Hi,
Using Bitcoin Core RPC client version v0.17.0.1-g1476554d3b1db5352c0de1de7524864d4bce3aac

I'm using bitcoin-cli loadwallet and unloadwallet commands. They both seem to work fine.
Unfortunately, memory is getting higher and higher, and no wallet can be loaded after 300 have been.
The problem may be related to BerkeleyDB rather than to Bitcoin Core itself. Fact is that lsof shows handles not cleared off after the unloadwallet command is issued. Files still handled are .walletlock, db.log and database/log.0000000001 .
When 300 different wallets have been loaded/unloaded, used RAM is over 8 GB, and bitcoind will finally become unstable and fail.

Any help would be appreciated.
Regards,
* Format a string to be used as option description in help messages
 *
 * @param option Option message (e.g. "-rpcuser=<user>")
 * @param message Option description (e.g. "Username for JSON-RPC connections")
 * @return the formatted string
 */
std::string HelpMessageOpt(const std::string& option, const std::string& message);
/**
 * Return the number of cores available on the current system.
 * @note This does count virtual cores, such as those provided by HyperThreading.
 */
int GetNumCores();
void RenameThread(const char* name);
/**
 * .. and a wrapper that just calls func once
 */
template <typename Callable> void TraceThread(const char* name,  Callable func)
{
    std::string s = strprintf("bitcoin-%s", name);
    RenameThread(s.c_str());
    try
    {
        LogPrintf("%s thread start\n", name);
        func();
        LogPrintf("%s thread exit\n", name);
    }
    catch (const boost::thread_interrupted&)
    {
        LogPrintf("%s thread interrupt\n", name);
        throw;