LMDB is an ultra-fast, ultra-compact key-value data store developed by Symas for the OpenLDAP Project. It uses memory-mapped files, so it has the read performance of a pure in-memory database while still offering the persistence of standard disk-based databases, and is only limited to the size of the virtual address space (it is not limited to the size of physical RAM).
Unnamed un-names unwanted DNS entries. It was written to solve the problem of upstream DNS servers inserting bogus records for NXDOMAINs. It can be used to filter unwanted domain names like ads, porn, time wasters, etc. It is modular, so extensions are easy. Extensions can be written in Lua or compiled as shared objects.
The YB.ORM library aims to simplify writing C++ code that has to deal with SQL databases. The goal is to provide a convenient interface like SQLAlchemy (Python) or Hibernate (Java). The library itself is cross-platform and supports a variety of SQL dialects: SQLite3, MySQL, Postgres, Oracle, and Firebird. Integration with Boost, Qt4, and wxWidgets is built-in. In a typical usage scenario, you would describe your database schema and table relationships in a simple XML-based format, generate SQL code to populate database schema with tables, generate C++ classes, add application-specific logic to the classes, and use these classes in cooperation with the Session object to query objects from the database, create new or modify/delete existing objects, or link and unlink objects using relations. Simple serialization to XML is supported along with connection pooling.
Groonga is a fast and accurate full text search engine based on an inverted index. Newly registered document instantly appears in search results, and updates are allowed without read locks. These characteristics result in superior performance for real-time applications. It is also a column-oriented database management system (DBMS). Compared with well-known row-oriented systems, such as MySQL and PostgreSQL, column-oriented systems are more suited for aggregate queries.
pycms is a minimalist component-based Web Content Management System based on CherryPy. It has most of the goodies of Plone/Zope: Python instead of a PHP security mess, no MySQL can of worms, clean separation of code and content, and the ability to run nicely behind a Web server/cache/load balancer. In addition, it features plain text storage of all site contents and settings in JSON files, effortless theming, and a small memory footprint.