System Architecture

Shared-Disk

Query Interface

PartiQL

QLDB supports Amazon’s SQL dialect PartiQL. As its name implies, PartiQL is a small subset of SQL and it supports basic INSERT, SELECT, DELETE, UPDATE, and INNER JOIN. Here’s a list of clauses that PartiQL does not support yet [DISTINCT, EXISTS, HAVING, LIMIT, UNION, INTERSECT, EXCEPT, PIVOT, UNPIVOT, GROUP BY, ORDER BY, LEFT, RIGHT, OUTER JOIN].

Data Model

Document / XML

Amazon QLDB uses a document-oriented data model Ion, which is originally developed by Amazon for internal use (now open source). It is a superset of JSON in terms of types and validation, as it provides richer data types including int, float, decimal, and timestamp. It can also perform built-in validation by predefined Ion Struct, which not only validates data type and range but also regex expressions if specified.

Ion is a strictly value-based model and supports embedded (hierarchical) documents, but not references.

Storage Model

N-ary Storage Model (Row/Record)

QLDB stores records as documents, which internally are serialized Ion objects in binary-encoded form.

Storage Architecture

Disk-oriented