From f4cdcb995c576313b32ab268ee246c627b25d11b Mon Sep 17 00:00:00 2001
From: Sarah Hoffmann <lonvia@denofr.de>
Date: Sat, 8 Jul 2023 19:38:54 +0200
Subject: [PATCH] force a fixed pool size and make it configurable

---
 nominatim/api/core.py | 2 ++
 settings/env.defaults | 5 +++++
 2 files changed, 7 insertions(+)

diff --git a/nominatim/api/core.py b/nominatim/api/core.py
index 2a19d974..32d420db 100644
--- a/nominatim/api/core.py
+++ b/nominatim/api/core.py
@@ -54,6 +54,7 @@ class NominatimAPIAsync:
                 return
 
             dsn = self.config.get_database_params()
+            pool_size = self.config.get_int('API_POOL_SIZE')
 
             query = {k: v for k, v in dsn.items()
                       if k not in ('user', 'password', 'dbname', 'host', 'port')}
@@ -65,6 +66,7 @@ class NominatimAPIAsync:
                        host=dsn.get('host'), port=int(dsn['port']) if 'port' in dsn else None,
                        query=query)
             engine = sa_asyncio.create_async_engine(dburl, future=True,
+                                                    max_overflow=0, pool_size=pool_size,
                                                     echo=self.config.get_bool('DEBUG_SQL'))
 
             try:
diff --git a/settings/env.defaults b/settings/env.defaults
index 9c2f7cac..f9f590da 100644
--- a/settings/env.defaults
+++ b/settings/env.defaults
@@ -209,6 +209,11 @@ NOMINATIM_POLYGON_OUTPUT_MAX_TYPES=1
 # under <endpoint>.php
 NOMINATIM_SERVE_LEGACY_URLS=yes
 
+# Maximum number of connection a single API object can use. (Python API only)
+# When running Nominatim as a server, then this is the maximum number
+# of connections _per worker_.
+NOMINATIM_API_POOL_SIZE=10
+
 ### Log settings
 #
 # The following options allow to enable logging of API requests.