On Tue, Aug 15, 2017 at 5:50 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
How did you shut down the existing installation? This'd be expected if you used "--mode immediate". Otherwise, I'd have thought those stats would still be there.
pg_ctl stop -m fast
That's how I've been doing it this whole while. My connotation is that postgres "fast" shutdown equates to oracle's immediate shutdown, but postgres "immediate" shutdown is akin to oracle's "shutdown abort". So fast should be a safe, consistent shutdown that doesn't require crash recovery after.
The optimizer's decisions are generally not based on the stats collector's info, but on the contents of pg_statistic. This observation doesn't prove anything about whether that was intact ... but I'd be really surprised if it wasn't.
Interesting, I'll have to read up on the difference here. I'm going to see if I can get another clone made up and test again, being sure to get the info before and after.
