Huawei Cloud Computing Technologies Co., Ltd.

Huawei Technologies Co., Limited

Per-Ake Larson

Alexandre Depoutovitch

Chong Chen

Jack Hon Wai Ng

Xun Xue

Robin Grosman

Cong Guo

Timothy James Zeyl

Qi Cheng

A method of incorporating a bloom filter (BF) into cost-based bottom-up query optimization includes: receiving a query including a request to join at least two data tables that include a first data table and a second data table; generating, in response to the request, at least two query plans that includes a first query plan including subplans to: create the BF based on the second data table, apply the BF to the first data table for filtering data of the first data table before the first data table is joined with another data table, and join the first data table with the another data table; submitting the at least two query plans to a cost-based bottom-up optimizer to obtain a target query plan; and providing, as a response to the received query, a set of data that is retrieved from a data retrieval system by executing the target query plan.

Method of incorporating bloom filter into cost-based bottom-up query optimization and computing device

A method of managing locks in a database is performed by a row lock manager of a database master. The method includes receiving, from a transaction executing on the database master, a row lock request for a row in the database. The row lock request includes a page in the database where the row is located. The row lock request also includes a row lock mode of sufficient strength to perform the transaction. Then, sending, to a page lock manager, a request for a covering lock of the page. The request specifies a page lock mode of sufficient strength to satisfy the row lock mode. Also, receiving, from the page lock manager, a grant of the page lock. The page lock includes information on row locks of rows located in the page. Then, granting, to the transaction, the row lock.

Method and apparatus for fine-grained hierarchical locking in a multi-master database system

An apparatus is disclosed. The apparatus may be implemented in a database node or a storage node and includes one or more processors and memory storing instructions for causing the processor to perform a number of operations. Responsive to a page write request, the apparatus determines an identifier corresponding to the requested page, sends component blocks corresponding to the page to a storage node for appending to an append-only storage log of the storage node, receives the physical location of the stored component blocks, and associates the physical storage location of the stored component blocks with the logical identifier corresponding to the page.

Systems and methods for database management using append-only storage devices

A logical clock is implemented in networked nodes. Messages between nodes can include either a scalar timestamp or a vector timestamp. The scalar timestamp leads to an overhead reduction, and nodes can select whether to send a scalar or vector timestamp depending on requirements. Message recipients update their logical clock vector differently depending on whether the scalar or vector timestamp is received. Applications to multi-master databases are also provided. The clock conforms to Lamport clock requirements when the scalar timestamp is sent, and conforms to both Lamport and vector clock requirements when the vector timestamp is sent.

Vector-scalar logical clock and associated method, apparatus and system

A method of reducing write amplification in an append-only memory store of data records, by which the store is subdivided into streams, each of which for storing records having an update frequency within a variable range of update frequencies. By defining an update frequency that does not rely on time, statistical methods can be used to select the streams in which data records can be written. The range of update frequencies of each stream can be fixed or variable and based on the stored records. The memory allocated to each stream can be determined based on numerically solving an optimization problem that determines the write amplification resulting from different memory allocations in the streams.

Compaction policies for append-only stores

Methods and systems are described for managing a shared database. One or more processing nodes may access a shared database. A common log node may manage the shared database. The common log node may validate database operations requested by the one or more processing nodes. During validation, the common log node may detect conflicts that occur between database operations requested by the one or more processing nodes.

Systems and methods for managing a shared database

A method includes receiving an indication of a change to a page of a database and adding a new log record corresponding to the page to a common log comprising log records, the new log record describing the change made to the page and assigned a distinct version number. The method further includes synchronously writing the new log record to each log store replica in a set of log store replicas, and asynchronously writing the new log record to all page store replicas for the page to update the page that is stored on each of the page store replicas, where each store replica for the page serves reads for the page. In response to receiving, from a predetermined number of the page store replicas, an acknowledgement of the writing of the log record, discarding the new log record from the common log.

System and method for replicating data in distributed database systems

Systems and methods for switching a data access synchronization strategy for a data structure are provided. Workload characteristics of one or more threads of execution access the data structure are monitored. A target data access synchronization strategy is determined. If the current strategy is different than the target strategy, the current strategy is switched to the target data access synchronization strategy for the data structure.

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Etobicoke, Canada

Per-Ake Larson