lncfg+scripts: use configurable global lock for postgres backends

diff --git a/docs/postgres.md b/docs/postgres.md
index 423efc7..89b16eb 100644
--- a/docs/postgres.md
+++ b/docs/postgres.md
@@ -42,6 +42,16 @@ db.postgres.timeout=0
 Connection timeout is disabled, to account for situations where the database
 might be slow for unexpected reasons.
 
+Moreover for particular kv tables we also add the option to access the
+tables via a global lock (single wirter). This is a temorpary measure until 
+these particular tables have a native sql schema. This helps to mitigate
+resource exhaustion in case LND experiencing high concurrent load:
+
+* `db.postgres.walletdb-with-global-lock=true` to run LND with a single writer
+  for the walletdb_kv table (default is true).
+* `db.postgres.channeldb-with-global-lock=false` to run the channeldb_kv table
+  with a single writer (default is false).
+
 ## Important note about replication
 
 In case a replication architecture is planned, streaming replication should be avoided, as the master does not verify the replica is indeed identical, but it will only forward the edits queue, and let the slave catch up autonomously; synchronous mode, albeit slower, is paramount for `lnd` data integrity across the copies, as it will finalize writes only after the slave confirmed successful replication.
diff --git a/lncfg/db.go b/lncfg/db.go
index 9eb0278..5bd4d2e 100644
--- a/lncfg/db.go
+++ b/lncfg/db.go
@@ -115,7 +115,15 @@ func DefaultDB() *DB {
 		},
 		Postgres: &sqldb.PostgresConfig{
 			MaxConnections: defaultPostgresMaxConnections,
-			QueryConfig:    *sqldb.DefaultPostgresConfig(),
+			// Normally we don't use a global lock for channeldb
+			// access, but if a user encounters huge concurrency
+			// issues, they can enable this to use a global lock.
+			ChannelDBWithGlobalLock: false,
+			// Default to true to maintain safe single-writer
+			// behavior until the wallet subsystem is upgraded to
+			// a native sql schema.
+			WalletDBWithGlobalLock: true,
+			QueryConfig:            *sqldb.DefaultPostgresConfig(),
 		},
 		Sqlite: &sqldb.SqliteConfig{
 			MaxConnections: defaultSqliteMaxConnections,
@@ -400,9 +408,15 @@ func (db *DB) GetBackends(ctx context.Context, chanDBPath,
 		// users to native SQL.
 		postgresConfig := GetPostgresConfigKVDB(db.Postgres)
 
+		// Create a separate config for channeldb with the global lock
+		// setting if configured.
+		postgresConfigChannelDB := GetPostgresConfigKVDB(db.Postgres)
+		postgresConfigChannelDB.WithGlobalLock = db.Postgres.
+			ChannelDBWithGlobalLock
+
 		postgresBackend, err := kvdb.Open(
 			kvdb.PostgresBackendName, ctx,
-			postgresConfig, NSChannelDB,
+			postgresConfigChannelDB, NSChannelDB,
 		)
 		if err != nil {
 			return nil, fmt.Errorf("error opening postgres graph "+
@@ -450,14 +464,11 @@ func (db *DB) GetBackends(ctx context.Context, chanDBPath,
 		}
 		closeFuncs[NSTowerServerDB] = postgresTowerServerBackend.Close
 
-		// The wallet subsystem is still not robust enough to run it
-		// without a single writer in postgres therefore we create a
-		// new config with the global lock enabled.
-		//
-		// NOTE: This is a temporary measure and should be removed as
-		// soon as the wallet code is more robust.
+		// Create a separate config for wallet with the global lock
+		// setting if configured.
 		postgresConfigWalletDB := GetPostgresConfigKVDB(db.Postgres)
-		postgresConfigWalletDB.WithGlobalLock = true
+		postgresConfigWalletDB.WithGlobalLock = db.Postgres.
+			WalletDBWithGlobalLock
 
 		postgresWalletBackend, err := kvdb.Open(
 			kvdb.PostgresBackendName, ctx,
diff --git a/sample-lnd.conf b/sample-lnd.conf
index ed5dabd..c9a2865 100644
--- a/sample-lnd.conf
+++ b/sample-lnd.conf
@@ -1625,6 +1625,17 @@
 ; Whether to skip executing schema migrations.
 ; db.postgres.skipmigrations=false
 
+; Use a global lock for channeldb access. This ensures only a single writer at
+; a time but reduces concurrency. This is a temporary workaround until the
+; revocation log is migrated to native SQL.
+; db.postgres.channeldb-with-global-lock=false
+
+
+; Use a global lock for wallet database access. This is a temporary workaround 
+; until the wallet subsystem is upgraded to a native sql schema.
+; db.postgres.walletdb-with-global-lock=true
+
+
 ; The maximum number of elements to use in a native-SQL batch query IN clause.
 ; db.postgres.query.max-batch-size=5000
 
diff --git a/scripts/check-sample-lnd-conf.sh b/scripts/check-sample-lnd-conf.sh
index 48cbad7..0f51e47 100755
--- a/scripts/check-sample-lnd-conf.sh
+++ b/scripts/check-sample-lnd-conf.sh
@@ -59,7 +59,7 @@ OPTIONS_NO_LND_DEFAULT_VALUE_CHECK="channel-max-fee-exposure adminmacaroonpath \
     backupfilepath maxchansize bitcoin.chaindir bitcoin.defaultchanconfs \
     bitcoin.defaultremotedelay bitcoin.dnsseed signrpc.signermacaroonpath \
     walletrpc.walletkitmacaroonpath chainrpc.notifiermacaroonpath \
-    routerrpc.routermacaroonpath" 
+    routerrpc.routermacaroonpath db.postgres.walletdb-with-global-lock" 
 
 
 # EXITCODE is returned at the end after all checks are performed and set to 1