Best Key-Value Databases for iPad of 2025

What makes eXtremeDB platform independent? - Hybrid storage of data. Unlike other IMDS databases, eXtremeDB databases are all-in-memory or all-persistent. They can also have a mix between persistent tables and in-memory table. eXtremeDB's Active Replication Fabric™, which is unique to eXtremeDB, offers bidirectional replication and multi-tier replication (e.g. edge-to-gateway-to-gateway-to-cloud), compression to maximize limited bandwidth networks and more. - Row and columnar flexibility for time series data. eXtremeDB supports database designs which combine column-based and row-based layouts in order to maximize the CPU cache speed. - Client/Server and embedded. eXtremeDB provides data management that is fast and flexible wherever you need it. It can be deployed as an embedded system and/or as a clients/server database system. eXtremeDB was designed for use in resource-constrained, mission-critical embedded systems. Found in over 30,000,000 deployments, from routers to satellites and trains to stock market world-wide.

LevelDB is a high-performance key-value storage library developed by Google, designed to maintain an ordered mapping between string keys and string values. The keys and values are treated as arbitrary byte arrays, and the stored data is organized in a sorted manner based on the keys. Users have the option to supply a custom comparison function to modify the default sorting behavior. The library allows for multiple changes to be grouped into a single atomic batch, ensuring data integrity during updates. Additionally, users can create a temporary snapshot for a consistent view of the data at any given moment. The library supports both forward and backward iteration through the stored data, enhancing flexibility during data access. Data is automatically compressed using the Snappy compression algorithm to optimize storage efficiency. Moreover, interactions with the external environment, such as file system operations, are managed through a virtual interface, giving users the ability to customize how the library interacts with the operating system. In practical applications, we utilize a database containing one million entries, where each entry consists of a 16-byte key and a 100-byte value. Notably, the values used in benchmarking compress to approximately half of their original size, allowing for significant space savings. We provide detailed performance metrics for sequential reads in both forward and reverse directions, as well as the effectiveness of random lookups, to showcase the library's capabilities. This comprehensive performance analysis aids developers in understanding how to optimize their use of LevelDB in various applications.