Abstract: A plurality of data records that comprise a data set can be stored in a plurality of main part fragments such that each main part fragment includes a subset of the set of data records. Each fragment of the plurality of main part fragments can be assigned a relative data temperature. A newly arrived data record for storage in the data set can be placed in a delta part, and a merge can be performed to add the newly arrived data record to a corresponding main part fragment. The performing of the merge can occur more quickly if the corresponding main part fragment has a higher relative data temperature than if the corresponding main part fragment has a lower relative data temperature.

Abstract: A database system may provide determination of statistics for a field of a database table. The determination may include determination of whether the field of the table is associated with a check table, and, if the field of the table is associated with a check table, determination of a number of distinct values of the field in the table based on a number of distinct values of the field in the check table.

Abstract: A plurality of operations are executed using first memory (e.g., heap memory, etc.) in a data storage application. During execution, it is determined that one of the operations cannot be executed due to a lack of available first memory. In response, an emergency allocator assigns pre-allocated emergency memory that is separate and distinct from the first memory to the determined operation. The operation can then be completed using this pre-allocated emergency memory. Related apparatus, systems, techniques and articles are also described.

Abstract: A database system may provide determination of statistics for a field of a database table. The determination may include determination of whether the field of the table is associated with a check table, and, if the field of the table is associated with a check table, determination of a number of distinct values of the field in the table based on a number of distinct values of the field in the check table.

Abstract: A data storage application encrypts one or more data pages using a first initialization vector and one or more encryption keys. In addition, the data storage application encrypts one or more converter pages using a second initialization vector and the encryption key(s). The first initialization vector uses the converter page(s) to encrypt the data page(s). The encrypted data page(s) and the converter page(s) are stored to physical storage. Related apparatus, systems, techniques and articles are also described.

Abstract: Storage pages in a data storage application can be designated as having one of a used status, a free status, and a shadow status. The storage pages having the shadow status remain in use but available for conversion to the free status after completion of a savepoint. The storage pages designated to the shadow status can be assigned among at least a first group and a second group. A first savepoint can be invoked during which the storage pages designated to the shadow status and assigned to the first group are converted to the free status, and a second savepoint can be invoked during which the storage pages designated to the shadow status and assigned to the second group are converted to the free status. In this manner, locking of the system during a savepoint is not required. Related methods, systems, and articles of manufacture are also disclosed.

Abstract: A logical page identity for a logical page containing data storage application data can be mapped to a physical storage page location in a storage where the data of the logical page are stored. The mapping as well as additional page data can be retained within a persistence layer accessible to the data storage application. The additional page data can include at least one of a size of the page and a next page linkage indicating a second page that follows the page in a page sequence of related pages. The retained mapping and additional page data can be retrieved from the persistence layer to initiate a page operation on the related pages, and the page operation can be executed on the related pages based on the retrieved mapping and additional page data. Related methods, systems, and articles of manufacture are also disclosed.

Abstract: A memory block that includes a physical storage page holding data of a data storage application in a page buffer can be cached in a page buffer upon the memory block being designated for a change in status from a used status to a shadow status. Upon occurrence of a trigger event, all pages stored in the page buffer can be processed in a first batch process that can include converting each of the pages in the page buffer from the used status to the shadow status and emptying the page buffer. Upon receiving a call to free the pages in the page buffer from the shadow status to a free status without the trigger event occurring, the pages in the page buffer can be converted from the used status directly to the free status in a second batch process. Related methods, systems, and articles of manufacture are also disclosed.

Abstract: A system includes reception of a request for a page location corresponding to a logical page number, determination of a difference between the logical page number and a smallest logical page number of each of a plurality of converter leaf pages descending from a parent converter inner page, determination of a smallest number 2x that is greater than the number of logical page number-to-page location mappings within each one of the plurality of converter leaf pages, right-shifting of a binary representation of the difference x positions to determine a branch index, identification of one of the plurality of converter leaf pages based on the branch index and on an indexed list of converter page identifiers within the parent converter inner page, logically ANDing of the binary representation of the difference with a binary representation of 2x?1 to determine a mapping index of the identified converter leaf page, identification of a mapping of the identified converter leaf page based on the mapping index, and deter

Abstract: A data storage application encrypts one or more data pages using a first initialization vector and one or more encryption keys. In addition, the data storage application encrypts one or more converter pages using a second initialization vector and the encryption key(s). The first initialization vector uses the converter page(s) to encrypt the data page(s). The encrypted data page(s) and the converter page(s) are stored to physical storage. Related apparatus, systems, techniques and articles are also described.

Abstract: A database system receives a request to access one of a plurality of data containers. Such request includes a file identification (ID) corresponding to the requested data container. Using this file ID, metadata associated with the requested data container is accessed. The metadata is stored in a page of page chain and such metadata identifies a location of the requested data container (so that it can be accessed). Thereafter, the metadata is used to enable access to the requested data container. The file ID in the request can encapsulate a page number and at least one index. This page number identifies a page in the page chain storing the metadata and the index identifies a location within the identified page where the metadata can be found. Related apparatus, systems, techniques and articles are also described.

