Commands in a command queue are received and scheduled. For each of the commands, scheduling includes determining an age of a command based on an entrance time of the command in the command queue. When the age of the command satisfies a first threshold, marking all other commands in the command queue as not issuable when the command is a deterministic command, and marking all other commands in the command queue as not issuable when the command is a non-deterministic command and the intermediate command queue is not empty. Scheduling the command further includes determining whether the command is a read command and marking the command as not issuable when the command is a non-deterministic read command and the intermediate command queue is empty.