Abstract: A system and method for managing cache eviction are provided. The method includes establishing a plurality of time cycles for a cache, each time cycle including at least one tick, wherein an occurrence of a tick is variably determined; assigning a heat score to each cached data item of a plurality of cached data items; maintaining each cached data item in a partition of a plurality of contiguous partitions based on a heat score range of each partition that the heat score of each cached data item is within; when a cached data item is accessed, updating a first heat score of the cached data item to a second heat score; and when inserting at least one data item into the cache exceeds storage space of the cache, evicting at least one cached data item from an eviction-ready partition.

Abstract: A system and method for maintaining a persistent key-value store is presented. The method includes mirroring at least one persistent page to at least one corresponding non-persistent page, wherein the at least one persistent page and the at least one corresponding non-persistent page each contain at least one slot each containing a key-value pair entry and an associated update number (UN); maintaining an association of a key with a pointer, wherein the pointer points to the slot containing the key-value pair entry, for the key, with the highest UN; and maintaining an association of a key with a reference counter (REFC), wherein the REFC counts the number of key-value pair entries, for the key, whose UN is below a maximum; maintaining, for each slot, a marking at least of used or available; and performing key-value store operations on the non-persistent page before they are persisted to the persistent page.

Abstract: A system and method for managing cache eviction are provided. The method includes establishing a plurality of time cycles for a cache, each time cycle including at least one tick, wherein an occurrence of a tick is variably determined; assigning a heat score to each cached data item of a plurality of cached data items; maintaining each cached data item in a partition of a plurality of contiguous partitions based on a heat score range of each partition that the heat score of each cached data item is within; when a cached data item is accessed, updating a first heat score of the cached data item to a second heat score; and when inserting at least one data item into the cache exceeds storage space of the cache, evicting at least one cached data item from an eviction-ready partition.

Abstract: A system and method for a remote procedure call are provided. The method includes brokering client-server communications, wherein client-server communications include a client’s request message for an operation, a server’s response message with the results of the operation, and a purge message acknowledging receipt of the results; establishing, through system messages, time-frames for client-server communications, wherein time-frames are established to enable detection of client-server communications that have not been timely received; tagging the client-server communications with time-frame numbers corresponding to the time-frames in which each client-server communication is sent; detecting that at least one client-server communication, sent in one time-frame, is not received in a pre-determined number of subsequent time-frames; and retransmitting the at least one client-server communication.

Abstract: A method for cleaning unneeded row-versions in a distributed database system including a plurality of nodes are provided. The method comprising: receiving, by a node of the plurality of nodes, a stream of at least Point-in-Time (PiT) creation events and PiT removal events; receiving a list of committed transaction identifiers (IDs) of committed transactions executed by the distributed database system; inspecting row-versions in the distributed database system to identify unneeded row-versions that can be safely removed, wherein the inspection is performed in part using the stream of PiT creation events and PiT removal events, and the list of committed transaction IDs; and removing the unneeded row-versions identified by the inspection.

Abstract: A system and method for maintaining a persistent key-value store is presented.

Abstract: A database system implementing a concurrency control protocol is provided. The database system includes a node connected through a network to a client; the node comprises: a storage for storing a plurality of data cells; one or more processors; and a memory, the memory containing instructions that, when executed by the one or more processors, configure the node to: receive at least one non-commit statement that is part of a transaction; execute locally tasks included in each of the at least one received statement in an optimistic manner allowing statements of other transactions to independently access same data cells in the database system being modified by tasks of the at least one received statement; and return the client an acknowledgment that the transaction is committed, the acknowledgment is returned upon validation of the transaction, wherein the transaction is validated in a pessimistic manner.

Abstract: A method and system for managing execution of database transactions by facilitating point-in-time image (PIT). The method comprises receiving at least one statement being part of a transaction, the transaction is initiated by a client to be executed on a distributed database system; sending a single request to a sequencer server (SEQ-server) to create at least one PiT, wherein the SEQ-server provides a logical timestamp counter (LTC) value as a timestamp of the PiT; upon creation of the at least one PiT, causing execution of the at least one statement, a PiT provides a state and content of committed data in the distributed database system; upon receiving a commit statement, performing a commitment process of the transaction, the commitment process is based on a commitment timestamp (CMTS) set by the SEQ-server based on an incremented value of the LTC; and returning an acknowledgment of the transaction commitment to the client.

Abstract: A system and method of the device may include during a validation phase of a transaction, identifying conditional conflicts and their corresponding conflicting transactions, where the corresponding conflicting transactions are reading-transactions conflicting with the transaction. In addition, the device may include for each conditional conflict, classifying its state to determine if the transaction can commit, with respect to the conditional conflict, before the corresponding conflicting transaction. The device may include marking the transaction as dependent on the corresponding conflicting transaction when the transaction cannot commit before the corresponding conflicting transaction. Moreover, the device may include placing a commit pause on data cells modified by the transaction, thereby allowing the transaction to commit, when the transaction can commit before any corresponding conflicting transactions.

