Has this been addressed? A TODO? ---------------------------------------------------------------------------
On Tue, Sep 6, 2011 at 09:49:39AM -0400, Robert Haas wrote: > On Tue, Sep 6, 2011 at 9:45 AM, Heikki Linnakangas > <heikki.linnakan...@enterprisedb.com> wrote: > >> Do you really need to hold the page locks for all that time, or could > >> you cheat? Like... release the locks on the split pages but then go > >> back and reacquire them to clear the flag... > > > > Hmm, there's two issues with that: > > > > 1. While you're not holding the locks on the child pages, someone can step > > onto the page and see that the MISSING_DOWNLINK flag is set, and try to > > finish the split for you. > > > > 2. If you don't hold the page locked while you clear the flag, someone can > > start and finish a checkpoint after you've inserted the downlink, and before > > you've cleared the flag. You end up in a scenario where the flag is set, but > > the page in fact *does* have a downlink in the parent. > > It seems like both of these could be handled by making the code that > repairs the damage insert the downlink into the parent only if it's > not already present. > > -- > Robert Haas > EnterpriseDB: http://www.enterprisedb.com > The Enterprise PostgreSQL Company -- Bruce Momjian <br...@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + It's impossible for everything to be true. + -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
