Abstract: A storage device uses non-volatile memory devices for caching. The storage device operates in a mode referred to herein as write-back mode. In write-back mode, a storage device responds to a request to write data by persistently writing the data to a cache in a non-volatile memory device and acknowledges to the requestor that the data is written persistently in the storage device. The acknowledgement is sent without necessarily having written the data that was requested to be written to primary storage. Instead, the data is written to primary storage later.

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 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, or d) 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: A partial reverse key index is described, which allows distributed contention as resources vie to insert data into an index as well as allows range scans to be performed on the index. To do so, before an index entry for a key value is inserted into an index, the key value is transformed using a transformation operation that affects a subset of the order of the key value. The index entry is then inserted based on the transformed key value. Because the transformation operation affects the order of the key value, the transformed values associated with two consecutive key values will not necessarily be consecutive. Therefore, the index entries associated with the consecutive key values may be inserted into unrelated portions of the index.

Abstract: A storage device uses non-volatile memory devices for caching. The storage device operates in a mode referred to herein as write-back mode. In write-back mode, a storage device responds to a request to write data by persistently writing the data to a cache in a non-volatile memory device and acknowledges to the requestor that the data is written persistently in the storage device. The acknowledgement is sent without necessarily having written the data that was requested to be written to primary storage. Instead, the data is written to primary storage later.

Abstract: A method and apparatus for auto-tuning memory is provided. Memory on a computer system comprises at least one shared memory area and at least one private memory area. Addresses in the shared memory area are accessible to multiple processes. Addresses in the private memory area are dedicated to individual processes. Initially, a division in the amount of memory is established between the shared and private memory areas. Subsequently, a new division is determined. Consequently, memory from one memory area is “given” to the other memory area. In one approach, such sharing is achieved by causing the shared and private memory areas to be physically separate from each other both before and after a change in the division. The division of the amount of memory may be changed to a new division by deallocating memory from one of the memory areas and allocating that memory to the other of the memory areas.

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: A partial reverse key index is described, which allows distributed contention as resources vie to insert data into an index as well as allows range scans to be performed on the index. To do so, before an index entry for a key value is inserted into an index, the key value is transformed using a transformation operation that affects a subset of the order of the key value. The index entry is then inserted based on the transformed key value. Because the transformation operation affects the order of the key value, the transformed values associated with two consecutive key values will not necessarily be consecutive. Therefore, the index entries associated with the consecutive key values may be inserted into unrelated portions of the index.

Abstract: A method and apparatus for auto-tuning memory is provided. Memory on a computer system comprises at least one shared memory area and at least one private memory area. Addresses in the shared memory area are accessible to multiple processes. Addresses in the private memory area are dedicated to individual processes. Initially, a division in the amount of memory is established between the shared and private memory areas. Subsequently, a new division is determined. Consequently, memory from one memory area is “given” to the other memory area. In one approach, such sharing is achieved by causing the shared and private memory areas to be physically separate from each other both before and after a change in the division. The division of the amount of memory may be changed to a new division by deallocating memory from one of the memory areas and allocating that memory to the other of the memory areas.