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,
{
    fs::path tmpFile = directory / fs::unique_path();
    FILE* file = fsbridge::fopen(tmpFile, "a");
    if (!file) return false;
    fclose(file);
    remove(tmpFile);
    return true;
}
/**
 * Interpret a string argument as a boolean.
 *
 * The definition of atoi() requires that non-numeric string values like "foo",
 * return 0. This means that if a user unintentionally supplies a non-integer
 * argument here, the return value is always false. This means that -foo=false
 * does what the user probably expects, but -foo=true is well defined but does
 * not do what they probably expected.
 *
 * The return value of atoi() is undefined when given input not representable as
 * an int. On most systems this means string value between "-2147483648" and
 * "2147483647" are well defined (this method will return true). Setting
 * -txindex=2147483648 on most systems, however, is probably undefined.
 *
 * For a more extensive discussion of this topic (and a wide range of opinions
 * on the Right Way to change this code), see PR12713.
 */
static bool InterpretBool(const std::string& strValue)