Hi, Till I am trying to resolve my business problem I discovered the segfault bug which I have reported in MonetDB bug tracking system. I believe Monetdb is great product and team is moving in right direction utilizing latests advances in technology. Nevertheless my "business" problem is to build OHLC Time Series for longer time frame from shorter ohlc time series. I need partition by interval (5 minutes, 30 minutes, 1 hour, 1 day) and get first record of open, max of high, min of low and last of close from let's say 1 minute ohlc series. In postgresql there are 2 functions: first_value and last_value, which allows to do exactly this. Are there any function/approach/techniques which could be utilized to have the same results in MonetDB, I could do this aggregation on client side but this way I will not utilize DB potential and mainly the network traffic will be prohibitive for the solution. I am sure this question is already addressed somewhere, but I couldn't find, the solution should be trivial and pretty standard but I no luck on my side, if you push me in right directly I will really appreciate. Thank you in advance!John