Techniques for recovering from session failures between clients and database servers are described herein. A session may be established between a client and a first database server to handle a database query for the client. A command of the session may be received by the first database server from the client. Data requested by the command may be retrieved. Prior to responding to the command, the data is spooled to a session state stored in a repository of the first database server, and the session state is replicated to one or more additional database servers. The session state stored in the repository of the first database server enables the first database server and client to recover from a failure of the session. The replicated session state enables the additional database server(s) to reestablish the session and respond to the command, instead of the first database server, if the session fails.

As disclosed herein a computer system for secure database backup and recovery in a secure database network has N distributed data nodes. The computer system includes program instructions that include instructions to receive a database backup file, fragment the file using a fragment engine, and associate each fragment with one node, where the fragment is not stored on the associated node. The program instructions further include instructions to encrypt each fragment using a first encryption key, and store, randomly, encrypted fragments on the distributed data nodes. The program instructions further include instructions to retrieve the encrypted fragments, decrypt the encrypted fragments using the first encryption key, re-encrypt the decrypted fragments using a different encryption key, and store, randomly, the re-encrypted fragments on the distributed data nodes. A computer program product and method corresponding to the above computer system are also disclosed herein.

Example implementations disclosed herein can be used to build, maintain, and use a hash table distributed across the plurality multiple nodes in a multi-node computing system. The hash table can include data pages associated by corresponding pointers according to a tree data structure. The data pages include leaf data pages. Each leaf data page can be associated with a corresponding hash value and include a tag bitmap. When a transaction associated with a key is executed, a hash value and a tag value are generated based on the key. The leaf data pages can be searched using the hash value. A probability that a leaf data page includes the key can be determined based on a comparison tag value with the tag bitmap.

Systems and methods for managing a highly available distributed hybrid database comprising: a memory storing instructions; and one or more processors configured to execute the instructions to: receive a query from a user device to retrieve data from a distributed database comprising a source node, a first plurality of replica nodes, and a second plurality of replica nodes, wherein the source node and the first plurality of replica nodes form a transactional cluster, and wherein the second plurality of replica nodes forms an analytical cluster; determine whether to process the query using the transactional cluster or the analytical cluster based on one or more rules; translate the query into a first protocol that the determined cluster comprehends; select a replica node corresponding to the determined cluster; process the query using the selected replica node; and send data associated with results from processing the query to the user device.

Described in detail herein are systems and methods for single instancing blocks of data in a data storage system. For example, the data storage system may include multiple computing devices (e.g., client computing devices) that store primary data. The data storage system may also include a secondary storage computing device, a single instance database, and one or more storage devices that store copies of the primary data (e.g., secondary copies, tertiary copies, etc.). The secondary storage computing device receives blocks of data from the computing devices and accesses the single instance database to determine whether the blocks of data are unique (meaning that no instances of the blocks of data are stored on the storage devices). If a block of data is unique, the single instance database stores it on a storage device. If not, the secondary storage computing device can avoid storing the block of data on the storage devices.

A distributed database system, a data disaster backup exercise method and a non-transitory computer-readable storage medium are disclosed. The distributed database system may include a local computer room (110) and an offsite computer room (120), where the local computer room (110) includes a local management node (111) and a local database cluster (112), the offsite computer room (120) includes an offsite management node (121), an offsite exercise database cluster (123) and an offsite synchronization database cluster (122); where the local database cluster (112) and the offsite synchronization database cluster (122) are both connected with the local management node (111); the offsite exercise database cluster (123) is configured for: establishing a first connection with the offsite management node (121); and receiving a test service sent by a service layer.

Techniques described herein relate to systems and methods of data storage, and more particularly to providing layering of file system functionality on an object interface. In certain embodiments, file system functionality may be layered on cloud object interfaces to provide cloud-based storage while allowing for functionality expected from a legacy applications. For instance, POSIX interfaces and semantics may be layered on cloud-based storage, while providing access to data in a manner consistent with file-based access with data organization in name hierarchies. Various embodiments also may provide for memory mapping of data so that memory map changes are reflected in persistent storage while ensuring consistency between memory map changes and writes. For example, by transforming a ZFS file system disk-based storage into ZFS cloud-based storage, the ZFS file system gains the elastic nature of cloud storage.

Systems and methods for managing incremental data backups on an object store. A computing device receives first data representing a changed chunk of data in a revision of a data volume on a storage device, the changed chunk includes data having changes from previous data of a previous revision. The computing device creates a block of data representing a copy of the changed chunk on the object store, the object store also includes a previous revision block representing previous revision data. The computing device determines a previous index stored on the object store corresponding to the previous revision, which includes entries including at least one corresponding to the previous revision block. The computing device creates a copy of at least one previous index from the object store, and a revised index that updates the corresponding entry with updated entry data representing the change block.

An example networked computing system for iterative node level recovery comprises a node cluster; a database; at least one processor configured by instructions to perform operations comprising at least: identifying a failed node among existing nodes in the node cluster; identifying and initiating a replacement node as a new node for the node cluster; accessing at the database a logical backup of the node cluster; retrieving logical backup data of the node cluster and identifying specific rows of backup data to be restored to the new node; restoring the specific data rows to the new node; identifying new data written by applications, to the existing nodes of the node cluster, during restoration of the new node; iteratively accessing supplementary back up data to identify supplementary data rows to be restored to the new node; and iteratively restoring the supplementary data rows to the new node until the new node is synchronized with the existing nodes in the node cluster.

A distributed database encrypts tables using table encryption keys protected by a client master encryption key. The client may revoke authorization to access the client master encryption key. Subsequent to a revocation of authority to access the client master encryption key, the distributed database generates interim snapshots of the table using the table encryption key. Also subsequent to the revocation, the distributed database generates a backup of the table using a backup encryption key protected by the client master encryption key.