Thanks Thomas,

We are explicitly starting and committing our own transactions rather than
relying on any auto-commit behaviour.

We are running Classic (sorry I should have told you that already).

I'll get our devs to checkout the MON$ tables and see what additional info
can be gleaned from them.

A current gstat -h output is this below, we experienced the slowdown a
little while ago tonight.

Database header page information:
Flags 0
Checksum 12345
Generation 2240486
Page size 8192
ODS version 11.2
Oldest transaction 1616642
Oldest active 2143185
Oldest snapshot 2143185
Next transaction 2168081
Bumped transaction 1
Sequence number 0
Next attachment ID 72398
Implementation ID 26
Shadow count 0
Page buffers 0
Next header page 0
Database dialect 3
Creation date Mar 26, 2016 10:35:08
Attributes force write

Variable header data:
Sweep interval: 0
*END*

We have a scheduled task that runs out of hours to handle the sweep process.

Thanks,

Neil Pickles