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#4 when i use , found Sanakirja crashes very frequently in both reading and writing

Opened by gcxfd on July 10, 2021
gcxfd on July 10, 2021

crash on read

thread '<unnamed>' panicked at 'RwLock reader count overflow', /Users/z/.cargo/registry/src/mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd/parking_lot-0.11.1/src/raw_rwlock.rs:698:3
0
thread 'note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
<unnamed>' panicked at 'RwLock reader count overflow', /Users/z/.cargo/registry/src/mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd/parking_lot-0.11.1/src/raw_rwlock.rs:698:30
thread 'thread '<unnamed><unnamed>' panicked at '' panicked at 'RwLock reader count overflowRwLock reader count overflow', ', /Users/z/.cargo/registry/src/mirrors.tuna.tsinghua.edu
.cn-df7c3c540f42cdbd/parking_lot-0.11.1/src/raw_rwlock.rs/Users/z/.cargo/registry/src/mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd/parking_lot-0.11.1/src/raw_rwlock.rs::698698::30
30

thread '<unnamed>' panicked at 'RwLock reader count overflow', /Users/z/.cargo/registry/src/mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd/parking_lot-0.11.1/src/raw_rwlock.rs:698:3
0
thread '<unnamed>' panicked at 'RwLock reader count overflow', /Users/z/.cargothread '<unnamed>' panicked at 'RwLock reader count overflow', /Users/z/.cargo/registry/src/mirrors.tu
na.tsinghua.edu.cn-df7c3c540f42cdbd/parking_lot-0.11.1/src/raw_rwlock.rs:698:30
0.00 sec/txt 101 ../txt/jianshu/df/94/df94be185870.txt
thread '<unnamed>' panicked at 'RwLock reader count overflow', /Users/z/.cargo/registry/src/mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd/parking_lot-0.11.1/src/raw_rwlock.rs:698:3
0
thread '<unnamed>' panicked at 'RwLock reader count overflow', /Users/z/.cargo/registry/src/mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd/parking_lot-0.11.1/src/raw_rwlock.rs:698:3
0
/registry/src/mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd/parking_lot-0.11.1/src/raw_rwlock.rs:698:30

crash on write


thread '<unnamed>' panicked at 'assertion failed: btree::del::del(self, &mut db, &f, None)?', /Users/z/.cargo/registry/src/mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd/sanakirja-1
.2.5/src/environment/muttxn.rs:405:9
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
0.00 sec/txt 101 ../txt/jianshu/df/94/df94be185870.txt
thread '<unnamed>' panicked at 'assertion failed: btree::del::del(self, &mut db, &f, None)?', /Users/z/.cargo/registry/src/mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd/sanakirja-1
.2.5/src/environment/muttxn.rs:405:9
thread '<unnamed>' panicked at 'assertion failed: btree::del::del(self, &mut db, &f, None)?', /Users/z/.cargo/registry/src/mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd/sanakirja-1
.2.5/src/environment/muttxn.rs:405:9
thread '<unnamed>' panicked at 'assertion failed: btree::del::del(self, &mut db, &f, None)?', /Users/z/.cargo/registry/src/mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd/sanakirja-1
.2.5/src/environment/muttxn.rs:405:9
0.00 sec/txt 201 ../txt/jianshu/1f/a1/1fa1a1d0d077.txt
thread '<unnamed>' panicked at 'assertion failed: btree::del::del(self, &mut db, &f, None)?', /Users/z/.cargo/registry/src/mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd/sanakirja-1
.2.5/src/environment/muttxn.rs:405:9
thread '<unnamed>' panicked at 'assertion failed: btree::del::del(self, &mut db, &f, None)?', /Users/z/.cargo/registry/src/mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd/sanakirja-1
.2.5/src/environment/muttxn.rs:405:9
thread '<unnamed>' panicked at 'assertion failed: btree::del::del(self, &mut db, &f, None)?', /Users/z/.cargo/registry/src/mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd/sanakirja-1
.2.5/src/environment/muttxn.rs:405:9
0.00 sec/txt 301 ../txt/jianshu/55/0d/550d7016a044.txt
thread '<unnamed>' panicked at 'assertion failed: btree::del::del(self, &mut db, &f, None)?', /Users/z/.cargo/registry/src/mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd/sanakirja-1
.2.5/src/environment/muttxn.rs:405:9
thread '<unnamed>' panicked at 'assertion failed: btree::del::del(self, &mut db, &f, None)?', /Users/z/.cargo/registry/src/mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd/sanakirja-1
.2.5/src/environment/muttxn.rs:405:9
pmeunier on July 10, 2021

