Sap Se

Korea Institute of Science and Technology

Hyejeong Lee

Juchang Lee

Chang Gyoo Park

Kyu Hwan Kim

Mihnea Andrei

Hyoung Jun Na

Hyun Joo Lee

Byoung Sung Ahn

Sang Deuk Lee

Hye Jin Lee

Ji Sik Choi

Chang-Gyoo Park

Friedrich Keller

Hyoung-Jun Na

Kyu-Hwan Kim

Implementations of the present disclosure include providing, at each node in a set of nodes of a database system, a table partition of a plurality of table partitions, the plurality of table partitions being provided by partitioning a table using a primary key, providing, at each node in the set of nodes of the database system, a secondary index partition of a plurality of secondary index partitions, each secondary index partition including a replicate table of at least a portion of the table, the plurality of secondary index partitions being provided by partitioning the table using one or more secondary keys, and for at least one operation executed on a table partition, executing a replication protocol to replicate the at least one operation on a secondary index partition that corresponds to the table partition.

Supporting scalable distributed secondary index using replication engine for high-performance distributed database systems

Technologies are provided for reducing or eliminating transaction consistency anomalies that can occur during data replication, such as during database table replication. For example, commit values can be used to coordinate requests so that the requests are not performed on database tables with inconsistent data.

Ensuring snapshot monotonicity in asynchronous data replication

Technologies are described for performing replication within a database environment. Where a database transaction is replicated at multiple replica nodes, a replica node is selected as a coordinator replica node for the transaction. The other replica node or nodes are designated as follower replica nodes for the transaction. A follower replica node sends the coordinator replica node a precommit notification when the follower replica node has precommitted the transaction. The coordinator replica node sends the follower replica node a postcommit notification to commit the transaction when the transaction has been precommitted by all of the replica nodes to which the transaction is to be replicated.

Multi-replica asynchronous table replication

An oldest version timestamp is received from a first database. A current commit timestamp is received from a second database configured to asynchronously replicate the first database. The current global commit timestamp corresponds to a commit transaction executed in the first database and subsequently replicated in the second database. A first test query is then issued to the second database including a request for a current timestamp of the second database. A second test query is issued to the primary database requesting records associated with a target update version that has a target timestamp equal to the current snapshot timestamp. A determination is then made that a first return associated with the first test query and a second return associated with the second test query are identical indicating a successful validation. Related apparatus, systems, techniques and articles are also described.

Validating query results during asynchronous database replication

Disclosed herein are system, method, and computer program product embodiments for synchronizing lost change between a source table and a replica table. An embodiment operates by detecting a restart at a source node or a replica node. Row-ID values of replication log entries are then compared to row-ID column values of rows at a replica table of the replica node. Replication errors at a source table or the replica table are then determined based on the row-ID comparison. The rows of the source table and the replica table are then updated based on the determination.

RowID-based data synchronization for asynchronous table replication

A method for preparing glycidol using glycerol includes mixing glycerol with urea in the presence of at least one zinc-based catalyst selected from the group consisting of Zn(NO), ZnCl, ZnO and Zn(OAc)under a pressure of 0.5-10 kPa at a temperature of 100-170&#xb0; C. to obtain glycerol carbonate; filtering the glycerol carbonate mixed with the zinc-based catalyst through an adsorbent including a polymer resin coordinated with amine groups to separate the zinc-based catalyst and glycerol carbonate from each other; and carrying out reaction of the glycerol carbonate separated from the zinc-based catalyst in the presence of an anion alkali metal salt catalyst that is Na, K, Rb, Cs or a mixture thereof containing at least one anion selected from the group consisting of Cl, Br, I, NO, NOand acetate under a pressure of 0.13-6.67 kPa at a temperature of 140-250&#xb0; C. to obtain glycidol.

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Seoul, South Korea

Hyejeong Lee