I have recently upgraded our application from solr 3.6 to solr 4.2.1, and I have just started learning about soft commits and partial updates.
Currently I have one indexing node and 3 replicas of the same core, and every modification goes through a dih delta index. This is usually ok but I have some special cases where updates should be made visible very quickly. As I have seen with my first tests - it is possible to send partial updates and soft commits to each replica and to the indexer - and when the indexer gets an hard commit every replica is realligned. Is this the right approach or am I misunderstanding how to use this feature? I don't see soft commit propagation to replicas when sending update to the indexer only: is this true or maybe I haven't changed some configuration files when porting the application to solr4? Giovanni