The pages in this section introduces some of the key concepts in Materialize:

Concept	Description
Clusters	Clusters are isolated pools of compute resources for sources, sinks, indexes, materialized views, and ad-hoc queries.
Sources	Sources describe an external system you want Materialize to read data from.
Views	Views represent a named query that you want to save for repeated execution. You can use indexed views and materialized views to incrementally maintain the results of views.
Indexes	Indexes represent query results stored in memory.
Sinks	Sinks describe an external system you want Materialize to write data to.
Snapshotting	The initial sync of a source’s data from an upstream system, before the source can serve queries.
Hydration	Hydration is the reconstruction of an object’s in-memory state by reading from Materialize’s storage layer; hydration does not read from the upstream system.
Reaction Time	Measures how quickly a system can reflect a change in input data and return an up-to-date query result. Defined as the sum of data freshness and query latency.

Refer to the individual pages for more information.