots of committed item states within queryable in-memory snapshot data structures. Range queries may be performed by merging a secondary index with the snapshots and applying filters. Projections may be completed by retrieving additional data from an item collection maintain on one or more storage devices.

Abstract: Methods and apparatus for conditional master election in a distributed database are described. A plurality of replicas of a database object are stored by a distributed database service. Some types of operations corresponding to client requests directed at the database object are to be coordinated by a master replica. Client access to the database object is enabled prior to election of a master replica. In response to a triggering condition, a particular replica is elected master. The master coordinates implementation of operations with one or more other replicas in response to client requests.