diff --git a/pkg/sql/opt/partialidx/implicator.go b/pkg/sql/opt/partialidx/implicator.go
index 090721d39349..fbda9407d705 100644
--- a/pkg/sql/opt/partialidx/implicator.go
+++ b/pkg/sql/opt/partialidx/implicator.go
@@ -145,7 +145,6 @@ func (im *Implicator) Init(f *norm.Factory, md *opt.Metadata, evalCtx *tree.Eval
 	im.f = f
 	im.md = md
 	im.evalCtx = evalCtx
-	im.constraintCache = make(map[opt.ScalarExpr]constraintCacheItem)
 }
 
 // FiltersImplyPredicate attempts to prove that a partial index predicate is
@@ -647,9 +646,18 @@ func (im *Implicator) twoVarComparisonImpliesTwoVarComparison(
 	return false, true
 }
 
+// initConstraintCache initializes the constraintCache field if it has not yet
+// been initialized.
+func (im *Implicator) initConstraintCache() {
+	if im.constraintCache == nil {
+		im.constraintCache = make(map[opt.ScalarExpr]constraintCacheItem)
+	}
+}
+
 // cacheConstraint caches a constraint set and a tight boolean for the given
 // scalar expression.
 func (im *Implicator) cacheConstraint(e opt.ScalarExpr, c *constraint.Set, tight bool) {
+	im.initConstraintCache()
 	if _, ok := im.constraintCache[e]; !ok {
 		im.constraintCache[e] = constraintCacheItem{
 			c:     c,
@@ -662,6 +670,7 @@ func (im *Implicator) cacheConstraint(e opt.ScalarExpr, c *constraint.Set, tight
 // cache contains an entry for the given scalar expression. It returns
 // ok = false if the scalar expression does not exist in the cache.
 func (im *Implicator) fetchConstraint(e opt.ScalarExpr) (_ *constraint.Set, tight bool, ok bool) {
+	im.initConstraintCache()
 	if res, ok := im.constraintCache[e]; ok {
 		return res.c, res.tight, true
 	}
diff --git a/pkg/sql/opt/xform/optimizer.go b/pkg/sql/opt/xform/optimizer.go
index 1f25de55acc7..1ce78755c03c 100644
--- a/pkg/sql/opt/xform/optimizer.go
+++ b/pkg/sql/opt/xform/optimizer.go
@@ -95,7 +95,7 @@ type Optimizer struct {
 	disabledRules RuleSet
 
 	// JoinOrderBuilder adds new join orderings to the memo.
-	jb *JoinOrderBuilder
+	jb JoinOrderBuilder
 }
 
 // Init initializes the Optimizer with a new, blank memo structure inside. This
@@ -112,7 +112,7 @@ func (o *Optimizer) Init(evalCtx *tree.EvalContext, catalog cat.Catalog) {
 	o.matchedRule = nil
 	o.appliedRule = nil
 	o.disabledRules = util.FastIntSet{}
-	o.jb = &JoinOrderBuilder{}
+	o.jb = JoinOrderBuilder{}
 	if evalCtx.TestingKnobs.DisableOptimizerRuleProbability > 0 {
 		o.disableRules(evalCtx.TestingKnobs.DisableOptimizerRuleProbability)
 	}
@@ -151,7 +151,7 @@ func (o *Optimizer) SetCoster(coster Coster) {
 // JoinOrderBuilder returns the JoinOrderBuilder instance that the optimizer is
 // currently using to reorder join trees.
 func (o *Optimizer) JoinOrderBuilder() *JoinOrderBuilder {
-	return o.jb
+	return &o.jb
 }
 
 // DisableOptimizations disables all transformation rules, including normalize