Support Jdbc implementation of AccountPatchReviewStore

Provide in gerrit core support for alternative database backends
for AccountPatchReview store.

H2 was used for storing AccountPatchReview. This can become
problematic in large installation since embedded H2 cannot execute
concurrent requests even to the same database. The options related to
multi-thread in H2 are:
- MULTI_THREADED: a long running query blocks the ones in other
threads [1].
- MVCC: This is not production-ready yet, since it is not fully
tested [2].

AccountPatchReviewStore is an extension and a plugin could
implement a jdbc store but this would result in duplicated code
with core H2 implementation. Since core H2 implementation was
almost already compliant to jdbc standard, it's easy to make
jdbc url configurable in gerrit config and make the core support
other database than H2.

One could extend the H2 implementation in plugin, however the
changes on the supper class could lead to breaking plugin
implementation.

[1] http://www.h2database.com/html/features.html#multiple_connections
[2] http://www.h2database.com/html/advanced.html#mvcc

Change-Id: Ie61ac63a72cab71bd907886a794541cb3dea291e
diff --git a/Documentation/config-gerrit.txt b/Documentation/config-gerrit.txt
index d796fa4..0a28534 100644
--- a/Documentation/config-gerrit.txt
+++ b/Documentation/config-gerrit.txt
@@ -19,6 +19,26 @@
   directory = /var/cache/gerrit2
 ----
 
+[[accountPatchReviewDb]]
+=== Section accountPatchReviewDb
+
+[[accountPatchReviewDb.url]]accountPatchReviewDb.url::
++
+The url of accountPatchReviewDb. Supported types are `H2`, `POSTGRESQL`, and
+`MYSQL`. Drop the driver jar in the lib folder of the site path if the Jdbc
+driver of the corresponding Database is not yet in the class path.
++
+Default is to create H2 database in the db folder of the site path.
++
+Changing this parameter requires to migrate database using the
+link:pgm-MigrateAccountPatchReviewDb.html[MigrateAccountPatchReviewDb program]
+before restarting the Gerrit server.
+
+----
+[accountPatchReviewDb]
+  url = jdbc:postgresql://<host>:<port>/<db_name>?user=<user>&password=<password>
+----
+
 [[accounts]]
 === Section accounts
 
diff --git a/Documentation/pgm-MigrateAccountPatchReviewDb.txt b/Documentation/pgm-MigrateAccountPatchReviewDb.txt
new file mode 100644
index 0000000..e353ffd
--- /dev/null
+++ b/Documentation/pgm-MigrateAccountPatchReviewDb.txt
@@ -0,0 +1,62 @@
+= MigrateAccountPatchReviewDb
+
+== NAME
+MigrateAccountPatchReviewDb - Migrates account patch review db from one database
+backend to another.
+
+== SYNOPSIS
+[verse]
+--
+_java_ -jar gerrit.war MigrateAccountPatchReviewDb
+  -d <SITE_PATH>
+  [--sourceUrl] [--chunkSize]
+--
+
+== DESCRIPTION
+Migrates AccountPatchReviewDb from one database backend to another. The
+AccountPatchReviewDb is a database used to store the user file reviewed flags.
+
+This task is only intended to be run if the configuration parameter
+link:config-gerrit.html#accountPatchReviewDb.url[accountPatchReviewDb.url]
+is set or changed.
+
+To migrate AccountPatchReviewDb:
+
+* Stop Gerrit
+* Configure new value for link:config-gerrit.html#accountPatchReviewDb.url[accountPatchReviewDb.url]
+* Migrate data using this task
+* Start Gerrit
+
+== OPTIONS
+
+-d::
+--sourceUrl::
+	Url of source database. Only need to be specified if the source is not H2.
+
+--chunkSize::
+	Chunk size of fetching from source and pushing to target on each time.
+	Defaults to 100000.
+
+== CONTEXT
+This command can only be run on a server which has direct
+connectivity to the database.
+
+== EXAMPLES
+To migrate from H2 to the database specified by
+link:config-gerrit.html#accountPatchReviewDb.url[accountPatchReviewDb.url]
+in gerrit.config:
+
+----
+	$ java -jar gerrit.war MigrateAccountPatchReviewDb
+----
+
+== SEE ALSO
+
+* Configuration parameter link:config-gerrit.html#accountPatchReviewDb.url[accountPatchReviewDb.url]
+
+GERRIT
+------
+Part of link:index.html[Gerrit Code Review]
+
+SEARCHBOX
+---------
diff --git a/Documentation/pgm-index.txt b/Documentation/pgm-index.txt
index 0c347f4..d61cc0b 100644
--- a/Documentation/pgm-index.txt
+++ b/Documentation/pgm-index.txt
@@ -41,6 +41,9 @@
 link:pgm-LocalUsernamesToLowerCase.html[LocalUsernamesToLowerCase]::
 	Convert the local username of every account to lower case.
 
