On Wed, Aug 5, 2015 at 8:30 AM, Pavan Deolasee <pavan.deola...@gmail.com> wrote: > I actually even thought if we can define some macros or functions to work on > atomic list of PGPROCs. What we need is: > > - Atomic operation to add a PGPROC to list list and return the head of the > list at the time of addition > - Atomic operation to delink a list from the head and return the head of the > list at that time > - Atomic operation to remove a PGPROC from the list and return next element > in the list > - An iterator to work on the list.
The third operation is unsafe because of the A-B-A problem. That's why the patch clears the whole list instead of popping an individual entry. > This will avoid code duplication when this infrastructure is used at other > places. Any mistake in the sequence of read/write/cas can lead to a hard to > find bug. > > Having said that, it might be ok if we go with the current approach and then > revisit this if and when other parts require similar logic. Yeah, I don't think we should assume this will be a generic facility. We can make it one later if needed. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
