Sap Se

Sap Ag

Daniel Booss

Ivan Schreter

Robert Kettler

Mehul Wagle

Ismail Oukid

Werner Thesing

Andrei Suvernev

Volkmar Soehner

Thomas Willhalm

Thorsten Glebe

Jaeyoung Choi

Peter Bumbulis

Chul Won Lee

Tobias Scheuer

Dirk Thomsen

Guenter Radestock

Wolfgang Lehner

Alexander Boehm

Frank Renkes

Hendrik C R Lock

Oliver Rebholz

Abdelkader Sellami

Gunter Radestock

Akanksha Meghlan

Daniel Egenolf

Adrien Lespinasse

Stephan Weber

Hendrick C R Lock

Harshada Khandekar

A system for shutting down a process of a database is provided. In some aspects, the system performs operations including tracking, during startup of a process, code locations of a process in the at least one memory. The operations may further include tracking, during runtime of the process and in response to the tracking the code locations, memory segments of the at least one memory allocated to the process. The operations may further include receiving an indication for a shutdown of a process. The operations may further include waking, in response to the indication, at least one processing thread of a plurality of processing threads allocated to a database system. The operations may further include allocating a list of memory mappings to the plurality of processing threads. The operations may further include freeing, by the first processing thread, the physical memory assigned to the processing thread by the memory mappings.

Fast shutdown of large scale-up processes

Receiving a statement including requests for database operations in a secondary database system storing data replicated from a primary database system by replaying transaction output generated by the primary database system; responsive to receiving the statement, requesting an allocation of memory from the secondary database system to support the requested database operations; generating an aggregated statement memory consumption value based on the amount of memory consumed by all statements executing in the secondary database system that are not associated with replaying the transaction logs; determining that the requested allocation of memory in addition to the aggregated statement memory consumption value exceeds a total statement execution memory limit indicating a total amount of memory that may be allocated to all database operations associated with statement execution in a secondary database system, and denying the requested allocation of memory. Related apparatus, systems, techniques and articles are also described.

Database memory management in a high availability database system using limits

A computer-implemented method, system or product, the method comprising receiving, by a memory management system, a first memory request from a first thread in a multi-threaded computing environment, the memory request including a target value associated with a size of memory requested by the first thread; in response to receiving the first memory request, retrieving a header referencing a first node in a linked list data structure having a plurality of connected nodes, the header comprising a first pointer value, referring to a free first memory block, and a first size value associated with a size of the first memory block; reading, by way of an atomic operation, the first pointer value and the first size value from the linked list data structure.

Memory management in a multi-threaded computing environment

A system for allocating memory (e.g., heap) in multi-core processors is provided. In some implementations, the system performs operations comprising receiving, at a shared cache having a plurality of segments, a first data allocation including a plurality of data blocks, and allocating at least a first and second data block from the first allocation. First and second segments in the shared cache can each comprise a plurality of data slots (e.g., of equal length). Allocating the first and second data blocks can include storing the first data block in a data slot of the first segment and storing the second data block in a data slot of the second segment. The plurality of data slots which do not contain data may contain padding, and/or the data slots to which the first and second data blocks are allocated are not adjacent. Related systems, methods, and articles of manufacture are also described.

Memory allocation in multi-core processors

A memory allocator assigns temporary memory limits to each of a plurality of processes requiring memory. Thereafter, at least one assigned temporary memory limit is changed during execution of a corresponding process. Related apparatus, systems, techniques and articles are also described.

Inter-process memory management

A system includes a non-volatile random access memory storing a column store main fragment of a column of a database table, and a processing unit to read the column store main fragment from the non-volatile random access memory. A volatile random access memory storing a column store delta fragment of the column of the database table may also be included, in which the processing unit is to write to the column store delta fragment. According to some systems, the stored column store main fragment is byte-addressable, and is copied from the volatile random access memory to the non-volatile random access memory without using a filesystem cache.

Column store main fragments in non-volatile RAM and the column store main fragments are merged with delta fragments, wherein the column store main fragments are not allocated to volatile random access memory and initialized from disk

Resources are loaded into a resource container in an in-memory database system in which pages are loaded into memory and having associated physical disk storage. Each resource is assigned a new time stamp when such resource is loaded into the resource container. At least some of the references are subsequently accessed and time stamps associated with these accesses resources are selectively updated based on the type of access. These time stamps are later used to evict least recently used resources (as indicated by their time stamps) from the resource container.

Optimized database resource handling

A method for reclaiming memory resources may include segmenting a plurality of memory resources in an in-memory database into a first resource partition and a second resource partition; generating, for the first resource partition, a first heap containing a first plurality of memory resources sorted based on an age of data occupying the first plurality of memory resources; generating, for the second resource partition, a second heap containing a second plurality of memory resources sorted based on an age of data occupying the second plurality of memory resources; and when a shortage of memory resources is detected, identifying, from the first heap, a first memory resource containing a least recently used data, identifying, from the second heap, a second memory resource containing a least recently used data, and reclaiming the first memory resource and/or the second memory resource. Related systems and articles of manufacture are also disclosed.

Reclamation of in-memory database memory resources

A method may include dividing, into a first portion of memory resources and a second portion of memory resources, a plurality of memory resources included in a cache coupled with a database. The plurality of memory resources included in the cache may store data from the database. The first portion of memory resources may be occupied by data assigned to a first weight class. The second portion of memory resources may be occupied by data assigned to a second weight class. The first portion of memory resources may be selected based at least on the first weight class and an age of at least some of the data occupying the first portion of memory resources. In response to the selection of the first portion of memory resources, the first portion of memory resources may be reclaimed. Related systems and articles of manufacture, including computer program products, are also provided.

Reclamation of cache resources

A system includes reception of an instruction to create a data block associated with a portion of a database table in a non-volatile memory system, creation, in response to the instruction to create the data block, of a file associated with the data block in the non-volatile memory system, where a filename of the file comprises an indication that the data block is a temporary block, creation of an entry in a data block map table indicating that the data block is a temporary block, reception of an instruction to commit the data block, and, in response to the instruction to commit the data block, flush data associated with the data block to the file in the non-volatile memory system, rename the file to remove the indication that the data block is a temporary block, and update the entry in the data block map to indicate that the data block is a committed block.

DBMS storage management for non-volatile memory

Disclosed herein are system, method, and computer program product embodiments for defragmentation of persistent main memory (e.g., storage class memory). An embodiment operates by determining that a request to allocate a block of persistent main memory cannot be fulfilled, identifying the largest block of a plurality of free blocks associated with a persistent allocator, and punching a hole at the location of the block within a segment of the persistent main memory. The embodiment further operates by determining that at least one neighboring block of the largest block is also a hole, and coalescing the at least one neighboring block and the largest block.

Defragmentation of persistent main memory

A data recovery system and method are disclosed. Primary data is stored a database in byte-addressable NVRAM, where the database includes one or more persistent tables of data in a byte-addressable, RAM format, and a persistent memory allocator that maps persistent memory pointers of the persistent memory to virtual memory pointers of a virtual memory associated with the database. Secondary data is stored in volatile DRAM. A failure recovery includes recovering the persistent memory allocator, mapping the persistent memory to the virtual memory to recover primary data using their persistent memory pointers, translating the persistent memory pointers to virtual memory pointers, undoing changes to the primary data made by unfinished transactions of the query execution at the time of failure of one of the one or more queries, and reconstructing the secondary data from the primary data.

Growing community of inventors

Wiesloch, Germany

Daniel Booss