+link:pgm-MigrateAccountPatchReviewDb.html[MigrateAccountPatchReviewDb]::
+	Migrates AccountPatchReviewDb from one database backend to another.
+
 GERRIT
 ------
 Part of link:index.html[Gerrit Code Review]
diff --git a/gerrit-pgm/src/main/java/com/google/gerrit/pgm/Daemon.java b/gerrit-pgm/src/main/java/com/google/gerrit/pgm/Daemon.java
index 09fe5a3..3af1397 100644
--- a/gerrit-pgm/src/main/java/com/google/gerrit/pgm/Daemon.java
+++ b/gerrit-pgm/src/main/java/com/google/gerrit/pgm/Daemon.java
@@ -74,6 +74,7 @@
 import com.google.gerrit.server.plugins.PluginRestApiModule;
 import com.google.gerrit.server.schema.DataSourceProvider;
 import com.google.gerrit.server.schema.H2AccountPatchReviewStore;
+import com.google.gerrit.server.schema.JdbcAccountPatchReviewStore;
 import com.google.gerrit.server.schema.SchemaVersionCheck;
 import com.google.gerrit.server.securestore.DefaultSecureStore;
 import com.google.gerrit.server.securestore.SecureStore;
@@ -346,7 +347,7 @@
     modules.add(new EventBroker.Module());
     modules.add(test
         ? new H2AccountPatchReviewStore.InMemoryModule()
-        : new H2AccountPatchReviewStore.Module());
+        : new JdbcAccountPatchReviewStore.Module(config));
     modules.add(new ReceiveCommitsExecutorModule());
     modules.add(new DiffExecutorModule());
     modules.add(new MimeUtil2Module());
diff --git a/gerrit-pgm/src/main/java/com/google/gerrit/pgm/MigrateAccountPatchReviewDb.java b/gerrit-pgm/src/main/java/com/google/gerrit/pgm/MigrateAccountPatchReviewDb.java
new file mode 100644
index 0000000..8de7bea
--- /dev/null
+++ b/gerrit-pgm/src/main/java/com/google/gerrit/pgm/MigrateAccountPatchReviewDb.java
@@ -0,0 +1,150 @@
+// Copyright (C) 2017 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.pgm;
+
+import com.google.auto.value.AutoValue;
+import com.google.common.base.Strings;
+import com.google.gerrit.pgm.util.SiteProgram;
+import com.google.gerrit.server.config.GerritServerConfig;
+import com.google.gerrit.server.config.SitePaths;
+import com.google.gerrit.server.schema.DataSourceProvider;
+import com.google.gerrit.server.schema.JdbcAccountPatchReviewStore;
+import com.google.inject.Injector;
+import com.google.inject.Key;
+
+import org.eclipse.jgit.lib.Config;
+import org.kohsuke.args4j.Option;
+
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.ArrayList;
+import java.util.List;
+
+/** Migrates AccountPatchReviewDb from one to another */
+public class MigrateAccountPatchReviewDb extends SiteProgram {
+
+  @Option(name = "--sourceUrl", usage = "Url of source database")
+  private String sourceUrl;
+
+  @Option(name = "--chunkSize", usage = "chunk size of fetching from source and push to target on each time")
+  private static long chunkSize = 100000;
+
+  @Override
+  public int run() throws Exception {
+    SitePaths sitePaths = new SitePaths(getSitePath());
+    Config fakeCfg = new Config();
+    if (!Strings.isNullOrEmpty(sourceUrl)) {
+      System.out.println("source Url (custom): " + sourceUrl);
+      fakeCfg.setString("accountPatchReviewDb", null, "url", sourceUrl);
+    }
+    JdbcAccountPatchReviewStore sourceJdbcAccountPatchReviewStore =
+        JdbcAccountPatchReviewStore.createAccountPatchReviewStore(fakeCfg,
+            sitePaths);
+
+    Injector dbInjector = createDbInjector(DataSourceProvider.Context.SINGLE_USER);
+    Config cfg = dbInjector.getInstance(Key.get(Config.class, GerritServerConfig.class));
+    String targetUrl = cfg.getString("accountPatchReviewDb", null, "url");
