On Fri, Apr 13, 2012 at 5:33 PM, Robert Haas <robertmh...@gmail.com> wrote: > Currently, we have a problem with index-only scans in Hot Standby > mode: the xmin horizon on the standby might lag the master, and thus > an index-only scan might mistakenly conclude that no heap fetch is > needed when in fact it is. I suggested that we handle this by > suppressing generation of index-only scan plans in Hot Standby mode, > but Simon, Noah, and Dimitri were arguing that we should instead do > the following, which is now on the open items list: > > * Make XLOG_HEAP2_VISIBLE records generate recovery snapshot conflicts > so that IndexOnlyScans work on Hot Standby ... <snip> very long email </snip>
Luckily its much simpler than all of that suggests. It'll take a few hours for me to write a short reply but its Sunday today, so that will happen later. -- 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
