On 26 March 2014 15:08, Dang Minh Huong <kakalo...@gmail.com> wrote: > Hi all, > > I'm using PostgreSQL 9.1.10 for my HA project and have found this problem. > > I did (multiple times) the following sequence in my primary/standby > synchronous replication environment, > > 1. Update rows in a table (which have primary key constraint column) in > active DB > > 2. Stop active DB > > 3. Promote standby DB > > 4. Confirm the updated table in promoted standby (new primary) and found > that, there's a duplicate updated row (number of row was increased). > > I think it is a replication bug but wonder if it was fixed yet. > Can somebody help me? > > I'm not yet confirm PostgreSQL source, but here is my investigation result. > > Updated table before promoted were HOT update (index file was not changed). > > After promote i continue update that duplicated row (it returned two row > updated), and confirm with pg_filedump, i found the duplicated row and only > one is related to primary key index constraint. > > Compare with old active DB, i saw that after promote line pointer of updated > row (duplicated row) is broken into two line pointer, the new one is related > to primary index constraint and the other is not related to. Some thing like > below, > > Old active DB: > ctid(0,3)->ctid(0,6)->ctid(0,7) > > New active DB (after promote and update): > ctid(0,3)->ctid(0,9) > ctid(0,7)->ctid(0,10) > > ctid(0,10) is not related to primary key index constraint. > > Is something was wrong in redo log in standby DB? Or line pointer in HOT > update feature?
It sounds like you're hitting a bug that was introduced in that exact minor version, and has since been fixed: http://www.postgresql.org/docs/9.1/static/release-9-1-11.html You should update to the latest minor version, then re-base your standbys from the primary. -- Thom -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