+    if (targetUrl == null) {
+      System.err.println("accountPatchReviewDb.url is null in gerrit.config");
+      return 1;
+    }
+    System.out.println("target Url: " + targetUrl);
+    JdbcAccountPatchReviewStore targetJdbcAccountPatchReviewStore =
+        JdbcAccountPatchReviewStore.createAccountPatchReviewStore(cfg, sitePaths);
+    targetJdbcAccountPatchReviewStore.createTableIfNotExists();
+
+    if (!isTargetTableEmpty(targetJdbcAccountPatchReviewStore)) {
+      System.err.println("target table is not empty, cannot proceed");
+      return 1;
+    }
+
+    try (Connection sourceCon = sourceJdbcAccountPatchReviewStore.getConnection();
+        Connection targetCon = targetJdbcAccountPatchReviewStore.getConnection();
+        PreparedStatement sourceStmt =
+            sourceCon.prepareStatement(
+                "SELECT account_id, change_id, patch_set_id, file_name "
+                    + "FROM account_patch_reviews "
+                    + "LIMIT ? "
+                    + "OFFSET ?");
+        PreparedStatement targetStmt =
+            targetCon.prepareStatement("INSERT INTO account_patch_reviews "
+                + "(account_id, change_id, patch_set_id, file_name) VALUES "
+                + "(?, ?, ?, ?)")) {
+      targetCon.setAutoCommit(false);
+      long offset = 0;
+      List<Row> rows = selectRows(sourceStmt, offset);
+      while (!rows.isEmpty()) {
+        insertRows(targetCon, targetStmt, rows);
+        offset += rows.size();
+        rows = selectRows(sourceStmt, offset);
+      }
+    }
+    return 0;
+  }
+
+  @AutoValue
+  abstract static class Row {
+    abstract int accountId();
+    abstract int changeId();
+    abstract int patchSetId();
+    abstract String fileName();
+  }
+
+  private static boolean isTargetTableEmpty(JdbcAccountPatchReviewStore store)
+      throws SQLException {
+    try (Connection con = store.getConnection();
+        Statement s = con.createStatement();
+        ResultSet r = s.executeQuery(
+            "SELECT COUNT(1) FROM account_patch_reviews")) {
+      if (r.next()) {
+        return r.getInt(1) == 0;
+      }
+      return true;
+    }
+  }
+
+  private static List<Row> selectRows(PreparedStatement stmt, long offset)
+      throws SQLException {
+    List<Row> results = new ArrayList<>();
+    stmt.setLong(1, chunkSize);
+    stmt.setLong(2, offset);
+    try (ResultSet rs = stmt.executeQuery()) {
+      while (rs.next()) {
+        results.add(new AutoValue_MigrateAccountPatchReviewDb_Row(
+            rs.getInt("account_id"),
+            rs.getInt("change_id"),
+            rs.getInt("patch_set_id"),
+            rs.getString("file_name")));
+      }
+    }
+    return results;
+  }
+
+  private static void insertRows(Connection con, PreparedStatement stmt,
+      List<Row> rows) throws SQLException {
+    for (Row r : rows) {
+      stmt.setLong(1, r.accountId());
+      stmt.setLong(2, r.changeId());
+      stmt.setLong(3, r.patchSetId());
+      stmt.setString(4, r.fileName());
+      stmt.addBatch();
+    }
+    stmt.executeBatch();
+    con.commit();
+  }
+}
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/schema/H2AccountPatchReviewStore.java b/gerrit-server/src/main/java/com/google/gerrit/server/schema/H2AccountPatchReviewStore.java
index 6dbe916..d07115c 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/schema/H2AccountPatchReviewStore.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/schema/H2AccountPatchReviewStore.java
@@ -15,14 +15,8 @@
 package com.google.gerrit.server.schema;
 
