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| -rw-r--r-- | src/block/manager.rs | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/src/block/manager.rs b/src/block/manager.rs index ea984646..17b45935 100644 --- a/src/block/manager.rs +++ b/src/block/manager.rs @@ -222,6 +222,15 @@ impl BlockManager { // 1. Repair blocks from RC table. let mut next_start: Option<Hash> = None; loop { + // We have to do this complicated two-step process where we first read a bunch + // of hashes from the RC table, and then insert them in the to-resync queue, + // because of SQLite. Basically, as long as we have an iterator on a DB table, + // we can't do anything else on the DB. The naive approach (which we had previously) + // of just iterating on the RC table and inserting items one to one in the resync + // queue can't work here, it would just provoke a deadlock in the SQLite adapter code. + // This is mostly because the Rust bindings for SQLite assume a worst-case scenario + // where SQLite is not compiled in thread-safe mode, so we have to wrap everything + // in a mutex (see db/sqlite_adapter.rs). let mut batch_of_hashes = vec![]; let start_bound = match next_start.as_ref() { None => Bound::Unbounded, |