Verification errors - what do these mean?

ts678 · August 20, 2019, 2:19am

I don’t think I’ve seen any good explanation for this, but I’ll look at similar reports. There are several around.

Meanwhile, I’m cooking a theory, but I’ll hold it for the moment. What would help would be either you looking into your backup database with DB Browser for SQLite or similar (I can somewhat try to guide) or making a database bug report and posting a link to it. The DB doesn’t have your file data, but there’s some chance of pathname leakage because sanitization isn’t perfect. You can browse around yourself with the DB browser.

Also look around to see if there are any pathnames on other errors near this one. Some reports had them. Digging a pathname out of the DB might be pretty easy. Find “blocksetid: 26129” in File table. See its Path.
Possibly it’s something you don’t care much about, so possibly purging the file would remove the problem. Possibly also the File table doesn’t have that entry because transaction design backed it out or something.

github.com

duplicati/duplicati/blob/79d839546b238be79967bf8532267bfab2b08aa6/Duplicati/Library/Main/Database/LocalBackupDatabase.cs#L477-L490


if (c != 1)

{

    Logging.Log.WriteErrorMessage(LOGTAG, "CheckingErrorsForIssue1400", null, "Checking errors, related to #1400. Unexpected result count: {0}, expected {1}, hash: {2}, size: {3}, blocksetid: {4}, ix: {5}, fullhash: {6}, fullsize: {7}", c, 1, h, exsize, blocksetid, ix, filehash, size);

    using (var cmd = m_connection.CreateCommand(tr.Parent))

    {

        var bid = cmd.ExecuteScalarInt64(@"SELECT ""ID"" FROM ""Block"" WHERE ""Hash"" = ?", -1, h);

        if (bid == -1)

            throw new Exception(string.Format("Could not find any blocks with the given hash: {0}", h));

        foreach(var rd in cmd.ExecuteReaderEnumerable(@"SELECT ""Size"" FROM ""Block"" WHERE ""Hash"" = ?", h))

            Logging.Log.WriteErrorMessage(LOGTAG, "FoundIssue1400Error", null, "Found block with ID {0} and hash {1} and size {2}", bid, h, rd.ConvertValueToInt64(0, -1));

    }



    throw new Exception(string.Format("Unexpected result count: {0}, expected {1}, check log for more messages", c, 1));

}

is where the error is. It’s adding a blockset, which is the term for a file because it’s kept as a set of blocks. Some code seems to expect that all blocks except the last will be full blocks (102400 byte default), but it looks like a short block showed up. Blocks kept showing up until “fullsize: 1416392” was reached, but the short block partway through (it’s on the fifth block, i.e. “ix: 4” here) is raising an error and stopping a save. Probably the result is whatever file that is is short, but that actually might have been an earlier real length. The *Issue1400* is generally suspected of happening when files were changing at the time of the backup. Sometimes exclusions help (if the path can be found), or. –snapshot-policy can be used to keep view still.