Abstract: Technologies are described for facilitating transaction processing within a database environment. A commit protocol provides for the atomic commit or rollback of a transaction that includes an operation that modifies a metadata entity of the database system and one or more other operations that modify metadata entities or data records of the database system. Innovations are provided for detecting and resolving deadlocks that may arise during transaction processing. Innovations are also provided for providing versioning of metadata entities, including invalidating metadata entities cached at a slave node during the commit at a master node of a transaction that creates a new version of the metadata entity.

Abstract: Objects across multiple database manipulation language (DML) redo log records are cached, during continuous replay of redo log records on a secondary system, for the same table partition to enable reuse of such cached objects. Later, these cached objects can be reused as they are accessed during the sequential processing of DML redo records for a specific table partition.

Abstract: Testing a database replication system within a multi-container system architecture comprises receiving a first request for creating a database recovery system within a multi-container system architecture. The multi-container system architecture is configured to contain a plurality of tenant databases and a system database, and the database recovery system includes a primary system and a secondary system. The primary system is then identified from the information in the first request. Upon identification, a first tenant database included in the plurality of tenant databases is determined that corresponds to the identified primary system. Upon determining the first tenant database, a second tenant database of the plurality of tenant database is generated that corresponds to the secondary system, and which is enabled to test replicating information that would otherwise be associated with the first tenant database. Related apparatus, systems, techniques and articles are also described.

Abstract: A computer implemented method for manipulating data comprises receiving log transaction information from a primary database system at a secondary database system and parsing the log transaction information to identify data objects that have been modified on the primary database system. The secondary database system determines whether the data objects are present in main memory on the secondary database system and whether the log transaction corresponds to a data manipulation language (DML) query or a data definition language (DDL) query. If the data objects are not in the main memory and the query is a DML query, they are copied from persistence data volumes to the main memory. The data objects in main memory are modified by replaying the log transactions on the data objects in the main memory. Then, the data objects in the persistence data volumes are modified. Related apparatus, systems, techniques and articles are also described.

Abstract: A computer implemented method for initializing a secondary database system includes receiving table state information from a primary database system at a secondary database system. The table state information includes information identifying which tables had an open operation during a savepoint event. Metadata associated with the tables is parsed to identify table state information from the metadata and a lock is created for each table identified as having an open operation during the savepoint event. Afterwards, log transaction information is sequentially parsed. Related apparatus, systems, techniques and articles are also described.

Abstract: Partitioning of source partitions of a table of a database to target partitions is initiated. Thereafter, a transition partition specification is specified that identifies the source partitions and the target partitions. Data is then moved (e.g., asynchronously moved, etc.) from the source partitions to the target partitions. Concurrently with the moving of the data, operates are handled using the transition partition specification. Subsequently, the source partitions are dropped when all of the data has been moved to the target partitions and there are no open transactions accessing the source partitions. Related apparatus, systems, techniques and articles are also described.

Abstract: A computer implemented method for updating a secondary database includes receiving transaction log information from a primary database system at a secondary database system. The transaction log information comprises a first marker identifying a beginning of an operation comprising a plurality of sub-operations and a second marker identifying an end of the operation. The transaction log information is sequentially parsed, a first marker is identified, and a lock state is created after replaying the first marker to ensure proper serialization of the plurality of sub-operations. The lock state is terminated after replaying the second marker. Related apparatus, systems, techniques and articles are also described.

Abstract: A computer implemented method is provided comprising receiving a group of transaction logs from a first database, allocating transaction logs from the group of transaction logs to a first queue and to a second queue, generating an end-of-group transaction log indicative of an end of the group of transaction logs, allocating the end-of-group log to the first queue and the second queue; replaying transaction logs from the first queue including the end-of-group transaction log allocated to the first queue, replaying transaction logs from the second queue including the end-of-group transaction log allocated to the second queue; and changing visibility of one or more transactions in response to replaying the end-of-group transaction log allocated to the first queue and the end-of-group transaction log allocated to the second queue. Related apparatus, systems, techniques and articles are also described.

Abstract: A method, computer program product and system are provided. The method, computer program product and system execute a process for storing an object in an object container that is stored in a persistency of a disk storage. The object container has size criteria whereby objects meeting the size criteria of the object container can be assigned to the object container. The object container can facilitate storing multiple objects to optimize disk storage usage by facilitating the assigning of multiple objects to the same disk storage page.

Abstract: A database upon opening each of at least one cursor for a transaction, assigns each statement forming part of a transaction a statement sequence number (SSN) involving at least one row of the database. Thereafter, temporary timestamps are assigned to the at least one row using a transaction identifier and the corresponding SSN. Further, active cursors are monitored such that a final timestamp is prevented from being associated with each row until it has no remaining cursors. Related apparatus, systems, techniques and articles are also described.

