Francisco, this NX_SQL_QUEUE_LIMIT is the virtdb agent sql queue limit and the message says this agent(sqlagt:select100) has reaches its limit and now another queue(FETCH) starts. You can think about SQL Q the Q before FETCH Q in virtdb. Usually this means there is DB difficulty(DBMS too busy, network delay etc). You could change this value by adding
@ NX_SQL_QUEUE_LIMIT=1000
(say you want to change to 1000)
in NX.env file. This could make this message pop not that often. Thanks _Chi