On Wed, Aug 6, 2014 at 09:24:17PM +0000, Matthew Kelly wrote: > The following is a real critical problem that we ran into here at TripAdvisor, > but have yet figured out a clear way to mitigate. > > TL;DR: > Streaming replicas—and by extension, base backups—can become dangerously broken > when the source and target machines run slightly different versions of glibc. > Particularly, differences in strcoll and strcoll_l leave "corrupt" indexes on > the slave. These indexes are sorted out of order with respect to the strcoll > running on the slave. Because postgres is unaware of the discrepancy is uses > these "corrupt" indexes to perform merge joins; merges rely heavily on the > assumption that the indexes are sorted and this causes all the results of the > join past the first poison pill entry to not be returned. Additionally, if the > slave becomes master, the "corrupt" indexes will in cases be unable to enforce > uniqueness, but quietly allow duplicate values. No surprise; I have been expecting to hear about such breakage, and am surprised we hear about it so rarely. We really have no way of testing for breakage either. :-( -- Bruce Momjian <bruce@xxxxxxxxxx> http://momjian.us EnterpriseDB http://enterprisedb.com + Everyone has their own god. + -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
