1. VoltDB：
VoltDB是分布式的内存中NewSQL RDBMS和使用无共享架构的符合ACID的RDBMS。该数据库由Michael Stonebraker，Sam Madden和Daniel Abadi设计。最初，VoltDB数据库包括群集吞吐量和延迟以及CPU和内存使用情况的图表。它基于H-Store，并随着多核服务器上每CPU核心数的增加而扩展。
2. XAP：
XAP是用于任务关键型应用程序的高性能内存数据网格，并提供一组基本的数据存储功能，例如事务，索引和查询语言(类似SQL的查询)。它是用于安装和分发应用程序软件的文件格式。
XAP和VoltDB之间的区别：
| S.No. | XAP | VoltDB |
|---|---|---|
| 1 | It is developed by Gigaspaces Technologies and initially released on 2000 and current release on June 2019. | It is developed by VoltDB Inc. and initially released on 2010 and current release on April 2019. |
| 2 | Its primary database model is Document store and Key-value store and its secondary database models isObject oriented DBMS. | Its primary database model is Relational DBMS. |
| 3 | Its server operating systems of XAP Linux, macOS, Solaris, Windows. | Its server operating systems of VoltDB is Linux, OS X. |
| 4 | It supports GigaSpaces LRMI, Hibernate, JCache, JDBC, JPA, ODBC, RESTful HTTP API, Spring Data. | It supports Java API, JDBC, RESTful HTTP/JSON API. |
| 5 | XAP has ACID (Atomicity, Consistency, Isolation, and Durability) concepts transaction concepts. | Transaction concepts VoltDB is ACID (Atomicity, Consistency, Isolation, and Durability). |
| 6 | Replication methods of XAP- Master-master replication and Master-slave replication. | Replication methods of VoltDB is Master-master replication and Master-slave replication. |
| 7 | Partitioning methods of XAP is Sharding. | It doesn’t holds sharding partitioning methods. |
| 8 | It supports .Net, C++, Java programming languages. | It supports C#, C++, Erlang, Go, Java, JavaScript, PHP, Python programming languages. |
| 9 | It has Immediate Consistency concept. | It doesn’t holds Consistency concept. |
| 10 | Implementation language of XAP is Java, C++, .Net | Implementation language of VoltDB is Java, C++. |