 import com.google.common.annotations.VisibleForTesting;
-import com.google.common.base.Optional;
-import com.google.common.collect.ImmutableSet;
-import com.google.common.primitives.Ints;
-import com.google.gerrit.extensions.events.LifecycleListener;
 import com.google.gerrit.extensions.registration.DynamicItem;
 import com.google.gerrit.lifecycle.LifecycleModule;
-import com.google.gerrit.reviewdb.client.Account;
-import com.google.gerrit.reviewdb.client.PatchSet;
 import com.google.gerrit.server.change.AccountPatchReviewStore;
 import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.config.SitePaths;
@@ -31,35 +25,12 @@
 import com.google.inject.Inject;
 import com.google.inject.Singleton;
 
-import org.apache.commons.dbcp.BasicDataSource;
 import org.eclipse.jgit.lib.Config;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
-import java.sql.Connection;
-import java.sql.DriverManager;
-import java.sql.PreparedStatement;
-import java.sql.ResultSet;
 import java.sql.SQLException;
-import java.sql.Statement;
-import java.util.Collection;
-
-import javax.sql.DataSource;
 
 @Singleton
-public class H2AccountPatchReviewStore
-    implements AccountPatchReviewStore, LifecycleListener {
-  private static final Logger log =
-      LoggerFactory.getLogger(H2AccountPatchReviewStore.class);
-
-  public static class Module extends LifecycleModule {
-    @Override
-    protected void configure() {
-      DynamicItem.bind(binder(), AccountPatchReviewStore.class)
-          .to(H2AccountPatchReviewStore.class);
-      listener().to(H2AccountPatchReviewStore.class);
-    }
-  }
+public class H2AccountPatchReviewStore extends JdbcAccountPatchReviewStore {
 
   @VisibleForTesting
   public static class InMemoryModule extends LifecycleModule {
@@ -72,16 +43,10 @@
     }
   }
 
-  private final DataSource ds;
-
   @Inject
   H2AccountPatchReviewStore(@GerritServerConfig Config cfg,
       SitePaths sitePaths) {
-    this.ds = createDataSource(H2.appendUrlOptions(cfg, getUrl(sitePaths)));
-  }
-
-  public static String getUrl(SitePaths sitePaths) {
-    return H2.createUrl(sitePaths.db_dir.resolve("account_patch_reviews"));
+    super(cfg, sitePaths);
   }
 
