Let me just start off this post saying if you're not interested in InnoDB tablespace internals, then this might not be the post for you. :)

At any rate, whilst examining individual tablespace files (the .ibd file created when running with innodb_file_per_table option enabled) in their binary format, I noticed the initial page size for a individual tablespace did not appear to be 16k (as the default InnoDB page size is 16k).

Upon examining the actual binary data stored in the data file (just create a basic table and insert 10 rows), you can see data is written at the very beginning of the file (position 0).

One can also see data appearing at several (4) other places in this file.

I was trying to sync up what I was seeing with these InnoDB internals:

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