Abstract: A method includes storing an anchor row vector identification for an anchor row to a local memory. It is determined whether the anchor row vector identification is visible based on isolation requirements. The anchor row vector identification is accessed upon a determination that the anchor row vector identification is visible, and the row vector identification is re-read from the local memory. It is determined whether the anchor row vector identification has not changed since a start of the accessing. Upon a determination that the anchor row vector identification has not changed, read anchor row fields are returned. A first check history is performed on an anchor row history tuple sequence number (TSN) for the anchor row.

Abstract: One embodiment provides for a method to track replication state and providing quorum visible retrievals. The method includes assigning, by a writer node performing write operations, a sequence number. The sequence number is replicated with a write operation to other replica nodes in an asynchronous fashion thru a first network channel. On a second network channel, a state of a local system is communicated by sending a latest sequence number available that has been hardened to the other replica nodes. A query is obtained by a reader node, and a sequence number limit is selected. Results up to the sequence number limit are returned.

Abstract: A computer-implemented method for operating a database management system which includes a source database and a target database. A database management system is configured for asynchronously replicating data changes of the source database to the target database. The database management system receiving a request to perform a database statement. The method can identify the most recently committed one of a plurality of transactions having been committed in the source database before the receiving of the request. Identifying repeatedly the one of the plurality of transactions having been replicated most recently to the target database. Execution of the requested statement in the target database is delayed until an evaluation of the repeatedly identified most recently replicated transaction returns that the identified most recently committed transaction has been replicated to the target database. After the delaying execution, the method executes the requested statement in the target database.

Abstract: A computer-implemented method for operating a database management system which includes a source database and a target database. A database management system is configured for asynchronously replicating data changes of the source database to the target database. The database management system receiving a request to perform a database statement. The method can identify the most recently committed one of a plurality of transactions having been committed in the source database before the receiving of the request. Identifying repeatedly the one of the plurality of transactions having been replicated most recently to the target database. Execution of the requested statement in the target database is delayed until an evaluation of the repeatedly identified most recently replicated transaction returns that the identified most recently committed transaction has been replicated to the target database. After the delaying execution, the method executes the requested statement in the target database.

Abstract: A computer-implemented method for processing a transaction may include, upon receiving a transaction change request, operating a coordinator to generate a unique transaction identifier for the transaction request, send a data change request along with the unique transaction identifier to sources, and store the unique transaction identifier along with a respective first change count in a transaction status table. The method may also include, upon receiving a query, operating a given source to determine from the transaction status table, a second change count of sources associated with the unique transaction identifier, determine whether the second change count matches the first change count for each source, and when the first and second change counts match in each of the other sources, read data associated with the query from the given source and each source.

Abstract: A computer program product, including: a computer readable storage device to store a computer readable program, wherein the computer readable program, when executed by a processor within a computer, causes the computer to perform operations for logging. The operations include: receiving a transaction including data and a log record corresponding to the data; writing the data to a data storage device; and writing the log record to a log space on a persistent memory device coupled to the data storage device.

Abstract: A method includes logically organizing, by an object hierarchy processor, data objects in a first hierarchy. A portion of the data objects in the first hierarchy logically includes groupings of other data objects. The object hierarchy processor physically organizes the data objects across two or more types of memory in a second hierarchy. Another portion of the data objects in the second hierarchy physically includes groupings of other data objects. Groupings of the data objects in the second hierarchy are dynamically moved across the two or more types of memory. Levels of access of the data objects are tracked using a data structure that maps groupings of the data objects in the first hierarchy onto metadata information including combined access frequencies of the data objects, and current number of accessors to the data objects, in each grouping of the data objects.

Abstract: One embodiment provides for a method to track replication state and providing quorum visible retrievals. The method includes assigning, by a writer node performing write operations, a sequence number. The sequence number is replicated with a write operation to other replica nodes in an asynchronous fashion thru a first network channel. On a second network channel, a state of a local system is communicated by sending a latest sequence number available that has been hardened to the other replica nodes. A query is obtained by a reader node, and a sequence number limit is selected. Results up to the sequence number limit are returned.

Abstract: A method includes storing an anchor row vector identification for an anchor row to a local memory. It is determined whether the anchor row vector identification is visible based on isolation requirements. The anchor row vector identification is accessed upon a determination that the anchor row vector identification is visible, and the row vector identification is re-read from the local memory. It is determined whether the anchor row vector identification has not changed since a start of the accessing. Upon a determination that the anchor row vector identification has not changed, read anchor row fields are returned. A first check history is performed on an anchor row history tuple sequence number (TSN) for the anchor row.

Abstract: A method includes setting, by an update processor, a write latch in a first data structure associated with an object. The first data structure is copied to a storage structure. A history tuple sequence number (TSN) of the first data structure is set to point to a TSN of the copied first data structure. The version identifier is set to point to a transaction identification for the object. Data portions are updated for the first data structure. The version identifier is read from the first data structure. It is determined whether the version identifier of the first data structure is visible for a transaction including isolation requirements. If version identifier of the first data structure is visible, the first data structure is accessed and it is determined whether the version identifier of the first data structure changed since starting the transaction.

