I came in this morning and noticed this warning sitting in my inbox quite a few times...
WARNING: PD_ALL_VISIBLE flag was incorrectly set in relation "table_2010q1" page 471118 WARNING: PD_ALL_VISIBLE flag was incorrectly set in relation "table_2010q1" page 471119 WARNING: PD_ALL_VISIBLE flag was incorrectly set in relation "table_2010q1" page 471120 ....
and I'm wondering how worked up I should be getting.
I'm trying to do due diligence on my side and am digging through archives, but just in case it's a cause for greater alarm than I think it is I'm going to throw this out there and see what those more experienced that I say.
Postgres version 8.4.1, redhat 5.3.
The table in question is about 6 million rows, a single partition in a larger set. A relatively heavy load (mass insert followed by a mass update) takes place each morning, during the time period where I was seeing this error. Auto-vacuum apparently kicked off at this time as well (auto-analyze is showing last-run at 4:27 AM, auto-vacuum at 8:48). The first warning kicked off at 4:55.
My assumption here is that the load from the inserts/updates was interfering with auto-vacuum in some way, and resulted in the above warnings. Is this a reasonable assumption at all? I'm under the impression that auto-vacuum will kill itself if it notices that it's hurting performance, but I wouldn't think it should throw all of these warnings...does it indicate poor auto-vacuum configuration? I admit that said configuration is an area that I've been meaning to look into more (upgraded from 8.1 where we didn't use auto-vacuum), but hasn't ended up on the top of the priorities list yet.