For the reading, the panic isn’t happening inside Sanakirja, but inside Parking_lot.

This sounds like you’re opening a very large number of readers at the same time, and keep them all open. I’d be curious to see your code for that, and know more about the exact scenario: how long do you have to wait before you see these crashes?

For the writing, this sounds like a bug, although I don’t quite know where it comes from. If you can, I’d be interested to see your database just after this happens (having it just before would be great too), or at least have some way to reproduce.

If you can run with RUST_LOG="sanakirja=debug" RUST_BACKTRACE=1, it would also be useful to see the output of that.

gcxfd on July 10, 2021

Clone the project, put thousands of .txt files under ./txt, and then run ./train/train.sh You can see the error recurring.

Currently I am busy writing another project, and I will give you a minimal version of the code to reproduce the bug when I have time.

pmeunier on July 10, 2021

Thanks! I’m seeing unexpected things when I look at your sdb, such as:

    let tx = &self.0;
    match tx.root_db::<K, V, P>(id) {
      None => {
        let mut w = Env::mut_txn_begin(tx.env_borrow()).unwrap();
        let tree = create_db_::<_, K, V, P>(&mut w).unwrap();
        w.set_root(id, tree.db);
        w.commit().unwrap();
        tree
      }
      Some(tree) => tree,
    }

This is very strange, a Db can’t exist outside of a transaction. You can think of a Db as a pointer to a small part of a large block of allocated memory (the Txn). Once the Txn is gone, it is as if the memory didn’t exist anymore.

Unfortunately, the Rust typesystem is a bit weak to express all the things we want to do with Db, such as storing a Db inside another Db.

I can definitely try to have a closer look at sdb, because I think you’re seeing a standard case of corruption here.

gcxfd on July 10, 2021

I upgrade sdb, now use tx.root_db::<K, V, P>(id).unwrap() in ReadTx and create db when program init ( https://github.com/rmw-link/sdb/blob/daddcc5ae2802c6d41ebdd5f0772607d77e0d2b6/sdb/src/lib.rs#L374 ).

Now use train program ( https://github.com/gcxfd/rmw-utf8/blob/3d05df8a05e701e78ceb8bd0f1f0de0e07dd21ca/train/src/main.rs#L193 )

somethings error 


0.00 sec/txt 1 ../txt/jianshu/61/b4/61b4fc52d20d.txt
0.00 sec/txt 101 ../txt/jianshu/df/94/df94be185870.txt
0.00 sec/txt 201 ../txt/jianshu/1f/a1/1fa1a1d0d077.txt
thread '<unnamed>' panicked at 'assertion failed: btree::del::del(self, &mut db, &f, None)?', /Users/z/.cargo/registry/src/mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd/sanakirja-1.2.5/src/environment/muttxn.rs:405:9
stack backtrace:
   0: rust_begin_unwind
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/std/src/panicking.rs:515:5
   1: core::panicking::panic_fmt
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/core/src/panicking.rs:92:14
   2: core::panicking::panic
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/core/src/panicking.rs:50:5
   3: <sanakirja::environment::muttxn::MutTxn<E,T> as sanakirja_core::AllocPage>::alloc_page
   4: sanakirja_core::btree::page::put::put
   5: sanakirja_core::btree::put::put
   6: sdb::dbpage::DbPage<K,V,P,RK,RV>::put
   7: <rayon::iter::map_with::MapWithFolder<C,U,F> as rayon::iter::plumbing::Folder<T>>::consume
   8: <rayon::iter::par_bridge::IterParallelProducer<Iter> as rayon::iter::plumbing::UnindexedProducer>::fold_with
   9: rayon::iter::plumbing::bridge_unindexed_producer_consumer
  10: <rayon_core::job::StackJob<L,F,R> as rayon_core::job::Job>::execute
  11: rayon_core::registry::WorkerThread::wait_until_cold
  12: rayon_core::registry::ThreadBuilder::run
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
0.00 sec/txt 301 ../txt/jianshu/55/0d/550d7016a044.txt

