From 0026358bc071e5cf604e0194170a5a5f07accd83 Mon Sep 17 00:00:00 2001
From: Mateusz Gajewski <mateusz.gajewski@gmail.com>
Date: Fri, 1 Apr 2022 09:47:16 +0200
Subject: [PATCH] Add MySQL automatic Join pushdown test

---
 .../mysql/TestMySqlAutomaticJoinPushdown.java | 79 +++++++++++++++++++
 1 file changed, 79 insertions(+)
 create mode 100644 plugin/trino-mysql/src/test/java/io/trino/plugin/mysql/TestMySqlAutomaticJoinPushdown.java

diff --git a/plugin/trino-mysql/src/test/java/io/trino/plugin/mysql/TestMySqlAutomaticJoinPushdown.java b/plugin/trino-mysql/src/test/java/io/trino/plugin/mysql/TestMySqlAutomaticJoinPushdown.java
new file mode 100644
index 000000000000..55301f7854bf
--- /dev/null
+++ b/plugin/trino-mysql/src/test/java/io/trino/plugin/mysql/TestMySqlAutomaticJoinPushdown.java
@@ -0,0 +1,79 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.trino.plugin.mysql;
+
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
+import io.trino.plugin.jdbc.BaseAutomaticJoinPushdownTest;
+import io.trino.testing.MaterializedRow;
+import io.trino.testing.QueryRunner;
+import org.jdbi.v3.core.Handle;
+import org.jdbi.v3.core.Jdbi;
+import org.testng.SkipException;
+
+import static io.trino.plugin.mysql.MySqlQueryRunner.createMySqlQueryRunner;
+import static java.lang.String.format;
+
+public class TestMySqlAutomaticJoinPushdown
+        extends BaseAutomaticJoinPushdownTest
+{
+    private TestingMySqlServer mySqlServer;
+
+    @Override
+    protected QueryRunner createQueryRunner()
+            throws Exception
+    {
+        // Using MySQL 8.0.15 because test is sensitive to quality of NDV estimation and 5.5.46 we use
+        // in other places does very poor job; for 10000 row table with 1000 distinct keys it estimates NDV at ~2500
+        mySqlServer = closeAfterClass(new TestingMySqlServer("mysql:8.0.15", false));
+
+        return createMySqlQueryRunner(
+                mySqlServer,
+                ImmutableMap.of(),
+                ImmutableMap.<String, String>builder()
+                        .put("metadata.cache-ttl", "0m")
+                        .put("metadata.cache-missing", "false")
+                        .buildOrThrow(),
+                ImmutableList.of());
+    }
+
+    @Override
+    public void testJoinPushdownWithEmptyStatsInitially()
+    {
+        throw new SkipException("MySQL statistics are automatically collected");
+    }
+
+    @Override
+    protected void gatherStats(String tableName)
+    {
+        for (MaterializedRow row : computeActual("SHOW COLUMNS FROM " + tableName)) {
+            String columnName = (String) row.getField(0);
+            String columnType = (String) row.getField(1);
+            if (columnType.startsWith("varchar")) {
+                // varchar index require length
+                continue;
+            }
+            onRemoteDatabase(format("CREATE INDEX \"%2$s\" ON %1$s (\"%2$s\")", tableName, columnName).replace("\"", "`"));
+        }
+        onRemoteDatabase("ANALYZE TABLE " + tableName.replace("\"", "`"));
+    }
+
+    protected void onRemoteDatabase(String sql)
+    {
+        try (Handle handle = Jdbi.open(() -> mySqlServer.createConnection())) {
+            handle.execute("USE tpch");
+            handle.execute(sql);
+        }
+    }
+}