Greetings, Running MonetDB v11.31.11 (Aug2018-SP1), we ran into an issue where queries that have been running quite well, suddenly slowed by about 5x. Looking at the explain, it seems we hit a condition that is preventing mitosis? Copying the tables related to the query seems to restore performance to the previous level, but would be very curious to understand what happened here. What metrics or stats should we be looking at? Changes we see in the plan are as follows: Bad example: sql.tid(X_4:int, "waltest":str, "cmdb":str); Good example: sql.tid(X_4:int, "waltest":str, "cmdb2":str, 0:int, 32:int); Looking at the storage info, the sizes (heap and column), type width and counts look the same between the two tables. Any thoughts or suggestions would be appreciated. - Herman -- Please excuse typos... I can't type.