fix: size estimates (#4950)

* fix: `Tombstone::size` must include serialized predicate

* fix: `CachedPartition::size` must include `Arc` heap allocation

Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>

data_types/src/lib.rs

@@ -799,8 +799,7 @@ pub struct Tombstone {
 impl Tombstone {
     /// Estimate the memory consumption of this object and its contents
     pub fn size(&self) -> usize {
-        // No additional heap allocations
-        std::mem::size_of_val(self)
+        std::mem::size_of_val(self) + self.serialized_predicate.capacity()
     }
 }
 

querier/src/cache/partition.rs

@@ -136,6 +136,9 @@ struct CachedPartition {
 impl CachedPartition {
     /// RAM-bytes EXCLUDING `self`.
     fn size(&self) -> usize {
+        // Arc heap allocation
+        size_of_val(self.sort_key.as_ref()) +
+        // Arc content
         self.sort_key
             .as_ref()
             .as_ref()

querier/src/cache/tombstones.rs

@@ -275,8 +275,8 @@ mod tests {
 
         let cache = make_cache(&catalog);
 
-        let single_tombstone_size = 96;
-        let two_tombstone_size = 176;
+        let single_tombstone_size = 101;
+        let two_tombstone_size = 186;
         assert!(single_tombstone_size < two_tombstone_size);
 
         // Create tombstone 1