DataBasin's Select-Identify, an invaluable tool for many working with salesforce.com, showed erratic behaviour: extremely hard to reproduce even by sometimes re-running the same query on the same data set, the operation would just stop without any error in the console log, trapped exception or else.
After extensive debugging I found the problem in the queryMore method of the API implementation in DataBasinKit. If queryMore had to return just one record, it would malfunction.
Technically this happened because the size reported by Salesforce.com in the queryMore is not the size of the objects of the queryMore, but of the original query.
The problem affects thus anything using queryMore: If you would select and had a batch size in download of 500, you would get a problem with 501, 1001, 1501 records and so on. 500 or 502 would just work fine. Combine this that the query size of the selectIdentify is dynamic and you get the idea on how difficult it was to reproduce.
Now it is fixed and the upcoming 0.9 version will have this fixed. All currently released DataBasin versions are affected by this bug.