somethings error 


0.00 sec/txt 1 ../txt/jianshu/61/b4/61b4fc52d20d.txt
0.00 sec/txt 101 ../txt/jianshu/df/94/df94be185870.txt
thread '<unnamed>' panicked at 'assertion failed: btree::del::del(self, &mut db, &f, None)?', /Users/z/.cargo/registry/src/mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd/sanakirja-1.2.5/src/environment/muttxn.rs:405:9
stack backtrace:
   0: rust_begin_unwind
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/std/src/panicking.rs:515:5
   1: core::panicking::panic_fmt
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/core/src/panicking.rs:92:14
   2: core::panicking::panic
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/core/src/panicking.rs:50:5
   3: <sanakirja::environment::muttxn::MutTxn<E,T> as sanakirja_core::AllocPage>::alloc_page
   4: sanakirja_core::btree::page::put::put
   5: sanakirja_core::btree::put::put
   6: sdb::dbpage::DbPage<K,V,P,RK,RV>::put
   7: <rayon::iter::map_with::MapWithFolder<C,U,F> as rayon::iter::plumbing::Folder<T>>::consume
   8: <rayon::iter::par_bridge::IterParallelProducer<Iter> as rayon::iter::plumbing::UnindexedProducer>::fold_with
   9: rayon::iter::plumbing::bridge_unindexed_producer_consumer
  10: rayon_core::registry::in_worker
  11: rayon::iter::plumbing::bridge_unindexed_producer_consumer
  12: rayon_core::registry::in_worker
  13: rayon::iter::plumbing::bridge_unindexed_producer_consumer
  14: rayon_core::registry::in_worker
  15: rayon::iter::plumbing::bridge_unindexed_producer_consumer
  16: rayon_core::registry::in_worker
  17: rayon::iter::plumbing::bridge_unindexed_producer_consumer
  18: rayon_core::registry::in_worker
  19: rayon::iter::plumbing::bridge_unindexed_producer_consumer
  20: rayon_core::join::join_context::{{closure}}
  21: rayon_core::unwind::halt_unwinding
  22: <rayon_core::job::StackJob<L,F,R> as rayon_core::job::Job>::execute
  23: rayon_core::registry::WorkerThread::wait_until_cold
  24: rayon_core::registry::ThreadBuilder::run
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
thread '<unnamed>' panicked at 'assertion failed: btree::del::del(self, &mut db, &f, None)?', /Users/z/.cargo/registry/src/mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd/sanakirja-1.2.5/src/environment/muttxn.rs:405:9
stack backtrace:
   0: rust_begin_unwind
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/std/src/panicking.rs:515:5
   1: core::panicking::panic_fmt
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/core/src/panicking.rs:92:14
   2: core::panicking::panic
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/core/src/panicking.rs:50:5
   3: <sanakirja::environment::muttxn::MutTxn<E,T> as sanakirja_core::AllocPage>::alloc_page
   4: sanakirja_core::btree::page::put::put
   5: sanakirja_core::btree::put::put
   6: sdb::dbpage::DbPage<K,V,P,RK,RV>::put
   7: <rayon::iter::map_with::MapWithFolder<C,U,F> as rayon::iter::plumbing::Folder<T>>::consume
   8: <rayon::iter::par_bridge::IterParallelProducer<Iter> as rayon::iter::plumbing::UnindexedProducer>::fold_with
   9: rayon::iter::plumbing::bridge_unindexed_producer_consumer
  10: rayon_core::registry::in_worker
  11: rayon::iter::plumbing::bridge_unindexed_producer_consumer
  12: <rayon_core::job::StackJob<L,F,R> as rayon_core::job::Job>::execute
  13: rayon_core::registry::WorkerThread::wait_until_cold
  14: rayon_core::registry::ThreadBuilder::run
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
thread '<unnamed>' panicked at 'assertion failed: btree::del::del(self, &mut db, &f, None)?', /Users/z/.cargo/registry/src/mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd/sanakirja-1.2.5/src/environment/muttxn.rs:405:9
