On Mon, Oct 31, 2016 at 12:55 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
"Hunley, Douglas" <douglas.hunley@openscg.com> writes: > On Mon, Oct 31, 2016 at 10:38 AM, Tim Goodaire <tgoodaire@dyn.com> wrote: >> I have a question regarding the FSM corruption bug that is fixed in >> postgresql 9.5.5 (https://wiki.postgresql.org/wiki/Free_Space_Map_Problems). >> If I don't find any corruption on a master database, is it still possible >> that there is corruption on the standbys?
> It shouldn't be, iirc. FSMs are only ever created/updated by vacuum, which > doesn't run on a slave until it is promoted to a master.
The problem is that the WAL data can be wrong in these cases, and since the standbys only know what they were told in the WAL stream, their images will be wrong even if the master is valid.
I would have thought that the referenced page is clear enough about needing to check the standbys; do you think it isn't?
The page does clearly say that you need to check standby databases as well. The bit that I was unsure of is whether the absence of corruption on the master was evidence that this problem has not affected the standbys.
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Tim Goodaire Database Engineer Dyn, Inc tgoodaire@dyn.com M: 603-264-6642