   /**
@@ -93,196 +58,11 @@
     // DB_CLOSE_DELAY=-1: By default the content of an in-memory H2 database is
     // lost at the moment the last connection is closed. This option keeps the
     // content as long as the vm lives.
-    this.ds = createDataSource(
-        "jdbc:h2:mem:account_patch_reviews;DB_CLOSE_DELAY=-1");
-  }
-
-  private static DataSource createDataSource(String url) {
-    BasicDataSource datasource = new BasicDataSource();
-    datasource.setDriverClassName("org.h2.Driver");
-    datasource.setUrl(url);
-    datasource.setMaxActive(50);
-    datasource.setMinIdle(4);
-    datasource.setMaxIdle(16);
-    long evictIdleTimeMs = 1000 * 60;
-    datasource.setMinEvictableIdleTimeMillis(evictIdleTimeMs);
-    datasource.setTimeBetweenEvictionRunsMillis(evictIdleTimeMs / 2);
-    return datasource;
+    super(createDataSource("jdbc:h2:mem:account_patch_reviews;DB_CLOSE_DELAY=-1"));
   }
 
   @Override
-  public void start() {
-    try {
-      createTableIfNotExists();
-    } catch (OrmException e) {
-      log.error("Failed to create table to store account patch reviews", e);
-    }
-  }
-
-  public static void createTableIfNotExists(String url) throws OrmException {
-    try (Connection con = DriverManager.getConnection(url);
-        Statement stmt = con.createStatement()) {
-      doCreateTable(stmt);
-    } catch (SQLException e) {
-      throw convertError("create", e);
-    }
-  }
-
-  private void createTableIfNotExists() throws OrmException {
-    try (Connection con = ds.getConnection();
-        Statement stmt = con.createStatement()) {
-      doCreateTable(stmt);
-    } catch (SQLException e) {
-      throw convertError("create", e);
-    }
-  }
-
-  private static void doCreateTable(Statement stmt) throws SQLException {
-    stmt.executeUpdate(
-        "CREATE TABLE IF NOT EXISTS account_patch_reviews ("
-            + "account_id INTEGER DEFAULT 0 NOT NULL, "
-            + "change_id INTEGER DEFAULT 0 NOT NULL, "
-            + "patch_set_id INTEGER DEFAULT 0 NOT NULL, "
-            + "file_name VARCHAR(4096) DEFAULT '' NOT NULL, "
-            + "CONSTRAINT primary_key_account_patch_reviews "
-            + "PRIMARY KEY (account_id, change_id, patch_set_id, file_name)"
-            + ")");
-  }
-
-  public static void dropTableIfExists(String url) throws OrmException {
-    try (Connection con = DriverManager.getConnection(url);
-        Statement stmt = con.createStatement()) {
-      stmt.executeUpdate("DROP TABLE IF EXISTS account_patch_reviews");
-    } catch (SQLException e) {
-      throw convertError("create", e);
-    }
-  }
-
-  @Override
-  public void stop() {
-  }
-
-  @Override
-  public boolean markReviewed(PatchSet.Id psId, Account.Id accountId,
-      String path) throws OrmException {
-    try (Connection con = ds.getConnection();
-        PreparedStatement stmt =
-            con.prepareStatement("INSERT INTO account_patch_reviews "
-                + "(account_id, change_id, patch_set_id, file_name) VALUES "
-                + "(?, ?, ?, ?)")) {
-      stmt.setInt(1, accountId.get());
-      stmt.setInt(2, psId.getParentKey().get());
-      stmt.setInt(3, psId.get());
-      stmt.setString(4, path);
-      stmt.executeUpdate();
-      return true;
-    } catch (SQLException e) {
-      OrmException ormException = convertError("insert", e);
-      if (ormException instanceof OrmDuplicateKeyException) {
-        return false;
-      }
-      throw ormException;
-    }
-  }
-
-  @Override
-  public void markReviewed(PatchSet.Id psId, Account.Id accountId,
-      Collection<String> paths) throws OrmException {
