catalog: optimize adding all entries from a catalog

Previously, when copying from different catalog objects incurred
unnecessary overhead by copying values. To address this, this patch will
move references over between them.

Before this and the previous patch applied:
BenchmarkORMQueries/asyncpg_type  13252306945 ns/op 5442736128 B/op 29586155 allocs/op
After this patch:
BenchmarkORMQueries/asyncpg_types 12399752839 ns/op 4602288096 B/op 27474078 allocs/op

Informs: #124750

Release note: None

pkg/sql/catalog/nstree/catalog_mutable.go

@@ -50,14 +50,26 @@ func (mc *MutableCatalog) ensureForID(id descpb.ID) *byIDEntry {
 	newEntry := &byIDEntry{
 		id: id,
 	}
-	if replaced := mc.byID.upsert(newEntry); replaced != nil {
-		*newEntry = *(replaced.(*byIDEntry))
+	if replaced := mc.ensureForIDWithEntry(newEntry); replaced != nil {
+		*newEntry = *replaced
 	} else {
 		mc.byteSize += newEntry.ByteSize()
 	}
 	return newEntry
 }
 
+// ensureForWithEntry upserts the entry and returns either the current entry or
+// the one that has replaced.
+func (mc *MutableCatalog) ensureForIDWithEntry(newEntry *byIDEntry) *byIDEntry {
+	mc.maybeInitialize()
+	if replaced := mc.byID.upsert(newEntry); replaced != nil {
+		return replaced.(*byIDEntry)
+	} else {
+		mc.byteSize += newEntry.ByteSize()
+	}
+	return nil
+}
+
 func (mc *MutableCatalog) maybeGetByID(id descpb.ID) *byIDEntry {
 	if !mc.IsInitialized() {
 		return nil
@@ -73,12 +85,22 @@ func (mc *MutableCatalog) ensureForName(key catalog.NameKey) *byNameEntry {
 		parentSchemaID: key.GetParentSchemaID(),
 		name:           key.GetName(),
 	}
+	if replaced := mc.ensureForNameWithEntry(newEntry); replaced != nil {
+		*newEntry = *replaced
+	}
+	return newEntry
+}
+
+// ensureForNameWithEntry upserts the entry and returns either the current entry or
+// the one that has replaced.
+func (mc *MutableCatalog) ensureForNameWithEntry(newEntry *byNameEntry) *byNameEntry {
+	mc.maybeInitialize()
 	if replaced := mc.byName.upsert(newEntry); replaced != nil {
-		*newEntry = *(replaced.(*byNameEntry))
+		return replaced.(*byNameEntry)
 	} else {
 		mc.byteSize += newEntry.ByteSize()
 	}
-	return newEntry
+	return nil
 }
 
 // DeleteByName removes all by-name mappings from the MutableCatalog.
@@ -197,17 +219,23 @@ func (mc *MutableCatalog) AddAll(c Catalog) {
 		return
 	}
 	_ = c.byName.ascend(func(entry catalog.NameEntry) error {
-		e := mc.ensureForName(entry)
-		mc.byteSize -= e.ByteSize()
-		*e = *(entry.(*byNameEntry))
-		mc.byteSize += e.ByteSize()
+		ne := entry.(*byNameEntry)
+		e := mc.ensureForNameWithEntry(ne)
+		if e != nil {
+			// Update the size since the entry was replaced.
+			mc.byteSize -= e.ByteSize()
+			mc.byteSize += ne.ByteSize()
+		}
 		return nil
 	})
 	_ = c.byID.ascend(func(entry catalog.NameEntry) error {
-		e := mc.ensureForID(entry.GetID())
-		mc.byteSize -= e.ByteSize()
-		*e = *(entry.(*byIDEntry))
-		mc.byteSize += e.ByteSize()
+		ne := entry.(*byIDEntry)
+		e := mc.ensureForIDWithEntry(ne)
+		if e != nil {
+			// Update the size since the entry was replaced.
+			mc.byteSize -= e.ByteSize()
+			mc.byteSize += ne.ByteSize()
+		}
 		return nil
 	})
 }