restore only required collections for config db

Author: defbin

pbm/oplog/restore.go

@@ -19,6 +19,7 @@ import (
 
 	"github.com/mongodb/mongo-tools/common/bsonutil"
 	"github.com/mongodb/mongo-tools/common/db"
+	"github.com/mongodb/mongo-tools/common/dumprestore"
 	"github.com/mongodb/mongo-tools/common/idx"
 	"github.com/mongodb/mongo-tools/common/txn"
 	"github.com/mongodb/mongo-tools/mongorestore/ns"
@@ -291,15 +292,21 @@ func (o *OplogRestore) handleOp(oe db.Oplog) error {
 		return nil
 	}
 
-	if o.excludeNS.Has(oe.Namespace) {
+	// skip no-ops
+	if oe.Operation == "n" {
 		return nil
 	}
 
-	// skip no-ops
-	if oe.Operation == "n" {
+	if o.excludeNS.Has(oe.Namespace) {
 		return nil
 	}
 
+	if db, coll, _ := strings.Cut(oe.Namespace, "."); db == "config" {
+		if !sliceContains(dumprestore.ConfigCollectionsToKeep, coll) {
+			return nil
+		}
+	}
+
 	if !o.isOpSelected(&oe) {
 		return nil
 	}
@@ -623,6 +630,12 @@ func (o *OplogRestore) handleNonTxnOp(op db.Oplog) error {
 		return nil
 	}
 
+	if db, coll, _ := strings.Cut(op.Namespace, "."); db == "config" {
+		if !sliceContains(dumprestore.ConfigCollectionsToKeep, coll) {
+			return nil
+		}
+	}
+
 	op, err := o.filterUUIDs(op)
 	if err != nil {
 		return errors.Wrap(err, "filtering UUIDs from oplog")

pbm/oplog/util.go

@@ -0,0 +1,10 @@
+package oplog
+
+func sliceContains[S ~[]E, E comparable](s S, v E) bool {
+	for i := range s {
+		if v == s[i] {
+			return true
+		}
+	}
+	return false
+}

pbm/snapshot/restore.go

@@ -32,19 +32,7 @@ var ExcludeFromRestore = []string{
 	defs.DB + "." + defs.PBMOpLogCollection,
 	"admin.system.version",
 	"config.version",
-	"config.mongos",
-	"config.lockpings",
-	"config.locks",
-	"config.system.sessions",
-	"config.cache.*",
 	"config.shards",
-	"config.transactions",
-	"config.transaction_coordinators",
-	"config.changelog",
-	"config.actionlog",
-	"config.image_collection",
-	"config.system.indexBuilds",
-	"config.system.sharding_ddl_coordinators",
 
 	// deprecated PBM collections, keep it here not to bring back from old backups
 	defs.DB + ".pbmBackups.old",