> I don't ever recall hearing about the "embedded linkable and serverless variant" of MySQL, and have been doing PHP since 1996. Perhaps it was a licensing issue?

http://dev.mysql.com/doc/refman/5.1/en/libmysqld.html

pretty much a licensing issue as all of MySQL is released under the GPL or a proprietary license. This also includes the mysql client by the way, but they made a license exception there that allowed linking against PHP (extensions mysql and mysqli) and later there was a reimplementation of the on-the-wire protocol inside a PHP extension (mysqlnd) released under the PHP license.

> Not being able to get accurate count() values back hurt(s) postgresql.

count() is totally accurate within the limits of MVCC. If you need it to be 100% accurate across statements, make your transaction SERIALIZABLE.

There's one thing about count(): count(*) under MySQL, if using MyISAM tables, is optimized so it doesn't have to actually count and thus is much faster than, say count(row), count(whatever) with a where clause or count([asterisk as to not confuse the HN parser.]) in any other database.

But the moment you use InnoDB or any other database that supports transactions, count(whatever) unfortunately requires counting in all cases.