Pervasync just released a new version (6.0.2) of its sync framework that supports synchronization of local PosrgreSQL databases as well as Android/iOS SQLite databases with central PosrgreSQL databases. That's in addition to the already supported Oracle, MySQL and SQL Server databases.
Synchronization could be two-way, meaning writes can be done on both local and central databases. Change capture, conflict detection and resolution are built in to the core of the sync framework.
The signature feature of the framework is that it allows you to sub-set the central server data using free form SQL queries with parameters. Each user-device could sync shared as well as private data with central databases.
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