stack backtrace:
   0: rust_begin_unwind
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/std/src/panicking.rs:515:5
   1: core::panicking::panic_fmt
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/core/src/panicking.rs:92:14
   2: core::panicking::panic
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/core/src/panicking.rs:50:5
   3: <sanakirja::environment::muttxn::MutTxn<E,T> as sanakirja_core::AllocPage>::alloc_page
   4: sanakirja_core::btree::page::put::put
   5: sanakirja_core::btree::put::put
   6: sdb::dbpage::DbPage<K,V,P,RK,RV>::put
   7: <rayon::iter::map_with::MapWithFolder<C,U,F> as rayon::iter::plumbing::Folder<T>>::consume
   8: <rayon::iter::par_bridge::IterParallelProducer<Iter> as rayon::iter::plumbing::UnindexedProducer>::fold_with
   9: rayon::iter::plumbing::bridge_unindexed_producer_consumer
  10: <rayon_core::job::StackJob<L,F,R> as rayon_core::job::Job>::execute
  11: rayon_core::registry::WorkerThread::wait_until_cold
  12: rayon_core::registry::ThreadBuilder::run
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
thread '<unnamed>' panicked at 'assertion failed: btree::del::del(self, &mut db, &f, None)?', /Users/z/.cargo/registry/src/mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd/sanakirja-1.2.5/src/environment/muttxn.rs:405:9
stack backtrace:
   0: rust_begin_unwind
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/std/src/panicking.rs:515:5
   1: core::panicking::panic_fmt
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/core/src/panicking.rs:92:14
   2: core::panicking::panic
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/core/src/panicking.rs:50:5
   3: <sanakirja::environment::muttxn::MutTxn<E,T> as sanakirja_core::AllocPage>::alloc_page
   4: sanakirja_core::btree::page::put::put
   5: sanakirja_core::btree::put::put
   6: sdb::dbpage::DbPage<K,V,P,RK,RV>::put
   7: <rayon::iter::map_with::MapWithFolder<C,U,F> as rayon::iter::plumbing::Folder<T>>::consume
   8: <rayon::iter::par_bridge::IterParallelProducer<Iter> as rayon::iter::plumbing::UnindexedProducer>::fold_with
   9: rayon::iter::plumbing::bridge_unindexed_producer_consumer
  10: <rayon_core::job::StackJob<L,F,R> as rayon_core::job::Job>::execute
  11: rayon_core::registry::WorkerThread::wait_until_cold
  12: rayon_core::registry::ThreadBuilder::run
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
thread '<unnamed>' panicked at 'assertion failed: btree::del::del(self, &mut db, &f, None)?', /Users/z/.cargo/registry/src/mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd/sanakirja-1.2.5/src/environment/muttxn.rs:405:9
stack backtrace:
   0: rust_begin_unwind
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/std/src/panicking.rs:515:5
   1: core::panicking::panic_fmt
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/core/src/panicking.rs:92:14
   2: core::panicking::panic
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/core/src/panicking.rs:50:5
   3: <sanakirja::environment::muttxn::MutTxn<E,T> as sanakirja_core::AllocPage>::alloc_page
   4: sanakirja_core::btree::page::put::put
   5: sanakirja_core::btree::put::put
   6: sdb::dbpage::DbPage<K,V,P,RK,RV>::put
   7: <rayon::iter::map_with::MapWithFolder<C,U,F> as rayon::iter::plumbing::Folder<T>>::consume
   8: <rayon::iter::par_bridge::IterParallelProducer<Iter> as rayon::iter::plumbing::UnindexedProducer>::fold_with
   9: rayon::iter::plumbing::bridge_unindexed_producer_consumer
  10: rayon_core::registry::in_worker
  11: rayon::iter::plumbing::bridge_unindexed_producer_consumer
  12: <rayon_core::job::StackJob<L,F,R> as rayon_core::job::Job>::execute