-    if (paths == null || paths.isEmpty()) {
-      return;
-    }
-
-    try (Connection con = ds.getConnection();
-        PreparedStatement stmt =
-            con.prepareStatement("INSERT INTO account_patch_reviews "
-                + "(account_id, change_id, patch_set_id, file_name) VALUES "
-                + "(?, ?, ?, ?)")) {
-      for (String path : paths) {
-        stmt.setInt(1, accountId.get());
-        stmt.setInt(2, psId.getParentKey().get());
-        stmt.setInt(3, psId.get());
-        stmt.setString(4, path);
-        stmt.addBatch();
-      }
-      stmt.executeBatch();
-    } catch (SQLException e) {
-      OrmException ormException = convertError("insert", e);
-      if (ormException instanceof OrmDuplicateKeyException) {
-        return;
-      }
-      throw ormException;
-    }
-  }
-
-  @Override
-  public void clearReviewed(PatchSet.Id psId, Account.Id accountId, String path)
-      throws OrmException {
-    try (Connection con = ds.getConnection();
-        PreparedStatement stmt =
-            con.prepareStatement("DELETE FROM account_patch_reviews "
-                + "WHERE account_id = ? AND change_id = ? AND "
-                + "patch_set_id = ? AND file_name = ?")) {
-      stmt.setInt(1, accountId.get());
-      stmt.setInt(2, psId.getParentKey().get());
-      stmt.setInt(3, psId.get());
-      stmt.setString(4, path);
-      stmt.executeUpdate();
-    } catch (SQLException e) {
-      throw convertError("delete", e);
-    }
-  }
-
-  @Override
-  public void clearReviewed(PatchSet.Id psId) throws OrmException {
-    try (Connection con = ds.getConnection();
-        PreparedStatement stmt =
-            con.prepareStatement("DELETE FROM account_patch_reviews "
-                + "WHERE change_id = ? AND patch_set_id = ?")) {
-      stmt.setInt(1, psId.getParentKey().get());
-      stmt.setInt(2, psId.get());
-      stmt.executeUpdate();
-    } catch (SQLException e) {
-      throw convertError("delete", e);
-    }
-  }
-
-  @Override
-  public Optional<PatchSetWithReviewedFiles> findReviewed(PatchSet.Id psId,
-      Account.Id accountId) throws OrmException {
-    try (Connection con = ds.getConnection();
-        PreparedStatement stmt =
-            con.prepareStatement(
-                "SELECT patch_set_id, file_name FROM account_patch_reviews APR1 "
-                    + "WHERE account_id = ? AND change_id = ? AND patch_set_id = "
-                    + "(SELECT MAX(patch_set_id) FROM account_patch_reviews APR2 WHERE "
-                    + "APR1.account_id = APR2.account_id "
-                    + "AND APR1.change_id = APR2.change_id "
-                    + "AND patch_set_id <= ?)")) {
-      stmt.setInt(1, accountId.get());
-      stmt.setInt(2, psId.getParentKey().get());
-      stmt.setInt(3, psId.get());
-      try (ResultSet rs = stmt.executeQuery()) {
-        if (rs.next()) {
-          PatchSet.Id id = new PatchSet.Id(psId.getParentKey(),
-              rs.getInt("PATCH_SET_ID"));
-          ImmutableSet.Builder<String> builder = ImmutableSet.builder();
-          do {
-            builder.add(rs.getString("FILE_NAME"));
-          } while (rs.next());
-
-          return Optional.of(
-              AccountPatchReviewStore.PatchSetWithReviewedFiles.create(
-                  id, builder.build()));
-        }
-
-        return Optional.absent();
-      }
-    } catch (SQLException e) {
-      throw convertError("select", e);
-    }
-  }
-
-  public static OrmException convertError(String op, SQLException err) {
+  public OrmException convertError(String op, SQLException err) {
     switch (getSQLStateInt(err)) {
