Going to file this one as a bug as an inquiry to Sasha on the MySQL side of this hints at flakiness with pconnects in PHP 4.

We're running a PHP 4.0.1pl1/MySQL combination on three reasonable sized
dedicated servers (Dual PIII/1G RAM/Redhat/Raid 5). On the backend is the
database server, with two frontend web servers. MySQL works like a champ
unless I enable persistent connections, in which case I get a ton of the
following:

000701 19:23:20  Aborted connection 295169 to db: 'cashwars' user: 'root'
host: `216.205.94.xx' (Got an error reading communication packets)

MySQL quickly dies and I'm stuck doing a restart.  Switching back solves the problem. This
is with MySQL 3.23.18-alpha 

Running PHP 4.0.1pl1 as an Apache module, server is 2.2.13-0.13smp. 

./configure' '--disable-xml' '--without-gdb' '--disable-rpath' '--with-mysql' '--with-apxs=/usr/sbin/apxs' '--disable-debug' '--with-config-file-path=/etc/httpd/conf'

Running with connects solves the problem, but we do well over 250 requests/second, and the connection setup/teardown is no fun at that level. Hope to see this fixed or a workaround out soon...

August