Abstract: In an approach to online reorganization of database tables with concurrent updates using virtual partitions, responsive to receiving a table to reorganize, rows of the first table are selected, where the rows of the first table create a first virtual partition. A memory for a second virtual partition is allocated, where the second virtual partition is appended to a second table. A union view is created comprising a union of remaining rows of the first table with the second table, where the remaining rows of the first table have not been copied to the second table. The first virtual partition is copied into the second virtual partition. Responsive to receiving queries before copying the first virtual partition into the second virtual partition is complete, the queries are allowed to access the union view.

Abstract: The present disclosure relates to a problem management method for a user system. A method may include detecting an error in the user system. A signed package may be provided in accordance with the detected error, wherein the package comprises at least a script. The user system may verify the authenticity of the package using a signature of the package, and may execute the script if the package is authentic.

Abstract: A computer implemented method comprises receiving at least one log record. A type of operation performed in a source database system may be determined based on the log record. Based on the type of operation, an update strategy may be selected from a set of pre-defined update strategies, wherein the update strategy specifies a sequence of replication operations to be performed in order to apply changes described in the at least one log record to a target database system.

Abstract: Approaches presented herein enable replicating data records between a source database and a target database. More specifically, for a batch of change records in a table received from the source database, a first estimated replication duration needed to apply the batch as a bulk change to the target is determined. For the same batch, a second estimated replication duration needed to apply a set of changes in a single row of the table to the target is determined based on time penalties for each column in the row. A threshold quantity of rows at which the first duration equals a summed total of second durations for the quantity is calculated. The bulk change is selected if a number of rows in the batch exceeds the threshold. Applying change records singly is selected if the number of rows in the batch is less than the threshold.

Abstract: A database-management system (DBMS) archives a record of a database table by updating the record's unique “Archived” field. This indicates that the record should be considered to have been archived despite the fact that the record has not been physically moved to a distinct archival storage area. When a query requests access to the table, the DBMS determines whether the query requests access to only archived data, only active data, or both. If both, the DBMS searches the entire table. Otherwise, the DBMS scans each record's Archived field to consider only those records that satisfy the query's requirement for either archived or active data. If the DBMS incorporates Multi-Version Concurrency Control (MVCC) technology, the DBMS combines this procedure with MVCC's time-based version-selection mechanism.

Abstract: A computer-implemented system and method process insertions into a target table of a target database system. A single query language INSERT statement is received that is related to a source partition of a source table in a source database system that identifies a block of data (BOD), having a partition identifier (PID), to be inserted into the target table. The INSERT statement contains no literal PID. Responsive to receiving the INSERT statement, a processor receives the BOD from the source table via a data stream, and inserts the BOD into the target table. This reduces the overhead associated with using an INSERT statement to insert multiple rows of data into a target table.

Abstract: Aspects of the present invention disclose a method, computer program product, and system for character encoding. The method includes one or more processors receiving a first query involving an attribute. The first query utilizes encoded in accordance with a first encoding scheme. The method further includes one or more processors identifying a table comprising values of the attribute in compressed format. The method further includes one or more processors creating at least one dictionary, the dictionary mapping a compressed value of the attribute to a corresponding uncompressed value that is encoded in accordance with the first encoding scheme. The method further includes one or more processors storing the dictionary in a cache using a predefined cache management policy of the cache.

Abstract: A method comprises receiving a stream of change log records from a source database system; generating change statistics based on a number of pending changes per table partition according to the change log records; estimating, based on performance statistics, a first amount of time for applying the pending changes to a target database system using an incremental update path; estimating, based on the performance statistics, a second amount of time for applying the pending changes to the target database using a bulk update path; dynamically selecting, based on comparison of the first amount of time with the second amount of time, one of the incremental update path and the bulk update path for applying the pending changes to the target database system; and applying the pending changes to the target database system using the selected update path.

Abstract: In an approach to online reorganization of database tables with concurrent updates, a second table is created, where the second table has the same schema as the first table. A union of the first table and the second table is projected to create a view, where the view allows table data to be queried and modified while the database table reorganization is performed. Responsive to one or more running replication transactions completing, the database table reorganization is executed. Responsive to receiving a query, the query is allowed to access the view.

Abstract: In an approach for executing a set of one or more database transactions in a database system, a processor provides a detection storage configured such that an entry of a database transaction that is stored in the detection storage is automatically deleted in case the database transaction ends, wherein the database transaction comprises a set of operations. For each database transaction of a set of database transactions: a processor adds an entry in the detection storage and a processor executes the database transaction, the execution comprising for at least one operation of the set of operations: executing the at least one operation, determining that the detection storage is empty based on the detection storage not comprising at least the entry of the database transaction, and responsive to determining that the detection storage is empty, determining, by one or more processors, that the database transaction has ended.

Abstract: The present disclosure relates to a computer implemented method for loading data in a target database system. The method comprises: determining that a load of a source table is expected to occur in the target database system. A future target table may be provided in advance in accordance with a defined table schema, and thereafter a load request for loading the source table may be received. Data of the source table may be loaded into the future target table.

