Sap Se

Ji Hoon Jang

Yong Sik Kwon

Hyeong Seog Kim

Seyeong Bae

Juchang Lee

Sang Kyun Cha

Jaeyun Noh

Seungho Yoo

Won Wook Hong

Beomsoo Kim

Jung Hyun Park

Byung Sun Yoon

Seung Kwon You

Eun Kyoung Jun

Won Jin Yun

Junpeng Liu

Zhifeng Xu

Gyu Man Park

Jang Bo Lee

Da Ryeon Son

Wei Wei Gao

Phil Jun Kang

Won Jun Hong

In Yong Kim

Yu Gao

Jie Zheng

Disclosed techniques and solutions can provide improved snapshot replication. Typically, an initial replica obtained using snapshot replication is periodically updated. However, the update process can unnecessarily consume computing resources if data in a source data object has not changed with respect to data in a replica data object. Disclosed techniques check to determine whether a snapshot replica is out of date before obtaining a new snapshot. The checks can be performed on manual request or on the occurrence of triggers, such as receiving a query that accesses the replica data object or according to a schedule. Information for current and prior versions of the remote data object can be compared to determine whether a replica is out of date, such as digest values of contents of the remote data object or timestamps associated with the remote data object.

Change-aware snapshot replication

Systems and methods include determination of a first encryption key associated with a data page of a row store database table stored in a volatile memory, based on a header of the data page, encryption of a body of the data page using the first encryption key, and storage of an encrypted data page comprising the header and the encrypted body in a persistent storage system.

Native multi-tenant row table encryption

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

Methods, systems, and computer-readable storage media for determining that a first transaction results in a first version of data stored in a page in a database system, the first version being stored in a version space and the data being stored in a table space, in response to the first version, providing a version table for the page, the version table including a set of cells each cell corresponding to a record in the page, setting a version table pointer of the page to point to the version table, and setting a version pointer of a first cell to point to the first version in the version space, the first cell corresponding to a record of the data in the page.

Version table scheme for fast version space access

Methods, systems, and computer-readable storage media for online defragmentation of memory in database systems by applying an IX-lock to each table having data stored in a marked page in a set of marked pages, generating a record map including key-value pairs, each being associated with a record location in a marked page, a value of each key-value pair initially set to a first value, iteratively executing the online defragmentation to delete data from marked pages and add the data to non-sparse pages, at least one iteration including applying a try-lock to a record in a marked page, and at iterations of the online defragmentation, updating the record map to change the value of at least one key-value pair from the first value to the second value, the second value representing that data of a marked page has been deleted from the marked page and added to a non-sparse page.

Efficient and non-disruptive online defragmentation with record locking

Technologies are described for restarting an application while maintaining data in memory (e.g., using shared memory). For example, shared memory can be associated with an application. The shared memory can also be associated with a holder process to maintain the shared memory from the time the application stops to the time the application starts again. When the application starts, the shared memory can be associated with the started application. In addition, restart of in-memory databases can be provided using shared memory. For example, in-memory data can be maintained when a database process or database management system stops and starts (e.g., during a restart).

Fast restart of applications 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

Growing community of inventors

Seongnam-si, South Korea

Ji Hoon Jang