In SERVER-47155, a createIndex command waits for the number of concurrent index builds to fall below a certain limit before proceeding. The log message "Too many index builds running simultaneously, ..." is used to indicate that the index build is blocked.

Due to the placement of this log message within the predicate provided to conditional variable, this log message may be printed multiple times depending on how often the Interruptible class evaluates the predicate or wakes up from a sleep.

In some cases, we have observed this log message printed as many as four times within the same millisecond before the condition variable starts the second phase of its wait logic.