Re: [HACKERS] Block level parallel vacuum

Hmm, what is a guarantee at a later time the user will get the required number of workers?  I think if the user decides to vacuum, then she would want it to start sooner.  Also, to cancel the vacuum, for this reason, the user needs to monitor logs which don't seem to be an easy thing considering this information will be logged at DEBUG2 level.  I think it is better to add in docs that we don't guarantee that the number of workers the user has asked or expected to use for a parallel vacuum will be available during execution.  Even if there is a compelling reason (which I don't see)  to log this information, I think we shouldn't use more than one message to log (like there is no need for a separate message for cleanup and vacuuming) this information.