Optimize replication information retrieval scope for improved perform…

…ance

Modified the scope of replication information retrieval.
Previously, sub scope was used, which fetched all entries under the base DN.
Changed it to base to retrieve information only from the base DN itself.
This change improves performance by limiting the scope of the query.

main.go

@@ -203,6 +203,7 @@ const (
 
 type query struct {
 	baseDN       string
+	scope        int
 	searchFilter string
 	searchAttr   string
 	metric       *prometheus.GaugeVec
@@ -277,26 +278,30 @@ var (
 	queries = []*query{
 		{
 			baseDN:       baseDN,
+			scope:        ldap.ScopeWholeSubtree,
 			searchFilter: objectClass(monitoredObject),
 			searchAttr:   monitoredInfo,
 			metric:       monitoredObjectGauge,
 			setData:      setValue,
 		}, {
 			baseDN:       baseDN,
+			scope:        ldap.ScopeWholeSubtree,
 			searchFilter: objectClass(monitorCounterObject),
 			searchAttr:   monitorCounter,
 			metric:       monitorCounterObjectGauge,
 			setData:      setValue,
 		},
 		{
 			baseDN:       opsBaseDN,
+			scope:        ldap.ScopeWholeSubtree,
 			searchFilter: objectClass(monitorOperation),
 			searchAttr:   monitorOpCompleted,
 			metric:       monitorOperationGauge,
 			setData:      setValue,
 		},
 		{
 			baseDN:       opsBaseDN,
+			scope:        ldap.ScopeWholeSubtree,
 			searchFilter: objectClass(monitorOperation),
 			searchAttr:   monitorOpCompleted,
 			metric:       monitorOperationGauge,
@@ -376,6 +381,7 @@ func (s *Scraper) addReplicationQueries() {
 		queries = append(queries,
 			&query{
 				baseDN:       s.Sync,
+				scope:        ldap.ScopeBaseObject,
 				searchFilter: "(contextCSN=*)",
 				searchAttr:   monitorReplicationFilter,
 				metric:       monitorReplicationGauge,
@@ -498,7 +504,7 @@ func (s *Scraper) scrapeReplication() []ReplicaStatus {
 		}
 
 		req := ldap.NewSearchRequest(
-			s.Sync, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 0, false,
+			s.Sync, ldap.ScopeBaseObject, ldap.NeverDerefAliases, 0, 0, false,
 			"(contextCSN=*)", []string{monitorReplicationFilter}, nil,
 		)
 		sr, err := replica.Search(req)
@@ -549,7 +555,7 @@ func (s *Scraper) scrapeReplication() []ReplicaStatus {
 
 func scrapeQuery(conn *ldap.Conn, q *query) error {
 	req := ldap.NewSearchRequest(
-		q.baseDN, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 0, false,
+		q.baseDN, q.scope, ldap.NeverDerefAliases, 0, 0, false,
 		q.searchFilter, []string{q.searchAttr}, nil,
 	)
 	sr, err := conn.Search(req)