Primary cache: per-component size statistics (#4890)

Before:

![image](https://github.com/rerun-io/rerun/assets/2910679/bec3e40a-529c-443d-9803-9581bfc977da)

After:

![image](https://github.com/rerun-io/rerun/assets/2910679/b1507279-7ca3-4c43-b47d-12b88864fdbc)


- Fix #4857
- DNR: requires #4856

### Checklist
* [x] I have read and agree to [Contributor
Guide](https://github.com/rerun-io/rerun/blob/main/CONTRIBUTING.md) and
the [Code of
Conduct](https://github.com/rerun-io/rerun/blob/main/CODE_OF_CONDUCT.md)
* [x] I've included a screenshot or gif (if applicable)
* [x] I have tested the web demo (if applicable):
* Using newly built examples:
[app.rerun.io](https://app.rerun.io/pr/4890/index.html)
* Using examples from latest `main` build:
[app.rerun.io](https://app.rerun.io/pr/4890/index.html?manifest_url=https://app.rerun.io/version/main/examples_manifest.json)
* Using full set of examples from `nightly` build:
[app.rerun.io](https://app.rerun.io/pr/4890/index.html?manifest_url=https://app.rerun.io/version/nightly/examples_manifest.json)
* [x] The PR title and labels are set such as to maximize their
usefulness for the next release's CHANGELOG

- [PR Build Summary](https://build.rerun.io/pr/4890)
- [Docs
preview](https://rerun.io/preview/06db01a65d711ec7ba802169845e3b79337a91af/docs)
<!--DOCS-PREVIEW-->
- [Examples
preview](https://rerun.io/preview/06db01a65d711ec7ba802169845e3b79337a91af/examples)
<!--EXAMPLES-PREVIEW-->
- [Recent benchmark results](https://build.rerun.io/graphs/crates.html)
- [Wasm size tracking](https://build.rerun.io/graphs/sizes.html)

crates/re_query_cache/src/cache.rs

@@ -756,7 +756,7 @@ impl CacheBucket {
             .or_insert_with(|| Box::new(FlatVecDeque::<C>::new()));
 
         // The `FlatVecDeque` will have to collect the data one way or another: do it ourselves
-        // instead, that way we can efficiently computes its size while we're at it.
+        // instead, that way we can efficiently compute its size while we're at it.
         let added: FlatVecDeque<C> = arch_view
             .iter_required_component::<C>()?
             .collect::<VecDeque<C>>()

crates/re_query_cache/src/cache_stats.rs

@@ -1,7 +1,7 @@
 use std::collections::BTreeMap;
 
 use re_log_types::{EntityPath, TimeRange, Timeline};
-use re_types_core::{ComponentName, SizeBytes as _};
+use re_types_core::{components::InstanceKey, ComponentName, Loggable as _, SizeBytes as _};
 
 use crate::{cache::CacheBucket, Caches, LatestAtCache, RangeCache};
 
@@ -62,6 +62,7 @@ impl CachedEntityStats {
 pub struct CachedComponentStats {
     pub total_rows: u64,
     pub total_instances: u64,
+    pub total_size_bytes: u64,
 }
 
 impl Caches {
@@ -75,11 +76,35 @@ impl Caches {
             per_component: &mut BTreeMap<ComponentName, CachedComponentStats>,
             bucket: &CacheBucket,
         ) {
-            for (component_name, data) in &bucket.components {
+            let CacheBucket {
+                data_times,
+                pov_instance_keys,
+                components,
+                total_size_bytes: _,
+            } = bucket;
+
+            {
+                let stats: &mut CachedComponentStats =
+                    per_component.entry("<timepoints>".into()).or_default();
+                stats.total_rows += data_times.len() as u64;
+                stats.total_instances += data_times.len() as u64;
+                stats.total_size_bytes += data_times.total_size_bytes();
+            }
+
+            {
+                let stats: &mut CachedComponentStats =
+                    per_component.entry(InstanceKey::name()).or_default();
+                stats.total_rows += pov_instance_keys.num_entries() as u64;
+                stats.total_instances += pov_instance_keys.num_values() as u64;
+                stats.total_size_bytes += pov_instance_keys.total_size_bytes();
+            }
+
+            for (component_name, data) in components {
                 let stats: &mut CachedComponentStats =
                     per_component.entry(*component_name).or_default();
                 stats.total_rows += data.dyn_num_entries() as u64;
                 stats.total_instances += data.dyn_num_values() as u64;
+                stats.total_size_bytes += data.dyn_total_size_bytes();
             }
         }
 

crates/re_query_cache/src/range.rs

@@ -180,9 +180,13 @@ macro_rules! impl_query_archetype_range {
             {
                 re_tracing::profile_scope!("fill");
 
+                // Grabbing the current time is quite costly on web.
+                #[cfg(not(target_arch = "wasm32"))]
                 let now = web_time::Instant::now();
 
+                #[cfg(not(target_arch = "wasm32"))]
                 let mut added_entries = 0u64;
+
                 let mut added_size_bytes = 0u64;
 
                 for arch_view in arch_views {
@@ -193,16 +197,23 @@ macro_rules! impl_query_archetype_range {
                     }
 
                     added_size_bytes += bucket.[<insert_pov$N _comp$M>]::<A, $($pov,)+ $($comp,)*>(data_time, &arch_view)?;
-                    added_entries += 1;
+
+                    #[cfg(not(target_arch = "wasm32"))]
+                    {
+                        added_entries += 1;
+                    }
                 }
 
-                let elapsed = now.elapsed();
-                ::re_log::trace!(
-                    archetype=%A::name(),
-                    added_size_bytes,
-                    "cached {added_entries} entries in {elapsed:?} ({:0.3} entries/s)",
-                    added_entries as f64 / elapsed.as_secs_f64()
-                );
+                #[cfg(not(target_arch = "wasm32"))]
+                {
+                    let elapsed = now.elapsed();
+                    ::re_log::trace!(
+                        archetype=%A::name(),
+                        added_size_bytes,
+                        "cached {added_entries} entries in {elapsed:?} ({:0.3} entries/s)",
+                        added_entries as f64 / elapsed.as_secs_f64()
+                    );
+                }
 
                 Ok(added_size_bytes)
             }

crates/re_viewer/src/ui/memory_panel.rs

@@ -425,17 +425,20 @@ impl MemoryPanel {
                             ui.label(egui::RichText::new("Component").underline());
                             ui.label(egui::RichText::new("Rows").underline());
                             ui.label(egui::RichText::new("Instances").underline());
+                            ui.label(egui::RichText::new("Size").underline());
                             ui.end_row();
 
                             for (component_name, stats) in per_component {
                                 let &CachedComponentStats {
                                     total_rows,
                                     total_instances,
+                                    total_size_bytes,
                                 } = stats;
 
                                 ui.label(component_name.to_string());
                                 ui.label(re_format::format_number(total_rows as _));
                                 ui.label(re_format::format_number(total_instances as _));
+                                ui.label(re_format::format_bytes(total_size_bytes as _));
                                 ui.end_row();
                             }
                         });