IPhoto shows new library despite it being 350gb!

Question

Having updated to Yosemite and the latest version of iPhoto I accessed my photos without problem for a few days from and an external portable RAID (set up in a mirrored array) on my MBP, then all of a sudden it said it needed to update thumbnails (it had recently done this successfully as I had bought a new Retina MBP). It crashed whilst doing this and then on the second or third attempt completed this to then say it was updating the cache. After several attempts it completed but now when it opens it shows a completely new empty library despite the fact that if you show the iPhoto package contents it clearly shows the old 350gb library but now with a new library it seems to have added in!
Having spent ages doing permissions, preferences, rebuild (in iPhoto and with iPhoto Library Manager) and all the usual stuff I phoned Apple and all they did was tell me to import the old masters from the old library into a new library which subsequently lost all my meta data. I have included a pic of what the iPhoto Library looks like. As you can see it looks as though a completely new library was created on 30th October.
Anything anyone could do to help would very much appreciated as I am not sure what to do now.
Thanks

Answer 1

While I remember, I have another experience to share. My backup initially wasn't the problem, I was able to restore the backup without any problem, it was the library upgrade process that consistently messed things up. It was only when the library was split into individual images that events seemed to be working out for the better.
Perhaps this is a question for the Time Machine discussions, but I was initially able to see the iPhoto library in Time Machine back for a number of months. During the iPhoto library update fiasco, this was suddenly and inexplicably reduced to about 30 days. Once I realized this I immediately turned Time Machine off so as not to have the oldest copy of the iPhoto library deleted. I then discovered that the oldest version of the iPhoto library in Time Machine was the only one large enough to be the entire image collection. Subsequent days backups were roughly a quarter of the size, these were backups made while I was trying to restore the original large backup.
I would ideally liked to have restored the library to my Mac hard drive, but at the time didn't have a hard drive large enough to accommodate the huge single file. Restoring the library from Time Machine to an external drive clearly didn't work, and maybe the root of my issue.
No matter how many times I try, I believe me, I've tried a number of times – every time I try to restore the largest library, the only one left in my Time Machine backup, the Finder preview tells me the file is about 350 GB, the restored file is a little more that 90 GB – sometimes smaller, and when connected to the iPhoto app, reveals all my photos, as they were, but only as thumbnails. Double click on a thumbnail and I get to see a large exclamation mark.
On the positive side, at least this library is in date order and contains only one copy of each image. I'm able to use this library to find images, then search for the image by name in the recovered images folder. It's not how I imagined my iPhoto experience would evolve, but I guess Yosemite is going to be the semi-analog period for my photo library, potentially until Apple realize that not every one of their customers is using a brand new machine and has more than 1,000 photos in their library.
Right now, my recovered images version of iPhoto feels like an unsorted pile of 80,000 images! I'm planning on visiting the Apple Genius bar again in the next couple of days to see if they can offer any assistance.
Thanks
Phil