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A partition is a division of a logical database or its constituent elements into distinct independent parts. Database partitioning refers to intentionally breaking a large database into smaller ones for scalability purposes, distinct from network partitions which are a type of network fault between nodes. [1]
Horizontal partitioning is a database design principle whereby rows of a database table are held separately, rather than being split into columns (which is what normalization and vertical partitioning do, to differing extents). Each partition forms part of a shard, which may in turn be located on a separate database server or physical location.
A basic technique is to split large tables into multiple partitions based on ranges of values in a key field. For example, the data for each year could be held on a separate disk drive or on a separate computer. Partitioning removes limits on the sizes of a single table.
The PACELC theorem, introduced in 2010, [8] builds on CAP by stating that even in the absence of partitioning, there is another trade-off between latency and consistency. PACELC means, if partition (P) happens, the trade-off is between availability (A) and consistency (C); Else (E), the trade-off is between latency (L) and consistency (C).
NewSQL is a class of relational database management systems that seek to provide the scalability of NoSQL systems for online transaction processing (OLTP) workloads while maintaining the ACID guarantees of a traditional database system.
Disk partitioning or disk slicing [1] is the creation of one or more regions on secondary storage, so that each region can be managed separately. [2]
Data striping is used in some databases, such as Sybase, and in certain RAID devices under software or hardware control, such as IBM's 9394 RAMAC Array subsystem. File systems of clusters also use striping.
The vague adjectives of very and large allow for a broad and subjective interpretation, but attempts at defining a metric and threshold have been made. Early metrics were the size of the database in a canonical form via database normalization or the time for a full database operation like a backup.