Sap Se

Seyeong Bae

Juchang Lee

Joo Yeon Lee

Mihnea Andrei

Stefan A Baeuerle

Yong Sik Kwon

Ruediger Karl

Hyeong Seog Kim

Ji Hoon Jang

Beomsoo Kim

Kyu Hwan Kim

Marcel Birn

Seungho Yoo

Won Wook Hong

Changseob Lee

Youngho Yoo

Techniques and solutions are described for implementing virtual table schemas. A virtual table schema includes a logical pointer that is used to target a table that includes data and is defined according to the virtual table schema. Values assigned to the logical pointer can be used to target tables at different locations, such as in a federated database system or in a cache of a database management system of a central computing system. When data associated with the virtual table is requested, or prior to receiving the request, the data can be stored in a table in the cache. The logical pointer can be updated to reference the cache. If the cache is full, the table can be removed from the cache, and the logical pointer can be updated to reference a table at the federated database system.

Virtual database tables with updatable logical table pointers

Techniques and solutions are described for implementing virtual table schemas. A virtual table schema includes a logical pointer that is used to target a table that includes data and is defined according to the virtual table schema. Values assigned to the logical pointer can be used to target tables at different locations, such as in-memory storage or in dynamic storage of a database management system. The dynamic storage includes an in-memory buffer cache and persistent storage. The logical pointer can be updated to point to the in-memory storage or the dynamic storage, including based on use statistics. Similarly, a table having data for the virtual table can be transitioned between the in-memory buffer cache and the persistent storage, including based on use statistics for the virtual table. A value for the logical pointer can be updated when the table is transferred between the in-memory buffer cache and the dynamic storage.

Methods, systems, and computer-readable storage media for receiving a first storage request indicating a first type of data and a first size, identifying a first sub-space based on the first type, the first sub-space including a dense group of dense segments and a sparse group of sparse segments, and determining that the dense group of the first sub-space is absent a dense segment to store data of the first storage request based on the first size, and in response: determining whether the sparse group of the first sub-space includes a sparse segment to store the data of the first storage request based on the first size, and storing the data of the first storage request to the sparse group of the first sub-space in response to determining that the sparse group of the first sub-space includes a sparse segment to store the data of the first storage request.

Memory allocation and deallocation mechanism to reduce fragmentation and enhance defragmentation performance

A system includes initiation of recovery from a crash of a database instance and, during the recovery, identification of a subset of pages of a memory image of the database instance which are not reusable and replacement of the identified subset of pages with corresponding pages of the savepoint image.

Database recovery using shared memory

Restoring a database image of a secondary database system comprises initializing the database image from a recovery image that includes metadata logs and non-metadata logs, of which at least one metadata log includes an undo log of non-committed data that is applied to the initialized database image. A first pagelist and first indexes are then rebuilt based on first data segments of the database image and the corresponding metadata objects. The database image is then updated by replaying the metadata redo log generated from the undo log, the metadata logs, and the non-metadata logs. Then, a second pagelist and second indexes for the database system are rebuilt based on second data segments of the database image and the corresponding non-metadata objects, while each of the first data segments is statically separated from the second data segments in physical memory space. Related apparatus, systems, techniques and articles are also described.

Physio-logical logging for in-memory row-oriented database system

Improved database consistency and consistency checking may be provided by cross-referenced split data storage for irregular fields using auxiliary pointers. A fixed-size memory slot may be allocated to a database table in a database system, where the fixed-size memory slot has an address. A variable-size memory slot may be allocated to the database table, where the variable-size memory slot has a different address. For an irregular field in the database table, one or more properties of the irregular field may be stored in the fixed-size memory slot. The one or more properties may include a first pointer which may have the address of the variable-size memory slot. For the irregular field in the database table, at least a portion of data of the irregular field and a second pointer, which may have the address of the fixed-size memory slot, may be stored in the variable-size memory slot.

Cross-referenced irregular field storage in databases

A computer implemented method is provided. The method comprises initializing a first database image of a first database system based on a recovery image comprising committed transactions, visible uncommitted transactions, and undo logs associated with the visible uncommitted transactions, undoing the visible uncommitted transactions using the undo logs, generating redo logs from the undo logs, replaying the redo logs to create invisible uncommitted transactions, and after replaying the redo logs, replaying transaction logs received from a second database system. Related apparatus, systems, techniques and articles are also described.

Growing community of inventors

Seoul, South Korea

Seyeong Bae