Abstract: A method for linking a selected portion of the data stored in a source database to a set of target database(s), determining that a crash of the source database has occurred, and restoring a latest database state of the source database, with the restoration including: triggering a remote recovery process, and restoring data of the selected portion in the source database from: copy(ies) of data entries stored in one, or more, target database(s) of the set of target database(s), and records from a recovery log file of the source database for data entries that have a later timestamp than corresponding copies of the data entry(ies) as stored in the target database(s) of the set of target database(s).

Abstract: A database-management system (DBMS) archives a record of a database table by updating the record's unique “Archived” field. This indicates that the record should be considered to have been archived despite the fact that the record has not been physically moved to a distinct archival storage area. When a query requests access to the table, the DBMS determines whether the query requests access to only archived data, only active data, or both. If both, the DBMS searches the entire table. Otherwise, the DBMS scans each record's Archived field to consider only those records that satisfy the query's requirement for either archived or active data. If the DBMS incorporates Multi-Version Concurrency Control (MVCC) technology, the DBMS combines this procedure with MVCC's time-based version-selection mechanism.

Abstract: Methods and systems for generating database statistics. Table statistics in a metadata catalog of a source database system are observed, statistics generation costs utilizing a target database system are estimated, and source statistics generation costs utilizing a source database system are estimated. The statistics generation costs are compared and statistics generation queries by the target database system are triggered in response to the statistics generation costs utilizing the target database system having a predefined relationship with the source statistics generation costs utilizing the source database system. The statistics generation queries are performed by the target database system in response to the triggering by the source database system. The generated statistics are sent from the target database system to the source database system, the table statistics in a metadata catalog are updated based on the generated statistics, and the updated table statistics are used to optimize a query plan.

Abstract: A method for maintaining linked databases including a source database and a target database, maintaining first metadata in a recovery log file of the source database, maintaining second metadata that identifies portions of data that are replicated from the source database to the target database as part of the selected partitions of the selected tables, receiving an indication that a crash of the source database has occurred, determining a first recovery metric value for recovering the source database's, determining a second recovery metric value for recovering the source database's data from the target database based on the second metadata, and determining whether to recover the source database's data from the recovery log file of the source database or from the target database based on a comparison of the determined first recovery metric value and the second recovery metric value.

Abstract: The invention relates to computer-implemented method for updating a target table with changes introduced into a source table. New data records are stored into partitions of the source table. An incremental update module copies the new data records from the source table into the target table, thereby assigning a new target partition ID contained within a first value domain to each copied data record. A view specifies a set of visible partition IDs as a union of the first value domain and of a current target partition ID set and allows the execution of database queries selectively on target table partitions having assigned a target partition ID that is element of the visible partition ID set. A batch update module performs an atomic batch update operation that comprises copying partitions of the source table into a respective new partition in the target table.

Abstract: The present disclosure relates to a method for enforcing constraints on data in a data processing system. The method comprises providing a set of constraints on the data. A first data update request may be received at the transactional engine and executes on the first dataset. A second data update request associated with the received data update request is determined and sent by the transactional engine to the analytical engine. The analytical engine executes the second data, resulting in a set of changes in the second dataset. The transactional engine commits the update of the first dataset before or after receiving the results of the checking of the set of constraints. The update on the first dataset is aborted by the transactional engine in response to receiving the results of the checking of the set of constraints, wherein the results indicate that the set of constraints are not met.

Abstract: Methods and systems for generating database statistics. Table statistics in a metadata catalog of a source database system are observed, statistics generation costs utilizing a target database system are estimated, and source statistics generation costs utilizing a source database system are estimated. The statistics generation costs are compared and statistics generation queries by the target database system are triggered in response to the statistics generation costs utilizing the target database system having a predefined relationship with the source statistics generation costs utilizing the source database system. The statistics generation queries are performed by the target database system in response to the triggering by the source database system. The generated statistics are sent from the target database system to the source database system, the table statistics in a metadata catalog are updated based on the generated statistics, and the updated table statistics are used to optimize a query plan.

Abstract: Approaches presented herein enable replicating data records between a source database and a target database. More specifically, for a batch of change records in a table received from the source database, a first estimated replication duration needed to apply the batch as a bulk change to the target is determined. For the same batch, a second estimated replication duration needed to apply a set of changes in a single row of the table to the target is determined based on time penalties for each column in the row. A threshold quantity of rows at which the first duration equals a summed total of second durations for the quantity is calculated. The bulk change is selected if a number of rows in the batch exceeds the threshold. Applying change records singly is selected if the number of rows in the batch is less than the threshold.

Abstract: Managing concurrent accesses by a set of tasks to a shared resource of a computer system. Synchronizing the set of tasks for assigning and releasing a resource according to a predefined access period with flexibility of providing an extended access period where an external task is not detected during the predefined access period. Where an extended access period is provided, resynchronizing is performed, and the external task is identified and access is prevented when the external task is determined to be a particular type of task.