I have a data import handler that is importing data in full mode from SQL Server. It has one main entity and three sub-entities. Against a good database, it appears to open 4 connections total. One for the main query and the other 3 subqueries just re-use their connections. This works well enough.
However, I tested this against a slower SQL Server and I saw dramatically worse results. Instead of re-using their database, each of the sub-entities is recreating a connection each time the query runs. So, this is resulting in terrible performance. My guess is that it is some sort of timeout. The dataimporthandler is interpreting the slow connection as a dead connection, and re-creating the db connection. However, it is a slow connection (and does return data), but it is not a dead connection. I tried to apply the SOLR-2233 patch to Solr 1.4.1, but that did not seem to have much of an effect.
