On 30 January 2014 17:27, Robert Haas <robertmh...@gmail.com> wrote: > On Wed, Jan 29, 2014 at 3:11 PM, Simon Riggs <si...@2ndquadrant.com> wrote: >> On 14 January 2014 08:38, Christian Kruse <christ...@2ndquadrant.com> wrote: >>> Hi, >>> On 13/01/14 20:06, Heikki Linnakangas wrote: >>>> On 12/17/2013 04:58 PM, Christian Kruse wrote: >>>> >attached you will find a patch for showing the current transaction id >>>> >(xid) and the xmin of a backend in pg_stat_activty and the xmin in >>>> >pg_stat_replication. >>>> >>>> Docs. >>> >>> Thanks, update with updated docs is attached. >> >> Looks simple enough and useful for working out which people are >> holding up CONCURRENT activities. >> >> I've not been involved with this patch, so any objections to me doing >> final review and commit? > > Nope, but I think this patch is broken. It looks to me like it's > conflating the process offset in the BackendStatus array with its > backendId, which does not seem like a good idea even if it happens to > work at present. And the way BackendIdGetProc() is used looks unsafe, > too: the contents might no longer be valid by the time we read them. > I suspect we should have a new accessor function that takes a backend > ID and copies the xid and xmin to pointers provided by the client > while holding the lock. I also note that the docs seem to need some > copy-editing: > > + <entry>The current <xref linked="ddl-system-columns">xmin > value.</xref></entry>
Thanks, saved me the trouble of a detailed review... good catches. -- 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