       case 23001: // UNIQUE CONSTRAINT VIOLATION
       case 23505: // DUPLICATE_KEY_1
@@ -295,23 +75,4 @@
         return new OrmException(op + " failure on account_patch_reviews", err);
     }
   }
-
-  private static String getSQLState(SQLException err) {
-    String ec;
-    SQLException next = err;
-    do {
-      ec = next.getSQLState();
-      next = next.getNextException();
-    } while (ec == null && next != null);
-    return ec;
-  }
-
-  private static int getSQLStateInt(SQLException err) {
-    String s = getSQLState(err);
-    if (s != null) {
-      Integer i = Ints.tryParse(s);
-      return i != null ? i : -1;
-    }
-    return 0;
-  }
 }
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/schema/JdbcAccountPatchReviewStore.java b/gerrit-server/src/main/java/com/google/gerrit/server/schema/JdbcAccountPatchReviewStore.java
new file mode 100644
index 0000000..c537f9e
--- /dev/null
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/schema/JdbcAccountPatchReviewStore.java
@@ -0,0 +1,325 @@
+// Copyright (C) 2016 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.Optional;
+import com.google.common.collect.ImmutableSet;
+import com.google.common.primitives.Ints;
+import com.google.gerrit.extensions.events.LifecycleListener;
+import com.google.gerrit.extensions.registration.DynamicItem;
+import com.google.gerrit.lifecycle.LifecycleModule;
+import com.google.gerrit.reviewdb.client.Account;
+import com.google.gerrit.reviewdb.client.PatchSet;
+import com.google.gerrit.server.change.AccountPatchReviewStore;
+import com.google.gerrit.server.config.GerritServerConfig;
+import com.google.gerrit.server.config.SitePaths;
+import com.google.gwtorm.server.OrmDuplicateKeyException;
+import com.google.gwtorm.server.OrmException;
+
+import org.apache.commons.dbcp.BasicDataSource;
+import org.eclipse.jgit.lib.Config;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.Collection;
+
+import javax.sql.DataSource;
+
+public abstract class JdbcAccountPatchReviewStore
+    implements AccountPatchReviewStore, LifecycleListener {
+  private static final Logger log =
+      LoggerFactory.getLogger(JdbcAccountPatchReviewStore.class);
+
+  public static class Module extends LifecycleModule {
+    private final Config cfg;
+
+    public Module(Config cfg) {
+      this.cfg = cfg;
+    }
+
+    @Override
+    protected void configure() {
+      String url = cfg.getString("accountPatchReviewDb", null, "url");
+      if (url == null || url.contains("h2")) {
+        DynamicItem.bind(binder(), AccountPatchReviewStore.class)
+            .to(H2AccountPatchReviewStore.class);
+        listener().to(H2AccountPatchReviewStore.class);
+      } else if (url.contains("postgresql")) {
+        DynamicItem.bind(binder(), AccountPatchReviewStore.class)
+            .to(PostgresqlAccountPatchReviewStore.class);
+        listener().to(PostgresqlAccountPatchReviewStore.class);
+      } else if (url.contains("mysql")) {
+        DynamicItem.bind(binder(), AccountPatchReviewStore.class)
+            .to(MysqlAccountPatchReviewStore.class);
+        listener().to(MysqlAccountPatchReviewStore.class);
+      } else {
+        throw new IllegalArgumentException(
+            "unsupported driver type for account patch reviews db: " + url);
+      }
+    }
+  }
+
+  private final DataSource ds;
+
+  public static JdbcAccountPatchReviewStore createAccountPatchReviewStore(
+      Config cfg, SitePaths sitePaths) {
+    String url = cfg.getString("accountPatchReviewDb", null, "url");
+    if (url == null || url.contains("h2")) {
+      return new H2AccountPatchReviewStore(cfg, sitePaths);