Abstract: A method may include receiving a statement that is a part of a transaction; determining if the received statement includes at least one predicate; when the received statement includes at least one predicate, performing, for each of the at least one predicate: identifying at least one table-node participating in the execution of a task associated with the received statement; instantiating, by each of the at least one table-node, a conditional read vector (RV)-entry for the at least one predicate; executing the task included in the received statement; and upon receiving a commit statement that is part of the transaction, returning to a client an acknowledgment that the transaction is committed, where the acknowledgment is returned upon validation of the transaction, and where during validation of the transaction, reading-transactions conflicting with the transaction are detected using at least conditional RV-entries instantiated by the at least one table-node.

Abstract: The method and system may include, during an index-validation process on index write operations of a transaction, identifying index-conflicts between a transaction and at least one reading-transaction; for each identified index-conflict, initiating a foreign instantiation to determine if the transaction can commit before the at least one reading-transaction; and upon completing the foreign instantiations on all identified index-conflicts and when validation conditions are met, placing a commit pause on the index-entries modified by the transaction. The method and system may also include initiating the foreign instantiation of a read-vector entry (RV-entry) in a table-node, wherein the RV-entry corresponds to a predicate of a reading-transaction performing an index search on an index node.

Abstract: A system and method for managing execution of database transactions in a non-distributed database system is presented.

Abstract: A system and method of the device may include receiving a commit statement that is part of a transaction, where the transaction is initiated by a client to be executed on the database system. In addition, the device may include validating the transaction in a pessimistic manner by placing a commit pause on data cells modified during the execution of the transaction, where the commit pause enables an atomicity of a distributed transaction commitment. The device may include returning an acknowledgment to the client that the transaction is committed, where the acknowledgment is returned upon validation of the transaction.

Abstract: In one general aspect, a method may include selecting eligible row-versions for inspection. The method may also include inspecting the selected row-versions, where the inspection results in a classification of eligible row-versions as unneeded or reliant. The method may furthermore include marking row-versions classified as unneeded as approved for immediate removal. The method may, in addition, include adding row-versions classified as reliant on cleaner structures. The method may moreover include upon detection of removal of all point-in-times (PiTs) related to a reliant row-version, deleting the reliant row-version, where the detection is performed by monitoring the cleaner structures. Other embodiments of this aspect include corresponding computer systems, apparatus, and computer programs recorded on one or more computer storage devices, each configured to perform the actions of the methods.

Abstract: A method and system for managing execution of database transactions are provided. The method includes receiving at least one statement that is a part of a transaction, wherein the transaction is initiated by a client to be executed on a database system; executing tasks included in each of the at least one received statement in an optimistic manner, wherein the received at least one statement is not a commit statement; and returning the client an acknowledgement that the transaction is committed, wherein the acknowledgement is returned upon validation of the transaction, wherein the transaction is validated in a pessimistic manner, and wherein the at least one received statement is a commit statement.

Abstract: A method for cleaning unneeded row-versions in a distributed database system including a plurality of nodes are provided. The method comprising: receiving, by a node of the plurality of nodes, a stream of at least Point-in-Time (PiT) creation events and PiT removal events; receiving a list of committed transaction identifiers (IDs) of committed transactions executed by the distributed database system; inspecting row-versions in the distributed database system to identify unneeded row-versions that can be safely removed, wherein the inspection is performed in part using the stream of PiT creation events and PiT removal events, and the list of committed transaction IDs; and removing the unneeded row-versions identified by the inspection.

Abstract: A method and system for managing execution of database transactions by facilitating point-in-time image (PIT). The method comprises receiving at least one statement being part of a transaction, the transaction is initiated by a client to be executed on a distributed database system; sending a single request to a sequencer server (SEQ-server) to create at least one PiT, wherein the SEQ-server provides a logical timestamp counter (LTC) value as a timestamp of the PiT; upon creation of the at least one PiT, causing execution of the at least one statement, a PiT provides a state and content of committed data in the distributed database system; upon receiving a commit statement, performing a commitment process of the transaction, the commitment process is based on a commitment timestamp (CMTS) set by the SEQ-server based on an incremented value of the LTC; and returning an acknowledgment of the transaction commitment to the client.

Abstract: A method and system for managing execution of database transactions are provided. The method includes receiving at least one statement that is a part of a transaction, wherein the transaction is initiated by a client to be executed on a database system; executing tasks included in each of the at least one received statement in an optimistic manner, wherein the received at least one statement is not a commit statement; and returning the client an acknowledgement that the transaction is committed, wherein the acknowledgement is returned upon validation of the transaction, wherein the transaction is validated in a pessimistic manner, and wherein the at least one received statement is a commit statement.

Abstract: A database system implementing a concurrency control protocol is provided. The database system includes a node connected through a network to a client; the node comprises: a storage for storing a plurality of data cells; one or more processors; and a memory, the memory containing instructions that, when executed by the one or more processors, configure the node to: receive at least one non-commit statement that is part of a transaction; execute locally tasks included in each of the at least one received statement in an optimistic manner allowing statements of other transactions to independently access same data cells in the database system being modified by tasks of the at least one received statement; and return the client an acknowledgment that the transaction is committed, the acknowledgment is returned upon validation of the transaction, wherein the transaction is validated in a pessimistic manner.