Abstract: A method for handling storage in a virtualization environment including identifying a situation in which a storage controller ownership change is to occur for a virtual disk, identifying a candidate replacement owner for the virtual disk and transferring ownership of the virtual disk to the candidate replacement owner.

Abstract: A system for communicating to a storage controller in a virtualization environment, including a plurality of nodes, wherein the plurality of nodes implements a virtualization environment, and a node comprises a hypervisor and multiple user virtual machines; a plurality of storage devices that are accessed by the virtual machine; and a storage controller implemented as a service virtual machine on the node to manage access by the multiple user virtual machines to the plurality of storage devices, wherein a networking protocol is used to communicate between the multiple user virtual machines and the storage controller.

Abstract: A system for implementing a virtual disk in a virtualization environment, including a plurality of nodes, wherein the plurality of nodes implements a virtualization environment, and a node comprises a hypervisor, user virtual machines, and a storage controller implemented as a service virtual machine; a plurality of storage devices that are accessed by user virtual machines and are managed by storage controllers, in which a first and a second virtual disk (vDisk) are formed from the plurality of storage devices and the first virtual disk is accessible by just a first user virtual machine and the second virtual disk is accessible by just a second user virtual machine.

Abstract: A computer is programmed to compress data of a database in response to database modification language (DML) statements generated by on-line transaction processing (OLTP) systems. In several embodiments, data that is initially added to a database block is left uncompressed until a predetermined condition is satisfied, which happens infrequently (relative to OLTP transactions on the block). When satisfied, the computer automatically compresses all uncompressed data in the block, which increases the amount of unused space in the block. New data is thereafter added uncompressed to the partially compressed block, until satisfaction of a predetermined condition whereby the partially compressed block is again compressed, i.e. re-compressed. Adding of new data to a partially compressed block and its compression are repeated unless another predetermined condition is met, in response to which the block is not further re-compressed, thereby to recognize a limit on the benefit from compression.

Abstract: A method, system and computer program product are described for state maintenance of a large object. In one approach, the method, system and computer program product perform by associating one or more buffers with a transaction involving a large object, the large object data may be accessed using the one or more buffers during the transaction, and storing data for the large object from the one or more buffers in one or more sets of contiguous blocks. In one approach, a system performs state maintenance of a large object with a cache that associates one or more buffers with a transaction involving a large object, the large object data may be accessed using the one or more buffers during the transaction, and the cache stores large object data from the one or more buffers in one or more sets of contiguous blocks in storage.

Abstract: A method of processing data from a file includes obtaining a first portion of the file, creating a first compression unit by compressing at least the first portion of the file, obtaining a second portion of the file, creating a second compression unit by compressing at least the second portion of the file, and storing the first and second compression unit such that each of the first and the second compression units can be individually accessed. A method of processing data from a file includes receiving a request to access a portion of the file, determining one or more sub-units that include compressed data associated with the portion of the file, de-compressing the compressed data in the one or more sub-units to obtain de-compressed data, and transmitting the de-compressed data in response to the request.

Abstract: Disclosed is an improved approach to implement I/O and storage device management in a virtualization environment. According to some approaches, a Service VM is employed to control and manage any type of storage device, including directly attached storage in addition to networked and cloud storage. The Service VM implements the Storage Controller logic in the user space, and can be migrated as needed from one node to another. IP-based requests are used to send I/O request to the Service VMs. The Service VM can directly implement storage and I/O optimizations within the direct data access path, without the need for add-on products.

Abstract: A computer is programmed to compress data of a database in response to database modification language (DML) statements generated by on-line transaction processing (OLTP) systems. In several embodiments, data that is initially added to a database block is left uncompressed until a predetermined condition is satisfied, which happens infrequently (relative to OLTP transactions on the block). When satisfied, the computer automatically compresses all uncompressed data in the block, which increases the amount of unused space in the block. New data is thereafter added uncompressed to the partially compressed block, until satisfaction of a predetermined condition whereby the partially compressed block is again compressed, i.e. re-compressed. Adding of new data to a partially compressed block and its compression are repeated unless another predetermined condition is met, in response to which the block is not further re-compressed, thereby to recognize a limit on the benefit from compression.

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 computer is programmed to compress data of a database in response to database modification language (DML) statements generated by on-line transaction processing (OLTP) systems. In several embodiments, data that is initially added to a database block is left uncompressed until a predetermined condition is satisfied, which happens infrequently (relative to OLTP transactions on the block). When satisfied, the computer automatically compresses all uncompressed data in the block, which increases the amount of unused space in the block. New data is thereafter added uncompressed to the partially compressed block, until satisfaction of a predetermined condition whereby the partially compressed block is again compressed, i.e. re-compressed. Adding of new data to a partially compressed block and its compression are repeated unless another predetermined condition is met, in response to which the block is not further re-compressed, thereby to recognize a limit on the benefit from compression.

