Shard (database architecture)

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Shard" database architecture – news · newspapers · books · scholar · JSTOR (March 2021) (Learn how and when to remove this message)

A database shard, or simply a shard, is a horizontal partition of data in a database or search engine. Each shard may be held on a separate database server instance, to spread load.

Some data in a database remains present in all shards,^[a] but some appears only in a single shard. Each shard acts as the single source for this subset of data.^[1]

Cite error: There are <ref group=lower-alpha> tags or {{efn}} templates on this page, but the references will not show without a {{reflist|group=lower-alpha}} template or {{notelist}} template (see the help page).