diff --git a/packages/pg-protocol/src/serializer.ts b/packages/pg-protocol/src/serializer.ts
index 07e2fe498..4adb3f331 100644
--- a/packages/pg-protocol/src/serializer.ts
+++ b/packages/pg-protocol/src/serializer.ts
@@ -26,6 +26,7 @@ const startup = (opts: Record<string, string>): Buffer => {
   }
 
   writer.addCString('client_encoding').addCString('UTF8')
+  writer.addCString('extra_float_digits').addCString('1')
 
   var bodyBuffer = writer.addCString('').flush()
   // this message is sent without a code
diff --git a/packages/pg/test/integration/client/type-coercion-tests.js b/packages/pg/test/integration/client/type-coercion-tests.js
index 587a28c61..84c0910c9 100644
--- a/packages/pg/test/integration/client/type-coercion-tests.js
+++ b/packages/pg/test/integration/client/type-coercion-tests.js
@@ -109,7 +109,7 @@ var types = [
   },
   {
     name: 'double precision',
-    values: [-101.3, -1.2, 0, 1.2, 101.1, null],
+    values: [-101.3, -1.2, 0, 1.2, 101.1, Number.MAX_SAFE_INTEGER, null],
   },
   {
     name: 'timestamptz',