bevyengine/bevy · error

too many entities

Error message

too many entities

What it means

Cold-path panic in FreshAllocator::on_overflow: the atomic next_entity_index reached MAX_ENTITIES (u32::MAX), so the allocator can never hand out another fresh index. This is an aggregate capacity exhaustion across all frees/allocations in this allocator, not a per-frame spike; the helper exists to keep the panic message and branch in one place.

Source

Thrown at crates/bevy_ecs/src/entity/remote_allocator.rs:770

}

impl FreshAllocator {
    /// This exists because it may possibly change depending on platform.
    /// Ex: We may want this to be smaller on 32 bit platforms at some point.
    const MAX_ENTITIES: u32 = u32::MAX;

    /// The total number of indices given out.
    #[inline]
    fn total_entity_indices(&self) -> u32 {
        self.next_entity_index.load(Ordering::Relaxed)
    }

    /// This just panics.
    /// It is included to help with branch prediction, and put the panic message in one spot.
    #[cold]
    #[inline]
    fn on_overflow() -> ! {
        panic!("too many entities")
    }

    /// Allocates a fresh [`EntityIndex`].
    /// This row has never been given out before.
    #[inline]
    fn alloc(&self) -> Entity {
        let index = self.next_entity_index.fetch_add(1, Ordering::Relaxed);
        if index == Self::MAX_ENTITIES {
            Self::on_overflow();
        }
        // SAFETY: We just checked that this was not max and we only added 1, so we can't have missed it.
        Entity::from_index(unsafe { EntityIndex::new(NonMaxU32::new_unchecked(index)) })
    }

    /// Allocates `count` [`EntityIndex`]s.
    /// These rows will be fresh.
    /// They have never been given out before.
    fn alloc_many(&self, count: u32) -> AllocUniqueEntityIndexIterator {

View on GitHub (pinned to 396ca72708)

Solutions

1. Free and recycle entity indices (despawn) instead of allocating indefinitely
2. Reduce entity churn: reuse pools for frequently spawned/despawned entities
3. For truly enormous workloads, shard work across multiple Worlds/allocators

When it happens

Trigger: Thrown at crates/bevy_ecs/src/entity/remote_allocator.rs:770 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of bevyengine/bevy@396ca72708 (2026-08-20). Data as JSON: /api/errors/d50e313e417584d2. Report an issue: GitHub.