Part 1 is with the medics and includes:
Height
weight
BP
heart rate
waist measurement
BMI (It's calculated as part of the part 1, regardless of how useless it is)
Framingham risk
Audiogram (hearing test)
vision test
Lifestyle questionnaire
Part 2 is with the doctor or PA where they assess your fitness for military service.
The part 2 is often not signed off the same day. Some people need to bring in additional documents regarding their health (especially for Class A members whose health care is done by their regular family doctor). Some people may be changing category (maybe their vision or hearing has gotten worse or improved?) and a second doctor has to sign off on it for concurrence. Same if you are on a TCAT and come off. The CF2088 (change in medical category and limitations) can take several weeks or months depending on this.
HOWEVER, make sure the MIR is aware the there is a contract pending on this medical category, so that once all the documents are received they can move it to the top of the pile and annoy the doctor until they sign it.
You only have one year from the date of your part 2 to submit any requested documents, otherwise your medical is null and void and has to be restarted.
If your file goes to DMedPol for review (usually for a PCAT) it can take 9 to 12 months before it comes back. Again, a pending contract can help expedite the process.