  13: rayon_core::registry::WorkerThread::wait_until_cold
  14: rayon_core::registry::ThreadBuilder::run
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
thread '<unnamed>' panicked at 'assertion failed: btree::del::del(self, &mut db, &f, None)?', /Users/z/.cargo/registry/src/mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd/sanakirja-1.2.5/src/environment/muttxn.rs:405:9
stack backtrace:
   0: rust_begin_unwind
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/std/src/panicking.rs:515:5
   1: core::panicking::panic_fmt
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/core/src/panicking.rs:92:14
   2: core::panicking::panic
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/core/src/panicking.rs:50:5
   3: <sanakirja::environment::muttxn::MutTxn<E,T> as sanakirja_core::AllocPage>::alloc_page
   4: sanakirja_core::btree::page::put::put
   5: sanakirja_core::btree::put::put
   6: sdb::dbpage::DbPage<K,V,P,RK,RV>::put
   7: <rayon::iter::map_with::MapWithFolder<C,U,F> as rayon::iter::plumbing::Folder<T>>::consume
   8: <rayon::iter::par_bridge::IterParallelProducer<Iter> as rayon::iter::plumbing::UnindexedProducer>::fold_with
   9: rayon::iter::plumbing::bridge_unindexed_producer_consumer
  10: <rayon_core::job::StackJob<L,F,R> as rayon_core::job::Job>::execute
  11: rayon_core::registry::WorkerThread::wait_until_cold
  12: rayon_core::registry::ThreadBuilder::run
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
thread '<unnamed>' panicked at 'assertion failed: btree::del::del(self, &mut db, &f, None)?', /Users/z/.cargo/registry/src/mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd/sanakirja-1.2.5/src/environment/muttxn.rs:405:9
stack backtrace:
   0: rust_begin_unwind
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/std/src/panicking.rs:515:5
   1: core::panicking::panic_fmt
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/core/src/panicking.rs:92:14
   2: core::panicking::panic
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/core/src/panicking.rs:50:5
   3: <sanakirja::environment::muttxn::MutTxn<E,T> as sanakirja_core::AllocPage>::alloc_page
   4: sanakirja_core::btree::page::put::put
   5: sanakirja_core::btree::put::put
   6: sdb::dbpage::DbPage<K,V,P,RK,RV>::put
   7: <rayon::iter::map_with::MapWithFolder<C,U,F> as rayon::iter::plumbing::Folder<T>>::consume
   8: <rayon::iter::par_bridge::IterParallelProducer<Iter> as rayon::iter::plumbing::UnindexedProducer>::fold_with
   9: rayon::iter::plumbing::bridge_unindexed_producer_consumer
  10: <rayon_core::job::StackJob<L,F,R> as rayon_core::job::Job>::execute
  11: rayon_core::registry::WorkerThread::wait_until_cold
  12: rayon_core::registry::ThreadBuilder::run
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
thread '<unnamed>' panicked at 'assertion failed: btree::del::del(self, &mut db, &f, None)?', /Users/z/.cargo/registry/src/mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd/sanakirja-1.2.5/src/environment/muttxn.rs:405:9
stack backtrace:
   0: rust_begin_unwind
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/std/src/panicking.rs:515:5
   1: core::panicking::panic_fmt
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/core/src/panicking.rs:92:14
   2: core::panicking::panic
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/core/src/panicking.rs:50:5
   3: <sanakirja::environment::muttxn::MutTxn<E,T> as sanakirja_core::AllocPage>::alloc_page
   4: sanakirja_core::btree::page::put::put
   5: sanakirja_core::btree::put::put
   6: sdb::dbpage::DbPage<K,V,P,RK,RV>::put
   7: <rayon::iter::map_with::MapWithFolder<C,U,F> as rayon::iter::plumbing::Folder<T>>::consume
