A serious problem - mixed up profiles - 7.1

I had a member to email me stating:

Hi Team, when I Login, sometimes I get the page of "member1" . My username is
"member2". I invited a new friend called member3 and was writing a PM to
member4 when I got a message in my mail that the invitation was accepted and at
the same time noticed that on member4's page member3 was added at the same
time. All her friends are also my friends. There is definitely something wrong
here. Cheers ============ from member2

The site is at revision 17255.  Is this a bug with 7.1 B1? or a screwed up Dolphin installation?  Are the profiles screwed up? Am I up that proverbial creek without a paddle and will need to start over?

We exampled the database and the profile tables seem to be correct.  So we don't think it is a matter of a corrupted database.  Could their be any problems with session cookies that could cause this; we have two sites, one is a 7.0.9 site and the one showing the wrong profiles is 7.1.  The sites are on different domains, one on a shared host and the other is on a VPS, I have not looked at how Dolphin sets session cookies.  Or is it a bug in the 7.1 php scripts that displays profiles?  We have not seen this occur on the 7.0.9 site.

Caching has been known to cause strange problems on some servers as well. So i would trying shutting off caching options in dolphin and wait a while and see if the situation changes.

All caching or specific ones?

Start with the one that normally causes the most problems with is JS caching and JS compression. Then keep going if needed.

Or you can switch them all of to see if it solves it, then re-enable one and a time, wait and see what happens before re-enabling another one.

Trial and error basically. Because this is just a guess and i do not know which if any are causing it.

What does the DB cache do?  My guess is that it looks to see if the same query has been requested before and instead of executing it fetches a stored copy of the query results; or something.

I have noticed before that I turned off DB caching and still noticed that the pie chart showed DB statistics; just now I cleared the cache and it showed the pie chart as DB.  Clearing it again removed it.  If I turn off DB cache, it should not continue to show DB in the pie chart, correct?

Unknown. There are a few things i am still figuring out in the new version of of dolphin. Never really paid much attention to that pie chart.

Anyhow. The db cache keeps cached copies of database tables. Not individual queries. But not all tables are cached. Tables like sys_options are cached as that table is used frequently.

So if it is keeping a cache copy of the tables that handles profiles and that cache copy of the tables becomes corrupted for some reason, it could cause the mixed up profiles; possibly?

I think I will try turning it off as well if it will actually turn off.

I just noticed this setting in cache: "Enable cache for profiles information".  That sounds like a good candidate to turn off.

Possibly. But users profile data is not cached the same way. Profile data is cached individually on a per user basis. Each user has a separate profile cache in the cache folder.