Abstract: A computer-implemented method for processing a transaction may include, upon receiving a transaction change request, operating a coordinator to generate a unique transaction identifier for the transaction request, send a data change request along with the unique transaction identifier to sources having respective source identifiers, and store the unique transaction identifier along with the respective source identifiers in a transaction status table. The computer-implemented method may further include, upon receiving a query, operating a given source to determine from the transaction status table, any other sources associated with the unique transaction identifier, determine whether the unique transaction identifier is in each of the other sources, and when the unique transaction identifier is in each of the other sources, read data associated with the query from the given source and each of the other sources.

Abstract: A computer-implemented method for operating a database management system which includes a source database and a target database. A database management system is configured for asynchronously replicating data changes of the source database to the target database. The database management system receiving a request to perform a database statement. The method can identify the most recently committed one of a plurality of transactions having been committed in the source database before the receiving of the request. Identifying repeatedly the one of the plurality of transactions having been replicated most recently to the target database. Execution of the requested statement in the target database is delayed until an evaluation of the repeatedly identified most recently replicated transaction returns that the identified most recently committed transaction has been replicated to the target database. After the delaying execution, the method executes the requested statement in the target database.

Abstract: A computer-implemented method for operating a database management system which includes a source database and a target database. A database management system is configured for asynchronously replicating data changes of the source database to the target database. The database management system receiving a request to perform a database statement. The method can identify the most recently committed one of a plurality of transactions having been committed in the source database before the receiving of the request. Identifying repeatedly the one of the plurality of transactions having been replicated most recently to the target database. Execution of the requested statement in the target database is delayed until an evaluation of the repeatedly identified most recently replicated transaction returns that the identified most recently committed transaction has been replicated to the target database. After the delaying execution, the method executes the requested statement in the target database.

Abstract: A computer-implemented method for operating a database management system which includes a source database and a target database. A database management system is configured for asynchronously replicating data changes of the source database to the target database. The database management system receiving a request to perform a database statement. The method can identify the most recently committed one of a plurality of transactions having been committed in the source database before the receiving of the request. Identifying repeatedly the one of the plurality of transactions having been replicated most recently to the target database. Execution of the requested statement in the target database is delayed until an evaluation of the repeatedly identified most recently replicated transaction returns that the identified most recently committed transaction has been replicated to the target database. After the delaying execution, the method executes the requested statement in the target database.

Abstract: According to an aspect, a database management system (DBMS) is operated to perform data replication. The DBMS includes a source database and a target database. The source database includes a plurality of first tables respectively comprising one or more first columns, and the target database includes a plurality of second tables respectively comprising one or more second columns. Each of multiple ones of the first columns is mapped to one of the second columns, and each one of the second columns is adapted to store replicated data changes of the first column mapped to the second column. Each of the second columns has an assigned update time, the update time being a moment in time when the second column most recently received incremental data changes from its mapped first column. The DBMS operates to process requested database statements while providing data replication.

Abstract: Embodiments of the present invention provide a system, method and computer program products for memory space management for storage class memory. One embodiment comprises a method for information storage in an information technology environment. The method comprises storing data in a storage class memory (SCM) space, and storing storage management metadata corresponding to said data, in the SCM in a first data structure. The method further includes buffering storage management metadata corresponding to said data, in a main memory in a second data structure.

Abstract: Provided are techniques for using parallel inserts to insert into a column store. A list of sub-ranges for a columnar table is created. A change statement for one or more rows to be inserted into the columnar table is received. For each of the received change statements, a sub-range from the list of sub-ranges is identified and data is serially inserted into the identified sub-range of the columnar table, while allowing parallel processing of each change statement for different sub-ranges of the columnar table.

Abstract: A computer-implemented method for processing a transaction may include, upon receiving a transaction change request, operating a coordinator to generate a unique transaction identifier for the transaction request, send a data change request along with the unique transaction identifier to sources having respective source identifiers, and store the unique transaction identifier along with the respective source identifiers in a transaction status table. The computer-implemented method may further include, upon receiving a query, operating a given source to determine from the transaction status table, any other sources associated with the unique transaction identifier, determine whether the unique transaction identifier is in each of the other sources, and when the unique transaction identifier is in each of the other sources, read data associated with the query from the given source and each of the other sources.

Abstract: A computer-implemented method for processing a transaction may include, upon receiving a transaction change request, operating a coordinator to generate a unique transaction identifier for the transaction request, send a data change request along with the unique transaction identifier to sources, and store the unique transaction identifier along with a respective first change count in a transaction status table. The method may also include, upon receiving a query, operating a given source to determine from the transaction status table, a second change count of sources associated with the unique transaction identifier, determine whether the second change count matches the first change count for each source, and when the first and second change counts match in each of the other sources, read data associated with the query from the given source and each source.

Abstract: A first request may be received to update a first set of values. The first set of values may be stored at a first location within a first data page of a database. The first location may be read-only. In response to the receiving of the first request, a first set of records may be inserted into a second data page. The first set of records may include the update of the first set of values. In response to the inserting, a forward pointer may be stored in the first data page that points to the first set of records on the second data page. One or more committed values may be identified on the second data page. In response to the identifying, the one or more committed values may be merged from the second data page to a third data page.