> Vlad -
>
> Are you talking about CORE-595?

No, look at CORE-342, problem is not in sweep but more general.
For read-only databases Firebird incerements in-memory counter for
Next transaction when transaction starts. When this counter going to the
next (not-exists) TIP page we have a bugcheck 165.

To work around it recommend to reconnect to read-only database
after few thousand transactions. To be more precise - evaluate how many
transactions per TIP page your database support, let it be number T,
look at Next transaction in gstat -h output, let it be number N and :

X = T - (N mod T) - this is how many transactions you may start before
the bugcheck. So, you need to reconnect when new transaction number
is X -1 (or when N mod T == T - 1).

Regards,
Vlad

PS You may obtain number of transaction at client side using isc_transaction_info