Architecture

Understanding how Vertica works helps you effectively design, build, operate, and maintain a Vertica database. This section assumes that you are familiar with the basic concepts and terminology of relational database management systems and SQL.

Column storage

Vertica stores data in a column format so it can be queried for best performance. Compared to row-based storage, column storage reduces disk I/O, making it ideal for read-intensive workloads. Vertica reads only the columns needed to answer the query. Columns are encoded and compressed to further improve performance.

Vertica uses a number of different encoding strategies, depending on column data type, table cardinality, and sort order. Encoding increases performance because there is less disk I/O during query execution. In addition, you can store more data in less space.

Compression allows a column store to occupy substantially less storage than a row store. In a column store, every value stored in a projection column has the same data type. This greatly facilitates compression, particularly in sorted columns. In a row store, each value of a row can have a different data type, resulting in a much less effective use of compression. The efficient storage methods that Vertica uses allow you to maintain more historical data in physical storage.

Projections

A projection consists of a set of columns with the same sort order, defined by a column to sort by or a sequence of columns by which to sort. Like an index or materialized view in a traditional database, a projection accelerates query processing. When you write queries in terms of the original tables, the query uses the projections to return query results. For more information, see Projections.

Projections are distributed and replicated across nodes in your cluster, ensuring that if one node becomes unavailable, another copy of the data remains available. This redundancy is called K-safety.

Automatic data replication, failover, and recovery provide for active redundancy, which increases performance. Nodes recover automatically by querying the system.

Eon and Enterprise Modes

A Vertica database runs in one of two modes: Eon or Enterprise. Both modes can be deployed on-premises or in the cloud. In Eon Mode, compute and storage are separate; the database uses shared communal storage, and you can add or remove nodes or subclusters based on demand. In Enterprise Mode, each database node has a share of the data and queries are distributed to take advantage of data locality. Understanding the differences between these modes is key. See Eon vs. Enterprise Mode.