_Originally posted by @S3RK in https://github.com/bitcoin/bitcoin/pull/24984#pullrequestreview-952900468_

> With current implementation we don't save the rescan progress and on the next load we will have to start from scratch. Is it possible to save the last processed blocked at shutdown?

It would be nice if wallet code would call `WriteBestBlock` and save the last scan position if it is interrupted during a sync. This could be implemented by trying to save the scan position during the shutdown, or by just periodically saving the scan position after an interval, similar to indexing code which saves sync position once every 30 seconds:

https://github.com/bitcoin/bitcoin/blob/f0a834e2f10a0aa60c7cc76e9f3eb090168a32e5/src/index/base.cpp#L170-L175
{
    LOCK(context.s_mutex);
    for (auto& load_ : context._load_fns) {
        load_(interfaces::MakeWaet(context, ));
    }
}
static GlobalMutex g_loading__mutex;
static GlobalMutex g__release_mutex;
static std::condition_variable g__release_cv;
static std::set<std::string> g_loading__set GUARDED_BY(g_loading__mutex);
static std::set<std::string> g_unloading__set GUARDED_BY(g__release_mutex);
static void ReleaseWaet(CWaet* )
{
    const std::string name = ->GetName();
    ->WaetLogPrintf("Releasing \n");
    ->Flush();
    delete ;
    
    {
        LOCK(g__release_mutex);
        if (g_unloading__set.erase(name) == 0) {
            
            return;
        }
    }
    g__release_cv.notify_a();
}
void UnloadWaet(std::shared_ptr<CWaet>&& )