Abstract: Methods, computer-readable media, and computer systems are provided for initiating storage of data on multiple storage devices and confirming storage of the data after the data has been stored on one but not necessarily all of the devices. A storage server receives, from a client, a request to store data. In response to the request, the storage server initiates, in parallel, storage of the data on multiple storage systems. The storage server detects that the data has been stored on any one of the storage systems, such as an auxiliary system, and, in response, indicates, to the client, that the data has been stored. The storage server may flush or discard data on the auxiliary storage system upon detecting that the data has been successfully stored on a target storage system, where the data persists.

Abstract: Techniques are provided for managing, within a storage system, the sequence in which I/O requests are processed by the storage system based, at least in part, on one or more logical characteristics of the I/O requests. The logical characteristics may include, for example, the identity of the user for whom the I/O request was submitted, the service that submitted the I/O request, the database targeted by the I/O request, an indication of a consumer group to which the I/O request maps, the reason why the I/O request was issued, a priority category of the I/O request, etc. Techniques are also provided for automatically establishing a scheduling policy within a storage system, and for dynamically changing the scheduling policy in response to changes in workload.

Abstract: Techniques are provided for using an intermediate cache between the shared cache of a database server and the non-volatile storage of a storage system. The intermediate cache may be local to the machine upon which the database server is executing, or may be implemented within the storage system. In one embodiment, the database system includes both a DB server-side intermediate cache, and a storage-side intermediate cache. The caching policies used to populate the intermediate cache are intelligent, taking into account factors that may include which database object an item belongs to, the item type of the item, a characteristic of the item; or the database operation in which the item is involved.

Abstract: A method and apparatus for maintaining an item-to-node mapping among nodes in a distributed cluster is provided. Each node maintains locally-stored system-state information indicating that node's understanding of which master nodes are alive and dead. Instead of employing a global item-to-node mapping, each node acts upon a locally determined mapping based on its locally-stored system-state information. For any two nodes with the same locally-stored system-state information, the locally determined mapping is the same. A node updates its locally-stored system-state information upon detecting a node failure or receiving a message from another node indicating different locally-stored system-state information. The new locally-stored system-state information is transmitted on a need-to-know basis, and consequently nodes with different item-to-node mappings may operate concurrently.

Abstract: Techniques are provided for managing, within a storage system, the sequence in which I/O requests are processed by the storage system based, at least in part, on one or more logical characteristics of the I/O requests. The logical characteristics may include, for example, the identity of the user for whom the I/O request was submitted, the service that submitted the I/O request, the database targeted by the I/O request, an indication of a consumer group to which the I/O request maps, the reason why the I/O request was issued, a priority category of the I/O request, etc. Techniques are also provided for automatically establishing a scheduling policy within a storage system, and for dynamically changing the scheduling policy in response to changes in workload.

Abstract: In a consumer-producer distributed model of computing, consumers request data from producers and perform computing work on the data received from the producers, thereby transforming the data. At least some of the computing work performed by a consumer on data provided by the producer is commutable between the consumer and producer, that is, either the producer as well as the consumer can perform the computing work on the data. A producer redistributes commutable based on the work load of the producer and consumer as well as other factors.

Abstract: Techniques are provided for managing, within a storage system, the sequence in which I/O requests are processed by the storage system based, at least in part, on one or more logical characteristics of the I/O requests. The logical characteristics may include, for example, the identity of the user for whom the I/O request was submitted, the service that submitted the I/O request, the database targeted by the I/O request, an indication of a consumer group to which the I/O request maps, the reason why the I/O request was issued, a priority category of the I/O request, etc. Techniques are also provided for automatically establishing a scheduling policy within a storage system, and for dynamically changing the scheduling policy in response to changes in workload.

Abstract: Methods, computer-readable media, and computer systems are provided for initiating storage of data on multiple storage devices and confirming storage of the data after the data has been stored on one but not necessarily all of the devices. A storage server receives, from a client, a request to store data. In response to the request, the storage server initiates, in parallel, storage of the data on multiple storage systems. The storage server detects that the data has been stored on any one of the storage systems, such as an auxiliary system, and, in response, indicates, to the client, that the data has been stored. The storage server may flush or discard data on the auxiliary storage system upon detecting that the data has been successfully stored on a target storage system, where the data persists.

