Add schema migration to fix wrong primary key column order

For 2.9 and 2.10 this was an init step which was removed in master
as, in master, we can do that as a schema migration.

Basically, this change just converts the UpdatePrimaryKeys init step
into a schema migration.

Change-Id: Ib5b025468f9724d762468d33b5adcc5d71eee57b

gerrit-server/src/main/java/com/google/gerrit/server/schema/SchemaVersion.java

@@ -32,7 +32,7 @@ import java.util.List;
 /** A version of the database schema. */
 public abstract class SchemaVersion {
   /** The current schema version. */
-  public static final Class<Schema_100> C = Schema_100.class;
+  public static final Class<Schema_101> C = Schema_101.class;
 
   public static class Module extends AbstractModule {
     @Override

gerrit-server/src/main/java/com/google/gerrit/server/schema/Schema_101.java

@@ -0,0 +1,156 @@
+// Copyright (C) 2014 The Android Open Source Project
+//
+// 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 com.google.gerrit.server.schema;
+
+import com.google.common.base.Joiner;
+import com.google.gerrit.reviewdb.server.ReviewDb;
+import com.google.gwtorm.jdbc.JdbcExecutor;
+import com.google.gwtorm.jdbc.JdbcSchema;
+import com.google.gwtorm.schema.ColumnModel;
+import com.google.gwtorm.schema.RelationModel;
+import com.google.gwtorm.schema.java.JavaSchemaModel;
+import com.google.gwtorm.schema.sql.DialectPostgreSQL;
+import com.google.gwtorm.schema.sql.SqlDialect;
+import com.google.gwtorm.server.OrmException;
+import com.google.gwtorm.server.StatementExecutor;
+import com.google.inject.Inject;
+import com.google.inject.Provider;
+
+import java.sql.Connection;
+import java.sql.DatabaseMetaData;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.TreeMap;
+
+public class Schema_101 extends SchemaVersion {
+
+  private static class PrimaryKey {
+    String oldNameInDb;
+    List<String> cols;
+  }
+
+  private Connection conn;
+  private SqlDialect dialect;
+
+  @Inject
+  Schema_101(Provider<Schema_100> prior) {
+    super(prior);
+  }
+
+  @Override
+  protected void migrateData(ReviewDb db, UpdateUI ui)
+      throws OrmException, SQLException {
+    conn = ((JdbcSchema) db).getConnection();
+    dialect = ((JdbcSchema) db).getDialect();
+    Map<String, PrimaryKey> corrections = findPKUpdates();
+    if (corrections.isEmpty()) {
+      return;
+    }
+
+    ui.message("Wrong Primary Key Column Order Detected");
+    ui.message("The following tables are affected:");
+    ui.message(Joiner.on(", ").join(corrections.keySet()));
+    ui.message("fixing primary keys...");
+    JdbcExecutor executor = new JdbcExecutor(conn);
+    try {
+      for (Map.Entry<String, PrimaryKey> c : corrections.entrySet()) {
+        ui.message(String.format("  table: %s ... ", c.getKey()));
+        recreatePK(executor, c.getKey(), c.getValue(), ui);
+        ui.message("done");
+      }
+      ui.message("done");
+    } finally {
+      executor.close();
+    }
+  }
+
+  private Map<String, PrimaryKey> findPKUpdates()
+      throws OrmException, SQLException {
+    Map<String, PrimaryKey> corrections = new TreeMap<>();
+    DatabaseMetaData meta = conn.getMetaData();
+    JavaSchemaModel jsm = new JavaSchemaModel(ReviewDb.class);
+    for (RelationModel rm : jsm.getRelations()) {
+      String tableName = rm.getRelationName();
+      List<String> expectedPKCols = relationPK(rm);
+      PrimaryKey actualPK = dbTablePK(meta, tableName);
+      if (!expectedPKCols.equals(actualPK.cols)) {
+        actualPK.cols = expectedPKCols;
+        corrections.put(tableName, actualPK);
+      }
+    }
+    return corrections;
+  }
+
+  private List<String> relationPK(RelationModel rm) {
+    Collection<ColumnModel> cols = rm.getPrimaryKeyColumns();
+    List<String> pk = new ArrayList<>(cols.size());
+    for (ColumnModel cm : cols) {
+      pk.add(cm.getColumnName().toLowerCase(Locale.US));
+    }
+    return pk;
+  }
+
+  private PrimaryKey dbTablePK(DatabaseMetaData meta, String tableName)
+      throws SQLException {
+    if (meta.storesUpperCaseIdentifiers()) {
+      tableName = tableName.toUpperCase();
+    } else if (meta.storesLowerCaseIdentifiers()) {
+      tableName = tableName.toLowerCase();
+    }
+
+    ResultSet cols = meta.getPrimaryKeys(null, null, tableName);
+    try {
+      PrimaryKey pk = new PrimaryKey();
+      Map<Short, String> seqToName = new TreeMap<>();
+      while (cols.next()) {
+        seqToName.put(cols.getShort("KEY_SEQ"), cols.getString("COLUMN_NAME"));
+        if (pk.oldNameInDb == null) {
+          pk.oldNameInDb = cols.getString("PK_NAME");
+        }
+      }
+
+      pk.cols = new ArrayList<>(seqToName.size());
+      for (String name : seqToName.values()) {
+        pk.cols.add(name.toLowerCase(Locale.US));
+      }
+      return pk;
+    } finally {
+      cols.close();
+    }
+  }
+
+  private void recreatePK(StatementExecutor executor, String tableName,
+      PrimaryKey pk, UpdateUI ui) throws OrmException {
+    if (pk.oldNameInDb == null) {
+      ui.message(String.format(
+          "warning: primary key for table %s didn't exist ... ", tableName));
+    } else {
+      if (dialect instanceof DialectPostgreSQL) {
+        // postgresql doesn't support the ALTER TABLE foo DROP PRIMARY KEY form
+        executor.execute("ALTER TABLE " + tableName + " DROP CONSTRAINT "
+            + pk.oldNameInDb);
+      } else {
+        executor.execute("ALTER TABLE " + tableName + " DROP PRIMARY KEY");
+      }
+    }
+    executor.execute("ALTER TABLE " + tableName
+        + " ADD PRIMARY KEY(" + Joiner.on(",").join(pk.cols) + ")");
+  }
+}