I'm not talking about my load, and I've never mentioned having problems with my server. I'm referring to common knowledge that MySQL runs into scalability problems.
You never did tell me how you managed to get 1000 concurrent connections on MySQL.
Here's two quotes from the afore mentioned PHPBuilder article above:
The most interesting thing about my test results was to see how much of a load Postgres could withstand before giving any errors. In fact, Postgres seemed to scale 3 times higher than MySQL before giving any errors at all. MySQL begins collapsing at about 40-50 concurrent connections, whereas Postgres handily scaled to 120 before balking. My guess is, that Postgres could have gone far past 120 connections with enough memory and CPU.
Another interesting point was that MySQL crumbles faster in the "10% insert" test described above. Research reveals that MySQL locks the entire table when an insert occurs, while Postgres has a pretty nifty "better than row-level locking" feature. This difference quickly causes MySQL to pile up concurrent connections and thus collapse. The same is true if you are doing a large select out of a database while another process is inserting into that table. Postgres is completely unfazed, while MySQL piles up connections until it falls apart like a house of cards.
Now, it's important to point out that this article was done 2 years ago and since then PostgreSQL and MySQL have both released new versions which do indeed scale better. HOWEVER, MySQL (talk to anybody with a LARGE web site that runs MySQL) does NOT scale well still. That's simply a fact of life, due to the way it works. And I'm not talking about CPU load, I'm talking about how long it takes to run a query, and what happens when your queries start building up and the daemon crashes. I've seen no proof that MySQL will scale beyond a fairly low - medium number of connections (50 - 100) all performing mixed SELECT and INSERT/UPDATE queries. I have however, see PLENTY of information that outright states that MySQL cannot hold its weight in an enterprise/large user base environment. Now PLEASE, show us some hard data before you continue hackie.