Re: [HACKERS] Autovacuum improvements

Alvaro Herrera wrote:
> Alvaro Herrera wrote:
> New version of the patch attached.
> 
> I'll probably apply this tomorrow morning unless there are objections.
> 
> An important difference from the previous patch is that
> DatabaseHasActiveBackends (now renamed to
> DatabaseCancelAutovacuumActivity) cycles through the whole ProcArray
> instead of stopping at the first occurence of a backend in that
> database.  This is to be able to fulfill its mission of cancelling *any*
> autovacuum activity that may be taking place on the database (not just
> the one that happens to be below the first process in the ProcArray).

Is there any chance of a race condition here?  That is, can the launcher 
process start a new autovacuum process against that database that your 
code will miss since it was started after you began your search?