Abstract: Techniques are provided for processing a CREATE INDEX statement that avoids one or more locks on the underlying table. The processing of such a statement may be divided into a build phase and a cooperation phase. During the build phase, a journal table is created and published. A snapshot of the table is obtained after the last DML transaction (that was pending at the time the journal table was published) commits. The index is built based on the state of the table as of the snapshot. Any changes to the table while the index is built are recorded in the journal table. During the cooperation phase, the index is partially published. A subsequent DML statement determines whether any changes in the journal table affect the same data as the subsequent DML statement. If so, then those changes are applied to the index followed by the subsequent DML statement.

Abstract: A method of processing data from a file includes obtaining a first portion of the file, encrypting the first portion of the file to create a first encrypted portion, obtaining a second portion of the file, encrypting the second portion of the file to create a second encrypted portion, and storing the first and second encrypted portions such that each of the first and the second encrypted portions can be individually accessed. A method of processing data from a file includes receiving a request to access a first portion of the file, wherein data in the first portion of the file is encrypted, and data in a second portion of the file is encrypted, and decrypting the data in the first portion, and not the data in the second portion.

Abstract: Methods and systems for automatically tuning the undo retention in a database system are disclosed. The undo tablespace may be of a fixed size or may be set to be automatically extended. If the undo tablespace is of a fixed size, the undo retention is set to a “best possible” undo retention, which is calculated based on statistical data stored in the system. If the undo tablespace is configured to be automatically extensible, the undo retention may be set to be greater than the duration of the longest running query in the system. The duration of the longest running query may be calculated in a distributed process in which each instance broadcasts information about its longest running query to other instances.

Abstract: Disclosed is a system and method for implementing space management for large objects stored in the computing system. According to some approaches, storage of large objects are managed by dynamically creating contiguous chunks of storage space of varying lengths. The length of each chunk may vary depending upon object size being stored, fragmentation of the storage space, available free space, and/or expected length of the object.

Abstract: Performing an operation directly on data stored in a database table provides for avoiding generation and processing of SQL statements. A Data Layer interface, comprising a set of APIs, allows internal database server components to call directly to the Data Layer for making fast row changes to a table. According to an embodiment, before making any row change to a table through this Data Layer interface, a shared state data structure is created to hold the metadata about the table. A single shared state can be used for all DML changes to a particular table regardless of what columns are updated or inserted during each DML operation. When a process needs to change a row, the process uses a mutable state based on the shared state of the table.

Abstract: A computer modifies data inside a database large object (LOB) of unknown structure without modifying other data in the remainder of the LOB. Insertion of new data at a specified location in the LOB does not require movement of existing data in the LOB. Instead, the computer is programmed to insert new data at a physical end of the LOB, and modify metadata based on the specified location. Similarly, deletion of existing data from a specified location in the LOB is performed without movement of other data in the LOB, by updating the metadata. The computer uses the metadata when reading from the LOB, so that the new data is automatically read whenever the specified location is accessed. The computer may optionally output a handle that is static, relative to other insertions and deletions, to identify specific data within the LOB, for use in building indexes on the LOB.

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 computer is programmed to compress data of a database in response to database modification language (DML) statements generated by on-line transaction processing (OLTP) systems. In several embodiments, data that is initially added to a database block is left uncompressed until a predetermined condition is satisfied, which happens infrequently (relative to OLTP transactions on the block). When satisfied, the computer automatically compresses all uncompressed data in the block, which increases the amount of unused space in the block. New data is thereafter added uncompressed to the partially compressed block, until satisfaction of a predetermined condition whereby the partially compressed block is again compressed, i.e. re-compressed. Adding of new data to a partially compressed block and its compression are repeated unless another predetermined condition is met, in response to which the block is not further re-compressed, thereby to recognize a limit on the benefit from compression.

Abstract: Disclosed is a system and method for implementing space management for large objects stored in the computing system. According to some approaches, storage of large objects are managed by dynamically creating contiguous chunks of storage space of varying lengths. The length of each chunk may vary depending upon object size being stored, fragmentation of the storage space, available free space, and/or expected length of the object.

Abstract: A method, system and computer program product are described for state maintenance of a large object. In one approach, the method, system and computer program product perform by associating one or more buffers with a transaction involving a large object, the large object data may be accessed using the one or more buffers during the transaction, and storing data for the large object from the one or more buffers in one or more sets of contiguous blocks. In one approach, a system performs state maintenance of a large object with a cache that associates one or more buffers with a transaction involving a large object, the large object data may be accessed using the one or more buffers during the transaction, and the cache stores large object data from the one or more buffers in one or more sets of contiguous blocks in storage.