   8: <rayon::iter::par_bridge::IterParallelProducer<Iter> as rayon::iter::plumbing::UnindexedProducer>::fold_with
   9: rayon::iter::plumbing::bridge_unindexed_producer_consumer
  10: <rayon_core::job::StackJob<L,F,R> as rayon_core::job::Job>::execute
  11: rayon_core::registry::WorkerThread::wait_until_cold
  12: rayon_core::registry::ThreadBuilder::run
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
thread '<unnamed>' panicked at 'assertion failed: btree::del::del(self, &mut db, &f, None)?', /Users/z/.cargo/registry/src/mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd/sanakirja-1.2.5/src/environment/muttxn.rs:405:9
stack backtrace:
   0: rust_begin_unwind
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/std/src/panicking.rs:515:5
   1: core::panicking::panic_fmt
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/core/src/panicking.rs:92:14
   2: core::panicking::panic
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/core/src/panicking.rs:50:5
   3: <sanakirja::environment::muttxn::MutTxn<E,T> as sanakirja_core::AllocPage>::alloc_page
   4: sanakirja_core::btree::page::put::put
   5: sanakirja_core::btree::put::put
   6: sdb::dbpage::DbPage<K,V,P,RK,RV>::put
   7: <rayon::iter::map_with::MapWithFolder<C,U,F> as rayon::iter::plumbing::Folder<T>>::consume
   8: <rayon::iter::par_bridge::IterParallelProducer<Iter> as rayon::iter::plumbing::UnindexedProducer>::fold_with
   9: rayon::iter::plumbing::bridge_unindexed_producer_consumer
  10: <rayon_core::job::StackJob<L,F,R> as rayon_core::job::Job>::execute
  11: rayon_core::registry::WorkerThread::wait_until_cold
  12: rayon_core::join::join_recover_from_panic
  13: rayon_core::registry::in_worker
  14: rayon::iter::plumbing::bridge_unindexed_producer_consumer
  15: rayon_core::registry::in_worker
  16: rayon::iter::plumbing::bridge_unindexed_producer_consumer
  17: rayon_core::registry::in_worker
  18: rayon::iter::plumbing::bridge_unindexed_producer_consumer
  19: rayon_core::registry::in_worker
  20: rayon::iter::plumbing::bridge_unindexed_producer_consumer
  21: rayon_core::registry::in_worker
  22: rayon::iter::plumbing::bridge_unindexed_producer_consumer
  23: rayon_core::join::join_context::{{closure}}
  24: rayon_core::unwind::halt_unwinding
  25: <rayon_core::job::StackJob<L,F,R> as rayon_core::job::Job>::execute
  26: rayon_core::registry::WorkerThread::wait_until_cold
  27: rayon_core::registry::ThreadBuilder::run
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
thread 'main' panicked at 'assertion failed: btree::del::del(self, &mut db, &f, None)?', /Users/z/.cargo/registry/src/mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd/sanakirja-1.2.5/src/environment/muttxn.rs:405:9
stack backtrace:
   0: rust_begin_unwind
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/std/src/panicking.rs:515:5
   1: core::panicking::panic_fmt
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/core/src/panicking.rs:92:14
   2: core::panicking::panic
             at /rustc/6d820866a27b1949e237be79b9c8c0145fe728b7/library/core/src/panicking.rs:50:5
   3: <sanakirja::environment::muttxn::MutTxn<E,T> as sanakirja_core::AllocPage>::alloc_page
   4: sanakirja_core::btree::page_unsized::put::put
   5: sanakirja_core::btree::put::put
   6: sdb::dbpage::DbPage<K,V,P,RK,RV>::upsert
   7: train::word_huffman
   8: train::main
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
gcxfd on July 10, 2021

I added the train txt into git repo , so just git clone https://github.com/gcxfd/rmw-utf8.git and 

cd train
rm -rf cache && ./train.sh

can see error