# eXtremeSQL Features

> The eXtremeSQL syntax and detailed information for the following topics are provided in separate pages. Please use the links below to view the individual topics:

> Window Functions | Aggregation-like functions that return multiple values
> ARF Functions | Support for eXtremeDB Active Replication Fabric
> Covering Indexes | Covering indexes can significantly improve lookup performance
> Autocheckpoint | Allow the application to "see" the modifications made in the current transaction
> LIMIT | Limit the number of results for a query
> TTL | Support Time-To-Live in SQL
> Parallel query execution | The eXtremeDB runtime implements PARALLEL
> Sequence Parallelism | The eXtremeDB runtime implements parallel processing of sequences through a thread pool
> Functions Preload | Allows the SQL engine to parse and load into memory all UDFs stored in the database
> Shuffle_Join | The classical map-reducing algorithm "shuffle join" is implemented when performing a join between tables
> ANSI Standards | Compliance of eXtremeSQL with ANSI Standards