diff --git a/src/java/src/main/java/org/openapitools/config/DataSourceConfig.java b/src/java/src/main/java/org/openapitools/config/DataSourceConfig.java
index e9e58862..32e3e9d4 100644
--- a/src/java/src/main/java/org/openapitools/config/DataSourceConfig.java
+++ b/src/java/src/main/java/org/openapitools/config/DataSourceConfig.java
@@ -206,12 +206,25 @@ private void configureCloudSqlProperties(HikariConfig config, String jdbcUrl) {
 
     config.addDataSourceProperty("socketFactory", "com.google.cloud.sql.postgres.SocketFactory");
     config.addDataSourceProperty("unixSocketPath", instanceUnixSocket);
+    String cloudSqlInstance = extractCloudSqlInstance(instanceUnixSocket);
+    if (isNotBlank(cloudSqlInstance)) {
+      config.addDataSourceProperty("cloudSqlInstance", cloudSqlInstance);
+    }
 
     if (isCloudRun()) {
       config.addDataSourceProperty("cloudSqlRefreshStrategy", "lazy");
     }
   }
 
+  private String extractCloudSqlInstance(String unixSocketPath) {
+    final String prefix = "/cloudsql/";
+    if (!isNotBlank(unixSocketPath) || !unixSocketPath.startsWith(prefix)) {
+      return null;
+    }
+    String instanceConnectionName = unixSocketPath.substring(prefix.length());
+    return isNotBlank(instanceConnectionName) ? instanceConnectionName : null;
+  }
+
   private String extractUnixSocketPath(String jdbcUrl) {
     String rawQuery = extractRawQuery(jdbcUrl);
     if (!isNotBlank(rawQuery)) {
diff --git a/src/java/src/test/java/org/openapitools/config/DataSourceConfigTest.java b/src/java/src/test/java/org/openapitools/config/DataSourceConfigTest.java
index 6cef1c35..01c15608 100644
--- a/src/java/src/test/java/org/openapitools/config/DataSourceConfigTest.java
+++ b/src/java/src/test/java/org/openapitools/config/DataSourceConfigTest.java
@@ -95,6 +95,7 @@ void hikariConfig_ShouldNormalizeCloudSqlSocketStyleDatabaseUrl() throws Excepti
     assertThat(result.getDataSourceProperties())
         .containsEntry("socketFactory", "com.google.cloud.sql.postgres.SocketFactory")
         .containsEntry("unixSocketPath", "/cloudsql/project-id:region:instance-id")
+        .containsEntry("cloudSqlInstance", "project-id:region:instance-id")
         .doesNotContainKey("cloudSqlRefreshStrategy");
   }
 
@@ -120,6 +121,7 @@ void hikariConfig_ShouldSetCloudSqlRefreshStrategyOnCloudRunInSocketMode() throw
     assertThat(result.getDataSourceProperties())
         .containsEntry("socketFactory", "com.google.cloud.sql.postgres.SocketFactory")
         .containsEntry("unixSocketPath", "/cloudsql/project-id:region:instance-id")
+        .containsEntry("cloudSqlInstance", "project-id:region:instance-id")
         .containsEntry("cloudSqlRefreshStrategy", "lazy");
   }
 
diff --git a/src/kotlin/src/main/kotlin/com/lampcontrol/database/DatabaseFactory.kt b/src/kotlin/src/main/kotlin/com/lampcontrol/database/DatabaseFactory.kt
index 4c98cdfa..90b737b4 100644
--- a/src/kotlin/src/main/kotlin/com/lampcontrol/database/DatabaseFactory.kt
+++ b/src/kotlin/src/main/kotlin/com/lampcontrol/database/DatabaseFactory.kt
@@ -76,6 +76,10 @@ object DatabaseFactory {
 
         hikariConfig.addDataSourceProperty("socketFactory", CLOUD_SQL_SOCKET_FACTORY)
         hikariConfig.addDataSourceProperty("unixSocketPath", config.host)
+        val cloudSqlInstance = extractCloudSqlInstance(config.host)
+        if (cloudSqlInstance != null) {
+            hikariConfig.addDataSourceProperty("cloudSqlInstance", cloudSqlInstance)
+        }
 
         val cloudRunService = System.getenv("K_SERVICE")
         val cloudRunRevision = System.getenv("K_REVISION")
@@ -83,6 +87,11 @@ object DatabaseFactory {
             hikariConfig.addDataSourceProperty("cloudSqlRefreshStrategy", "lazy")
         }
     }
+
+    private fun extractCloudSqlInstance(unixSocketPath: String): String? {
+        val instance = unixSocketPath.removePrefix(CLOUD_SQL_PATH_PREFIX)
+        return instance.takeIf { it.isNotBlank() }
+    }
 }
 
 /**
diff --git a/src/kotlin/src/test/kotlin/com/lampcontrol/database/DatabaseFactoryTest.kt b/src/kotlin/src/test/kotlin/com/lampcontrol/database/DatabaseFactoryTest.kt
index 0195f05a..35824871 100644
--- a/src/kotlin/src/test/kotlin/com/lampcontrol/database/DatabaseFactoryTest.kt
+++ b/src/kotlin/src/test/kotlin/com/lampcontrol/database/DatabaseFactoryTest.kt
@@ -1,6 +1,8 @@
 package com.lampcontrol.database
 
+import com.zaxxer.hikari.HikariConfig
 import org.junit.jupiter.api.Test
+import kotlin.test.assertEquals
 import kotlin.test.assertNotNull
 
 class DatabaseFactoryTest {
@@ -32,4 +34,44 @@ class DatabaseFactoryTest {
         // Verify DatabaseFactory object can be accessed
         assertNotNull(DatabaseFactory)
     }
+
+    @Test
+    fun `configureCloudSqlProperties sets cloudSqlInstance from unix socket path`() {
+        val hikariConfig = HikariConfig()
+        val config =
+            DatabaseConfig(
+                host = "/cloudsql/project:region:instance-id",
+                port = 5432,
+                database = "lamp-control",
+                user = "postgres",
+                password = "secret",
+                poolMin = 0,
+                poolMax = 4,
+                maxLifetimeMs = 3600000,
+                idleTimeoutMs = 1800000,
+                connectionTimeoutMs = 30000,
+            )
+
+        val configureMethod =
+            DatabaseFactory::class.java.getDeclaredMethod(
+                "configureCloudSqlProperties",
+                HikariConfig::class.java,
+                DatabaseConfig::class.java,
+            )
+        configureMethod.isAccessible = true
+        configureMethod.invoke(DatabaseFactory, hikariConfig, config)
+
+        assertEquals(
+            "com.google.cloud.sql.postgres.SocketFactory",
+            hikariConfig.dataSourceProperties["socketFactory"],
+        )
+        assertEquals(
+            "/cloudsql/project:region:instance-id",
+            hikariConfig.dataSourceProperties["unixSocketPath"],
+        )
+        assertEquals(
+            "project:region:instance-id",
+            hikariConfig.dataSourceProperties["cloudSqlInstance"],
+        )
+    }
 }