Abstract: Techniques are provided for managing, within a storage system, the sequence in which I/O requests are processed by the storage system based, at least in part, on one or more logical characteristics of the I/O requests. The logical characteristics may include, for example, the identity of the user for whom the I/O request was submitted, the service that submitted the I/O request, the database targeted by the I/O request, an indication of a consumer group to which the I/O request maps, the reason why the I/O request was issued, a priority category of the I/O request, etc. Techniques are also provided for automatically establishing a scheduling policy within a storage system, and for dynamically changing the scheduling policy in response to changes in workload.

Abstract: Techniques are provided for managing, within a storage system, the sequence in which I/O requests are processed by the storage system based, at least in part, on a one or more logical characteristics of the I/O requests. The logical characteristics may include, for example, the identity of the user for whom the I/O request was submitted, the service that submitted the I/O request, the database targeted by the I/O request, an indication of a consumer group to which the I/O request maps, the reason why the I/O request was issued, a priority category of the I/O request, etc. Techniques are also provided for automatically establishing a scheduling policy within a storage system, and for dynamically changing the scheduling policy in response to changes in workload.

Abstract: Techniques are provided for using an intermediate cache between the shared cache of a database server and the non-volatile storage of a storage system. The intermediate cache may be local to the machine upon which the database server is executing, or may be implemented within the storage system. In one embodiment, the database system includes both a DB server-side intermediate cache, and a storage-side intermediate cache. The caching policies used to populate the intermediate cache are intelligent, taking into account factors that may include which database object an item belongs to, the item type of the item, a characteristic of the item; or the database operation in which the item is involved.

Abstract: Techniques are provided for using an intermediate cache to provide some of the items involved in a scan operation, while other items involved in the scan operation are provided from primary storage. Techniques are also provided for determining whether to service an I/O request for an item with a copy of the item that resides in the intermediate cache based on factors such as a) an identity of the user for whom the I/O request was submitted, b) an identity of a service that submitted the I/O request, c) an indication of a consumer group to which the I/O request maps, d) whether the I/O request is associated with an offloaded filter provided by the database server to the storage system, or e) whether the intermediate cache is overloaded. Techniques are also provided for determining whether to store items in an intermediate cache in response to the items being retrieved, based on logical characteristics associated with the requests that retrieve the items.

Abstract: Techniques are provided for managing, within a storage system, the sequence in which I/O requests are processed by the storage system based, at least in part, on a one or more logical characteristics of the I/O requests. The logical characteristics may include, for example, the identity of the user for whom the I/O request was submitted, the service that submitted the I/O request, the database targeted by the I/O request, an indication of a consumer group to which the I/O request maps, the reason why the I/O request was issued, a priority category of the I/O request, etc. Techniques are also provided for automatically establishing a scheduling policy within a storage system, and for dynamically changing the scheduling policy in response to changes in workload.

Abstract: A method and apparatus for maintaining an item-to-node mapping among nodes in a distributed cluster is provided. Each node maintains locally-stored system-state information indicating that node's understanding of which master nodes are alive and dead. Instead of employing a global item-to-node mapping, each node acts upon a locally determined mapping based on its locally-stored system-state information. For any two nodes with the same locally-stored system-state information, the locally determined mapping is the same. A node updates its locally-stored system-state information upon detecting a node failure or receiving a message from another node indicating different locally-stored system-state information. The new locally-stored system-state information is transmitted on a need-to-know basis, and consequently nodes with different item-to-node mappings may operate concurrently.

Abstract: A method and apparatus for the dynamic management of disk space by multiple database server instances in a cluster configuration is disclosed. A segment is partitioned. Each partition is associated with a bitmap block. A partition's bitmap block indicates the freeness of the partition's data blocks. A partition's bitmap block may be owned by one server instance at a time. After determining from a partition's bitmap block where free disk space is located within the partition, the partition's bitmap block's owner may allocate the free disk space for the owner's use. A bitmap block may become owned by different server instances at different times. When a server instance ceases to actively use its bitmap block, another server instance may “steal” the bitmap block. Thus, multiple server instances may allocate disk space in the same partition over time, preventing disk space waste.

Abstract: A method and apparatus for the dynamic management of disk space by multiple database server instances in a cluster configuration is disclosed. A segment is partitioned. Each partition is associated with a bitmap block. A partition's bitmap block indicates the freeness of the partition's data blocks. A partition's bitmap block may be owned by one server instance at a time. After determining from a partition's bitmap block where free disk space is located within the partition, the partition's bitmap block's owner may allocate the free disk space for the owner's use. A bitmap block may become owned by different server instances at different times. When a server instance ceases to actively use its bitmap block, another server instance may “steal” the bitmap block. Thus, multiple server instances may allocate disk space in the same partition over time, preventing disk space waste.