On Wednesday, January 9, 2013, Noah Misch wrote:
On Thu, Jan 10, 2013 at 02:45:36AM +0000, Simon Riggs wrote:
> On 8 January 2013 02:49, Noah Misch <noah@leadboat.com> wrote:
> > There is a bug in lazy_scan_heap()'s
> > bookkeeping for the xid to place in that WAL record. Each call to
> > heap_page_prune() simply overwrites vacrelstats->latestRemovedXid, but
> > lazy_scan_heap() expects it to only ever increase the value. I have a
> > attached a minimal fix to be backpatched. It has lazy_scan_heap() ignore
> > heap_page_prune()'s actions for the purpose of this conflict xid, because
> > heap_page_prune() emitted an XLOG_HEAP2_CLEAN record covering them.
>
> Interesting. Yes, bug, and my one of mine also.
>
> ISTM the right fix is fix to correctly initialize on pruneheap.c line 176
> prstate.latestRemovedXid = *latestRemovedXid;
> better to make it work than to just leave stuff hanging.
That works, too.
As bug fixes don't usually go through the commit-fest process, will someone be committing one of these two ideas for the back-branches? And to HEAD, in case the more invasive patch doesn't make it in?
I have a preliminary nit-pick on the big patch. It generates a compiler warning:
vacuumlazy.c: In function ‘lazy_scan_heap’:
vacuumlazy.c:445:9: warning: variable ‘prev_dead_count’ set but not used [-Wunused-but-set-variable]
Thanks,
Jeff