Error: Cannot find prevKey when creating shard_id #41
Description
Hi,
we seem to have a simple setup where we try to populate the DB with some keys and values as follows:
fn main() {
std::fs::remove_dir_all("qmdb_testdir").unwrap();
std::fs::create_dir_all("qmdb_testdir").unwrap();
let config = Config::from_dir("qmdb_testdir");
AdsCore::init_dir(&config);
let mut ads = AdsWrap::<SimpleTask>::new(&config);
let tasks_per_block = 10_000;
if tasks_per_block >= (1 << IN_BLOCK_IDX_BITS) {
panic!("tasks_per_block {} is too large", tasks_per_block);
}
let mut cset = ChangeSet::new();
let mut rng = rng();
let mut known_keys = HashSet::new();
for i in 0..1_000 {
let key = {
loop {
let key: Vec<u8> = (0..32).map(|_| rng.random()).collect(); // Generate a random 32-byte key
if !known_keys.contains(&key) {
known_keys.insert(key.clone());
break key;
}
}
};
known_keys.insert(key.clone());
let value: Vec<u8> = (0..32).map(|_| rng.random()).collect(); // Generate a random 32-byte value
let shard_id = byte0_to_shard_id(key[0]) as u8;
let mut key_array = [0u8; 32];
key_array.clone_from_slice(&key[..32]); // Copy the first 32 bytes into the array
cset.add_op(OP_CREATE, shard_id, &key_array, &key[..], &value[..], None);
}
cset.sort();
let task = SimpleTask::new(vec![cset]);
let task_list = vec![RwLock::new(Some(task))];
let height = 1;
let task_count = task_list.len() as i64;
println!("task count {}", task_count);
// task id's high 40 bits is block height and low 24 bits is task index
let last_task_id = (height << IN_BLOCK_IDX_BITS) | (task_count - 1);
println!("last task id {}", last_task_id);
ads.start_block(height, Arc::new(TasksManager::new(task_list, last_task_id)));
let shared_ads = ads.get_shared();
shared_ads.add_task((height << IN_BLOCK_IDX_BITS) | (task_count - 1));
ads.flush();
}However, we face the following error:
task count 1
last task id 16777216
FF key = [0, 108, 70, 149, 121, 15, 101, 231, 142, 0] file_pos = 360880
thread '<unnamed>' panicked at /home/useruser/.cargo/git/checkouts/qmdb-cd830a515878d17f/8def52e/qmdb/src/updater.rs:288:13:
Cannot find prevKey when creating shard_id=0 key=[0, 108, 198, 199, 203, 97, 109, 156, 191, 210, 198, 95, 229, 45, 47, 196, 143, 176, 226, 10, 122, 103, 17, 158, 83, 242, 218, 0, 169, 2, 21, 64]
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
FF key = [209, 152, 131, 169, 164, 169, 42, 223, 38, 0] file_pos = 362176
thread '<unnamed>' panicked at /home/useruser/.cargo/git/checkouts/qmdb-cd830a515878d17f/8def52e/qmdb/src/updater.rs:288:13:
Cannot find prevKey when creating shard_id=13 key=[209, 152, 241, 2, 85, 83, 240, 255, 61, 21, 92, 240, 207, 62, 174, 73, 253, 9, 86, 245, 45, 146, 221, 220, 35, 43, 90, 62, 119, 120, 152, 172]
...
What is going wrong here, especially when this is the first set of additions to DB with all distinct keys.