Described are methods, systems and computer readable media for providing a current row position query language construct and array processing query language constructs and associated processing.

Disclosed herein are system, method, and computer-readable device embodiments for mass insertion into single-threaded databases. An embodiment includes a processor and a memory, a storage layer to interface with a plurality of software applications and to receive data output from the plurality of software applications, and a listener that runs according to an update policy, to detect the presence of information newly stored within the storage layer. The processor and memory may be configured to maintain at least a part of a running database cluster including a plurality of nodes, with at least two nodes configured to run without multi-threading, and to execute an intermediate module to send at least part of the information to the database cluster, and to perform simultaneous access to multiple database nodes running without multi-threading.

In an example embodiment, a solution is used to provide container volume replication via a container storage replication log and volume buffer synchronization, which is built on top of a container cloud platform whose container metadata and replication runtime configuration are all managed by a storage manager (a service orchestrated by its job scheduler and service orchestrator). This container volume replication ensures the data security for a long-running service in the container. In the case of any disaster, the in-memory database and application data inside of the container can be recovered via volume replication. This provides container volume replication for long-running containerized applications whose states keep changing.

In an example embodiment, a solution is used to provide container volume replication via a container storage replication log and volume buffer synchronization, which is built on top of a container cloud platform whose container metadata and replication runtime configuration are all managed by a storage manager (a service orchestrated by its job scheduler and service orchestrator). This container volume replication ensures the data security for a long-running service in the container. In the case of any disaster, the in-memory database and application data inside of the container can be recovered via volume replication. This provides container volume replication for long-running containerized applications whose states keep changing.

Techniques of transaction support for a database are disclosed herein. One example technique includes generating a new version value for key-value pairs in the database and creating, in the database, a new key-value pair corresponding to a parameter to be updated with a new value using both the generated new version value and a name of the parameter as a key and the new value as the corresponding value for the created new key-value pair. The example technique can then include determining whether creating the new key-value pair is completed successfully in the database, and in response to determining that creating the new key-value pair corresponding to the parameter is not completed successfully, the existing value of the parameter is returned as a current value of the parameter instead of the new value in response to a query for the current value of the parameter.

Techniques are disclosed relating to efficiently managing skip list data structures. In some embodiments, a computing system stores a skip list including a plurality of key-value records that include one or more pointers to others of the plurality of key-value records. The computing system scans the plurality of key-value records in key order to identify key-value records to be purged from the skip list. The scanning includes maintaining a list of key-value records that include pointers that point to key-value records that have not yet been scanned by the scanning. In response to identifying a key-value record for purging, the computing system purges the key-value record by substituting the pointers included the key-value records of the list with pointers included in the key-value record being purged.

A method of rescinding access to blockchain data may include the addition of metadata to an entire blockchain or to component blocks in a blockchain which contain the encrypted keys for each owner or otherwise authorized party. Said metadata may be added when a block is created, including metadata to store state and communicate information. After a blockchain is published, an authorized party may request rescission of access to one or more blocks or the entire blockchain by appending one or more instruction blocks to the chain. The other parties authorized to access this block or blockchain may agree to said request. If a sufficient number of parties have agreed to rescind, the removal of access keys may be publicly confirmed with the result that the original data held within the block or blockchain can no longer be decrypted.

A method for operating a database and a cache of at least a portion of the database may include receiving a plurality of read requests to read a data entity from the database and counting respective quantities of the requests serviced from the database and from the cache. The method may further include receiving a write request to alter the data entity in the database and determining whether to update the cache to reflect the alteration to the data entity in the write request according to the quantity of the requests serviced from the database and the quantity of the requests serviced from the cache. In an embodiment, the method further includes causing the cache to be updated when a ratio of the quantity of the requests serviced from the database to the quantity of the requests serviced from the cache exceeds a predetermined threshold.

A database system is provided, including a first global transaction manager (GTM), a first data node) DN, and a coordinator node (CN). The CN is configured to send a query to the first DN. The first DN is configured to, in response to the query, determine a target commit sequence number (CSN), determine a committed transaction on the first DN based on the target CSN, and determine a query result corresponding to the query based on the committed transaction. The target CSN is allocated by the first GTM. The target CSN is used to distinguish between the committed transaction and an active transaction on the first DN. The active transaction is a transaction that is being executed. In addition, a corresponding transaction management method is provided. The CSN is used to replace an active transaction linked list. This reduces network traffic and improves concurrency and scalability of the database system.

A system is provided for creating selective snapshots of a database that is stored as one or more segments, wherein a segment comprises one or more memory pages. The system includes a memory storage comprising instructions and one or more processors in communication with the memory. The one or more processors execute the instructions to determine whether a snapshot process is configured to access a selected segment of the one or more segments, assign a positive mapping status to an accessed segment for which the determining unit has determined that it is accessed by the snapshot process and to assign a negative mapping status to a non-accessed segment, and create a snapshot comprises a step of forking the snapshot process with an address space that comprises a subset of the one or more segments.