> The protocol reflects the API. Do you have any suggestions for reducing
> the number of round trips?

Very often appliactions repeat this steps

isc_alloc_statement2
isc_prepare
isc_dsql_sql_info (isc_info_sql_stmt_type)
isc_dsql_sql_info (isc_info_sql_get_plan)
isc_dsql_execute2
isc_dsql_set_cursor_name
isc_dsql_sql_info (isc_info_sql_records)
...

First step may be to merge isc_xxx_info calls into corresponding xxx calls,
for example :

[isc_alloc_statement2 + ] isc_prepare + isc_dsql_sql_info

isc_dsql_execute2 + isc_dsql_sql_info [+ isc_dsql_set_cursor_name]

isc_start_transaction + isc_transaction_info

Regards,
Vlad