Abstract: A method, computer program product and system are provided. The method, computer program product and system execute a process for determining a size of an object, the object having raw data that is operable upon by one or more physical operators. If the object is smaller than a threshold size, the object is stored in main memory of an in-memory database system. If the object is equal to or larger than the threshold size, the object is stored in a persistency of a disk storage, where storing the object in a disk storage further includes generating a global container identifier (ID) for the object, the global container ID referencing raw data of the object stored in the persistency of the disk storage.

Abstract: Data replication in a database includes identifying a source database system. The source database includes a main index file and a delta log file. To create a replica, one or more symbolic links to the source database system are generated. The symbolic links identify a path to a physical location of the source database. A replica of the source database is generated based on the symbolic links. The replica includes a copy of the main index file and delta log file. Information associated with the replica and the symbolic links is stored in a recovery log. Replica are provided transparently to most database engine components by re-using partitioning infrastructure. Components “see” replica as tables with a single partition; that partition is a local replica.

Abstract: Disclosed herein are system, method, and computer program product embodiments for altering the data type of a column in a database. An embodiment operates by converting an original dictionary associated with a column into a new dictionary. The new dictionary stores the values of the original dictionary using a different data type. An index vector containing the keys of the original dictionary is then updated to contain the associated keys of the new dictionary. Because the size of the original dictionary is often substantially smaller than the number of rows in the associated column, this dictionary conversion decreases the computation cost to the database system of altering the data type of the column and reduces or even minimizes database downtime for users.

Abstract: A system includes reception of a first query from a client device at a first database node of a database instance comprising two or more database nodes, determination of a second database node of the two or more database nodes associated with the first query, compilation of the first query at the first database node to generate first compiled code, and transmission of the first compiled code and a first identifier of the second database node from the first database node to the client device.

Abstract: Partitioning of source partitions of a table of a database to target partitions is initiated. Thereafter, a transition partition specification is specified that identifies the source partitions and the target partitions. Data is then moved (e.g., asynchronously moved, etc.) from the source partitions to the target partitions. Concurrently with the moving of the data, operates are handled using the transition partition specification. Subsequently, the source partitions are dropped when all of the data has been moved to the target partitions and there are no open transactions accessing the source partitions. Related apparatus, systems, techniques and articles are also described.

Abstract: Systems, methods and computer program product embodiments for providing version garbage collection using snapshot lists are disclosed herein. Version garbage collection using snapshot lists includes storing, by at least one processor, versions of a record in a database table, the record comprising a record value and a version timestamp, storing, by the at least one processor, active snapshots in two levels of active snapshot lists, an active snapshot comprising a transaction identifier and a snapshot timestamp, determining, by the at least one processor, a minimum active snapshot from the active snapshots in the two levels of active snapshot lists and deleting, by the at least one processor, versions of the record having a version timestamp earlier than a snapshot timestamp of the minimum active snapshot.

Abstract: A computer-implemented method, a computer program product, and a system are provided. A transaction master for each of a plurality of transactions of a database is provided. Each transaction master is configured to communicate with at least one transaction slave to manage execution a transaction in the plurality of transactions. A transaction token that specifies data to be visible for the transaction on the database is generated. The transaction token includes a transaction identifier for identifying whether the transaction is a committed transaction or an uncommitted transaction. The transaction master is configured to update the transaction token after execution of the transaction. A determination whether the transaction can be executed on the at least one transaction slave without accessing data specified by the transaction token is made. The transaction is executed on the at least one transaction slave using a transaction token stored at the at least one transaction slave.

Abstract: A system includes reception of a first query from a client device at a first database node of a database instance, determination of routing information associated with the first query, compilation of the first query at the first database node to generate first compiled code, transmission of the first compiled code and the routing information to the client device, reception of the compiled code from the client device at a second database node, determination, at the second database node, that data associated with the compiled query is associated with a third database node, transmission of the compiled code from the second database node to the third database node, reception of query results at the second database node from the third database node, and transmission of the query results and an indication to update the routing information from the second database node to the client device.

Abstract: A system includes reception of a first query from a client device at a first database node of a database instance comprising two or more database nodes, determination of a second database node of the two or more database nodes associated with the first query, compilation of the first query at the first database node to generate first compiled code, and transmission of the first compiled code and a first identifier of the second database node from the first database node to the client device.

Abstract: A system includes reception of a first query from a client device at a first database node of a database instance comprising two or more database nodes, determination of a second database node of the two or more database nodes associated with the first query, compilation of the first query at the first database node to generate first compiled code, and transmission of the first compiled code and a first identifier of the second database node from the first database node to the client device.