Abstract: A record within a destination virtual file is generated on a destination node of a distributed data storage system. The record comprises (i) a link directed to a partition of a source virtual file stored on a source node and (ii) partition criteria characterizing the partition. The source virtual file is mapped to a chain of linked pages stored in a page buffer of the distributed data storage system and the partitioning criteria is used by at least one of the source node and the destination node to identify data associated with the partition. A request is later received at the destination node to access data defined by the destination virtual file. Data is provided, in response to the request, from the partition of the source virtual file stored on the source node using the link and the partitioning criteria. Related apparatus, systems, techniques and articles are also described.

Abstract: Log entries are recorded in a data storage application (such as an in-memory database, etc.) for a plurality of transactions among nodes in a node hierarchy. The node hierarchy comprises master node having a plurality of slave nodes. Thereafter, at least a portion of the master node log entries are replayed until a first replay position is reached. Next, for each slave node, at least a portion of its respective log entries are replayed until the first replay position is reached (or an error occurs). Subsequently, replay of at least a portion of the log entries of the master node that are subsequent to the first replay position is initiated by the master node in parallel to at least a portion of the replaying by the slave nodes. Related apparatus, systems, techniques and articles are also described.

Abstract: A record within a destination virtual file is generated on a destination node of a distributed data storage system. The record comprises a link directed to a source virtual file stored on a source node. The source virtual file is mapped to a chain of linked pages stored in a page buffer of the distributed data storage system. A request is later received at the destination node to access data defined by the destination virtual file. Data is provided, in response to the request, from the source virtual file stored on the source node using the link. Related apparatus, systems, techniques and articles are also described.

Abstract: A system includes reception of a request for a page location corresponding to a logical page number, determination of a difference between the logical page number and a smallest logical page number of each of a plurality of converter leaf pages descending from a parent converter inner page, determination of a smallest number 2x that is greater than the number of logical page number-to-page location mappings within each one of the plurality of converter leaf pages, right-shifting of a binary representation of the difference x positions to determine a branch index, identification of one of the plurality of converter leaf pages based on the branch index and on an indexed list of converter page identifiers within the parent converter inner page, logically ANDing of the binary representation of the difference with a binary representation of 2x?1 to determine a mapping index of the identified converter leaf page, identification of a mapping of the identified converter leaf page based on the mapping index, and deter

Abstract: A system to load a plurality of converter pages of a datastore into a database cache, the plurality of converter pages comprising a plurality of converter inner pages, and a plurality of converter leaf pages, to allocate a control block in the database cache for each of the plurality of converter inner pages, the control block of a converter inner page comprising a pointer to a control block of a parent converter inner page and a pointer to a control block of each child converter page of the converter inner page, and to allocate a control block in the database cache for each of the plurality of converter leaf pages, the control block of a converter leaf page comprising a pointer to a control block of a parent converter inner page.

Abstract: A physical storage volume can be partitioned into a plurality of master blocks of an equal master block size. Each master block of the plurality of master blocks can be allocated for storage of a single storage page size of a plurality of predefined storage page sizes provided for storage of data by a data storage application. A received page size can be determined for a storage page designated by the data storage application for storage on the physical storage volume, and the storage page can be stored in a free block of a master block of the plurality of master blocks having the single page size equivalent to the received page size. Related methods, systems, and articles of manufacture are also disclosed.

Abstract: Storage pages in a data storage application can be designated as having one of a used status, a free status, and a shadow status. The storage pages having the shadow status remain in use but available for conversion to the free status after completion of a savepoint. The storage pages designated to the shadow status can be assigned among at least a first group and a second group. A first savepoint can be invoked during which the storage pages designated to the shadow status and assigned to the first group are converted to the free status, and a second savepoint can be invoked during which the storage pages designated to the shadow status and assigned to the second group are converted to the free status. In this manner, locking of the system during a savepoint is not required. Related methods, systems, and articles of manufacture are also disclosed.

Abstract: A logical page identity for a logical page containing data storage application data can be mapped to a physical storage page location in a storage where the data of the logical page are stored. The mapping as well as additional page data can be retained within a persistence layer accessible to the data storage application. The additional page data can include at least one of a size of the page and a next page linkage indicating a second page that follows the page in a page sequence of related pages. The retained mapping and additional page data can be retrieved from the persistence layer to initiate a page operation on the related pages, and the page operation can be executed on the related pages based on the retrieved mapping and additional page data. Related methods, systems, and articles of manufacture are also disclosed.

Abstract: A data size characteristic of contents of a related unit of data to be written to a storage by an input/output module of a data storage application can be determined, and a storage page size consistent with the data size can be selected from a plurality of storage page sizes. The related unit of data can be assigned to a storage page having the selected storage page size, and the storage page can be passed to the input/output module so that the input/output module physically clusters the contents of the related unit of data when the input/output module writes the contents of the related unit of data to the storage. Related methods, systems, and articles of manufacture are also disclosed.