diff --git a/runbot/models/repo.py b/runbot/models/repo.py
index 24f6bb5c..5498f940 100644
--- a/runbot/models/repo.py
+++ b/runbot/models/repo.py
@@ -374,13 +374,17 @@ class Repo(models.Model):
     def _source_path(self, *path_parts):
         return self.env['runbot.runbot']._path('sources', sanitize(self.name), *path_parts)
 
-    def _git(self, cmd, errors='strict'):
+    def _get_git_command(self, cmd, errors='strict'):
         """Execute a git command 'cmd'"""
         self.ensure_one()
         config_args = []
         if self.identity_file:
             config_args = ['-c', 'core.sshCommand=ssh -i %s/.ssh/%s' % (str(Path.home()), self.identity_file)]
         cmd = ['git', '-C', self.path] + config_args + cmd
+        return cmd
+
+    def _git(self, cmd, errors='strict'):
+        cmd = self._get_git_command(cmd, errors)
         _logger.info("git command: %s", ' '.join(cmd))
         return subprocess.check_output(cmd, stderr=subprocess.STDOUT).decode(errors=errors)
 
diff --git a/runbot/models/runbot.py b/runbot/models/runbot.py
index b4c345d5..ed17fdf4 100644
--- a/runbot/models/runbot.py
+++ b/runbot/models/runbot.py
@@ -383,16 +383,6 @@ class Runbot(models.AbstractModel):
         if ignored:
             _logger.info('docker (%s) not deleted because not dest format', list(ignored))
 
-    def _git_gc(self, host):
-        """
-        cleanup and optimize git repositories on the host
-        """
-        for repo in self.env['runbot.repo'].search([]):
-            try:
-                repo._git(['gc', '--prune=all', '--quiet'])
-            except CalledProcessError as e:
-                message = f'git gc failed for {repo.name} on {host.name} with exit status {e.returncode} and message "{e.output[:60]} ..."'
-                self._warning(message)
 
     def _warning(self, message, *args):
         if args:
diff --git a/runbot_builder/builder.py b/runbot_builder/builder.py
index 4ddd3ea7..9d6697bf 100755
--- a/runbot_builder/builder.py
+++ b/runbot_builder/builder.py
@@ -28,7 +28,9 @@ class BuilderClient(RunbotClient):
             self.host._set_psql_conn_count()
             self.host._docker_build()
             self.env['runbot.repo']._update_git_config()
+            self.env.cr.commit()
             self.git_gc()
+            self.env.cr.commit()
         return self.env['runbot.runbot']._scheduler_loop_turn(self.host)
 
 
diff --git a/runbot_builder/leader.py b/runbot_builder/leader.py
index 91ece899..8e785759 100755
--- a/runbot_builder/leader.py
+++ b/runbot_builder/leader.py
@@ -20,7 +20,9 @@ class LeaderClient(RunbotClient):  # Conductor, Director, Main, Maestro, Lead
     def loop_turn(self):
         if self.count == 0:
             self.env['runbot.repo']._update_git_config()
+            self.env.cr.commit()
             self.git_gc()
+            self.env.cr.commit()
         return self.env['runbot.runbot']._fetch_loop_turn(self.host, self.pull_info_failures)
 
 
diff --git a/runbot_builder/tools.py b/runbot_builder/tools.py
index 0d9a023c..c5f4820c 100644
--- a/runbot_builder/tools.py
+++ b/runbot_builder/tools.py
@@ -9,6 +9,7 @@ import sys
 import threading
 import time
 import signal
+import subprocess
 
 from contextlib import nullcontext
 from datetime import datetime, timedelta, timezone
@@ -111,7 +112,25 @@ class RunbotClient():
         """ git gc once a day """
         if self.next_git_gc_date < datetime.now():
             _logger.info('Starting git gc on repositories')
-            self.env['runbot.runbot']._git_gc(self.host)
+            commands = []
+            host_name = self.host.name
+            for repo in self.env['runbot.repo'].search([]):
+                commands.append(repo.name, (repo._get_git_command(['gc', '--prune=all', '--quiet'])))
+            self.env.cr.rollback()
+            # gc commands can be slow, rollbacking to avoid to keep a transaction idle for multiple minutes.
+            messages = []
+            for repo_name, command in commands:
+                try:
+                    start = time.time()
+                    subprocess.check_output(command, stderr=subprocess.STDOUT).decode()
+                    _logger.info('Git gc on %s took %ss', repo_name, time.time() - start)
+                except subprocess.CalledProcessError as e:
+                    message = f'git gc failed for {repo_name} on {host_name} with exit status {e.returncode} and message "{e.output[:60]} ..."'
+                    messages.append(message)
+            for message in messages:
+                self.env['runbot.runbot']._warning(message)
+
+            self.env.cr.commit()
             self.update_next_git_gc_date()
 
 def run(client_class):