diff --git a/code/services-application/search-service/java/nu/marginalia/search/svc/SearchAddToCrawlQueueService.java b/code/services-application/search-service/java/nu/marginalia/search/svc/SearchAddToCrawlQueueService.java
index c43535dd..4e2d2a0d 100644
--- a/code/services-application/search-service/java/nu/marginalia/search/svc/SearchAddToCrawlQueueService.java
+++ b/code/services-application/search-service/java/nu/marginalia/search/svc/SearchAddToCrawlQueueService.java
@@ -47,18 +47,23 @@ public class SearchAddToCrawlQueueService {
         return new MapModelAndView("redirect.jte", Map.of("url", "/site/"+domainName));
     }
 
-    private void addToCrawlQueue(int id) throws SQLException {
+    /** Mark a domain for crawling by setting node affinity to zero,
+     * unless it is already marked for crawling, then node affinity should
+     * be left unchanged.
+     * */
+    void addToCrawlQueue(int domainId) throws SQLException {
         try (var conn = dataSource.getConnection();
              var stmt = conn.prepareStatement("""
-                     INSERT IGNORE INTO CRAWL_QUEUE(DOMAIN_NAME, SOURCE)
-                     SELECT DOMAIN_NAME, "user" FROM EC_DOMAIN WHERE ID=?
+                     UPDATE EC_DOMAIN 
+                     SET WMSA_prod.EC_DOMAIN.NODE_AFFINITY = 0 
+                     WHERE ID=? AND WMSA_prod.EC_DOMAIN.NODE_AFFINITY < 0
                      """)) {
-            stmt.setInt(1, id);
+            stmt.setInt(1, domainId);
             stmt.executeUpdate();
         }
     }
 
-    private String getDomainName(int id) {
+    String getDomainName(int id) {
         var domain = domainQueries.getDomain(id);
         if (domain.isEmpty())
             throw new IllegalArgumentException();
diff --git a/code/services-application/search-service/test/nu/marginalia/search/svc/SearchAddToCrawlQueueServiceTest.java b/code/services-application/search-service/test/nu/marginalia/search/svc/SearchAddToCrawlQueueServiceTest.java
new file mode 100644
index 00000000..f9453435
--- /dev/null
+++ b/code/services-application/search-service/test/nu/marginalia/search/svc/SearchAddToCrawlQueueServiceTest.java
@@ -0,0 +1,85 @@
+package nu.marginalia.search.svc;
+
+import com.zaxxer.hikari.HikariConfig;
+import com.zaxxer.hikari.HikariDataSource;
+import nu.marginalia.db.DbDomainQueries;
+import nu.marginalia.model.EdgeDomain;
+import nu.marginalia.test.TestMigrationLoader;
+import org.junit.jupiter.api.*;
+import org.testcontainers.containers.MariaDBContainer;
+import org.testcontainers.junit.jupiter.Container;
+import org.testcontainers.junit.jupiter.Testcontainers;
+
+import java.sql.SQLException;
+
+@Tag("slow")
+@Testcontainers
+class SearchAddToCrawlQueueServiceTest {
+    @Container
+    static MariaDBContainer<?> mariaDBContainer = new MariaDBContainer<>("mariadb")
+            .withDatabaseName("WMSA_prod")
+            .withUsername("wmsa")
+            .withPassword("wmsa")
+            .withNetworkAliases("mariadb");
+
+    static HikariDataSource dataSource;
+
+    private DbDomainQueries domainQueries;
+    private SearchAddToCrawlQueueService addToCrawlQueueService;
+
+    @BeforeEach
+    public void setUp() throws SQLException {
+        try (var conn = dataSource.getConnection();
+             var stmt = conn.createStatement()) {
+            stmt.executeQuery("DELETE FROM EC_DOMAIN"); // Wipe any old state from other test runs
+
+            stmt.executeQuery("INSERT INTO EC_DOMAIN (DOMAIN_NAME, DOMAIN_TOP, NODE_AFFINITY) VALUES ('known.example.com', 'example.com', -1)");
+            stmt.executeQuery("INSERT INTO EC_DOMAIN (DOMAIN_NAME, DOMAIN_TOP, NODE_AFFINITY) VALUES ('added.example.com', 'example.com', 0)");
+            stmt.executeQuery("INSERT INTO EC_DOMAIN (DOMAIN_NAME, DOMAIN_TOP, NODE_AFFINITY) VALUES ('indexed.example.com', 'example.com', 1)");
+        }
+
+        domainQueries = new DbDomainQueries(dataSource);
+        addToCrawlQueueService = new SearchAddToCrawlQueueService(domainQueries, dataSource);
+    }
+
+    @BeforeAll
+    public static void setUpAll() {
+        HikariConfig config = new HikariConfig();
+        config.setJdbcUrl(mariaDBContainer.getJdbcUrl());
+        config.setUsername("wmsa");
+        config.setPassword("wmsa");
+
+        dataSource = new HikariDataSource(config);
+        TestMigrationLoader.flywayMigration(dataSource);
+    }
+
+    private int getNodeAffinity(String domainName) throws SQLException {
+        try (var conn = dataSource.getConnection();
+             var stmt = conn.prepareStatement("SELECT NODE_AFFINITY FROM EC_DOMAIN WHERE DOMAIN_NAME=?"))
+        {
+            stmt.setString(1, domainName);
+            var rsp = stmt.executeQuery();
+            if (rsp.next()) {
+                return rsp.getInt(1);
+            }
+        }
+
+        return -1;
+    }
+
+    @Test
+    void addToCrawlQueue() throws SQLException {
+        int knownId = domainQueries.getDomainId(new EdgeDomain("known.example.com"));
+        int addedId = domainQueries.getDomainId(new EdgeDomain("added.example.com"));
+        int indexedId = domainQueries.getDomainId(new EdgeDomain("indexed.example.com"));
+
+        addToCrawlQueueService.addToCrawlQueue(knownId);
+        addToCrawlQueueService.addToCrawlQueue(addedId);
+        addToCrawlQueueService.addToCrawlQueue(indexedId);
+
+        Assertions.assertEquals(0, getNodeAffinity("known.example.com"));
+        Assertions.assertEquals(0, getNodeAffinity("added.example.com"));
+        Assertions.assertEquals(1, getNodeAffinity("indexed.example.com"));
+    }
+
+}
\ No newline at end of file