[ic] rpc mode db sessions broken in 4.9.8?

[Jack Cushman]

Hi, folks.

We're having trouble getting mysql database sessions to work under IC
4.9.8/4.9.9 in rpc mode. The installation works fine in rpc mode with
sessions on disk, or in high mode with sessions in the session table.
When we try both at once, this comes up during the session read:

> Died in server spawn: DBD::mysql::st execute failed: MySQL server has
gone away at /usr/lib/interchange/lib/Vend/Table/DBI.pm line 1793.
> Server spawn error: Can't use an undefined value as an ARRAY reference
at /usr/lib/interchange/lib/Vend/Util.pm line 1070.

The error comes up only on the second page view -- perhaps it's like
that 4.9.9 rpc fix, where certain settings don't make it into the new
thread spawn. The mysql server is very much available, and even ends up
with entries in the session table, from the threads that work. Debugging
at line 1793 indicates it was trying to run "SELECT * FROM session", and
that the dbi reference is active but cannot connect to DB.

Versions and such:

* mysql  Ver 12.22 Distrib 4.0.16, for pc-linux (i686) -- running on a
separate machine
* Interchange 4.9.8 or 4.9.9 (Redhat 9 package) (we tried both)
* Perl v5.6.1

This feels like an IC core bug, but I've been wrong before. Let me know
if there's anything else I should try.

Thanks,
Jack Cushman