On Mon, Sep 26, 2011 at 10:50 AM, Fujii Masao <masao.fu...@gmail.com> wrote:
> Currently, if a reference to an invalid page is found during recovery, > its information > is saved in hash table "invalid_page_tab". Then, if such a reference > is resolved, > its information is removed from the hash table. If there is unresolved > reference to > an invalid page in the hash table at the end of recovery, PANIC error occurs. > > What I'm worried about is that the hash table is volatile. If a user restarts > the server before reaching end of recovery, any information in the > hash table is lost, > and we wrongly miss the PANIC error case because we cannot find any unresolved > reference. That is, even if database is corrupted at the end of recovery, > a user might not be able to notice that. This looks like a serious problem. > No? > > To prevent the above problem, we should write the contents of the hash table > to > the disk for every restartpoints, I think. Then, when the server > starts recovery, > it should reload the hash table from the disk. Thought? Am I missing > something? That doesn't happen because the when we stop the server it will restart from a valid restartpoint - one where there is no in-progress multi-phase operation. So when it replays it will always replay both parts of the operation. -- Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