+    } else if (url.contains("postgresql")) {
+      return new PostgresqlAccountPatchReviewStore(cfg, sitePaths);
+    } else if (url.contains("mysql")) {
+      return new MysqlAccountPatchReviewStore(cfg, sitePaths);
+    } else {
+      throw new IllegalArgumentException(
+          "unsupported driver type for account patch reviews db: " + url);
+    }
+  }
+
+  protected JdbcAccountPatchReviewStore(Config cfg,
+      SitePaths sitePaths) {
+    this.ds = createDataSource(getUrl(cfg, sitePaths));
+  }
+
+  protected JdbcAccountPatchReviewStore(DataSource ds) {
+    this.ds = ds;
+  }
+
+  private static String getUrl(@GerritServerConfig Config cfg,
+      SitePaths sitePaths) {
+    String url = cfg.getString("accountPatchReviewDb", null, "url");
+    if (url == null) {
+      return H2.createUrl(sitePaths.db_dir.resolve("account_patch_reviews"));
+    }
+    return url;
+  }
+
+  protected static DataSource createDataSource(String url) {
+    BasicDataSource datasource = new BasicDataSource();
+    if (url.contains("postgresql")) {
+      datasource.setDriverClassName("org.postgresql.Driver");
+    } else if (url.contains("h2")) {
+      datasource.setDriverClassName("org.h2.Driver");
+    } else if (url.contains("mysql")) {
+      datasource.setDriverClassName("com.mysql.jdbc.Driver");
+    }
+    datasource.setUrl(url);
+    datasource.setMaxActive(50);
+    datasource.setMinIdle(4);
+    datasource.setMaxIdle(16);
+    long evictIdleTimeMs = 1000 * 60;
+    datasource.setMinEvictableIdleTimeMillis(evictIdleTimeMs);
+    datasource.setTimeBetweenEvictionRunsMillis(evictIdleTimeMs / 2);
+    return datasource;
+  }
+
+  @Override
+  public void start() {
+    try {
+      createTableIfNotExists();
+    } catch (OrmException e) {
+      log.error("Failed to create table to store account patch reviews", e);
+    }
+  }
+
+  public Connection getConnection() throws SQLException {
+    return ds.getConnection();
+  }
+
+  public void createTableIfNotExists() throws OrmException {
+    try (Connection con = ds.getConnection();
+        Statement stmt = con.createStatement()) {
+      doCreateTable(stmt);
+    } catch (SQLException e) {
+      throw convertError("create", e);
+    }
+  }
+
+  private static void doCreateTable(Statement stmt) throws SQLException {
+    stmt.executeUpdate(
+        "CREATE TABLE IF NOT EXISTS account_patch_reviews ("
+            + "account_id INTEGER DEFAULT 0 NOT NULL, "
+            + "change_id INTEGER DEFAULT 0 NOT NULL, "
+            + "patch_set_id INTEGER DEFAULT 0 NOT NULL, "
+            + "file_name VARCHAR(4096) DEFAULT '' NOT NULL, "
+            + "CONSTRAINT primary_key_account_patch_reviews "
+            + "PRIMARY KEY (account_id, change_id, patch_set_id, file_name)"
+            + ")");
+  }
+
+  public void dropTableIfExists() throws OrmException {
+    try (Connection con = ds.getConnection();
+        Statement stmt = con.createStatement()) {
+      stmt.executeUpdate("DROP TABLE IF EXISTS account_patch_reviews");
+    } catch (SQLException e) {
+      throw convertError("create", e);
+    }
+  }
+
+  @Override
+  public void stop() {
+  }
+
+  @Override
+  public boolean markReviewed(PatchSet.Id psId, Account.Id accountId,
+      String path) throws OrmException {
+    try (Connection con = ds.getConnection();
+        PreparedStatement stmt =
+            con.prepareStatement("INSERT INTO account_patch_reviews "
+                + "(account_id, change_id, patch_set_id, file_name) VALUES "
+                + "(?, ?, ?, ?)")) {
+      stmt.setInt(1, accountId.get());
+      stmt.setInt(2, psId.getParentKey().get());
+      stmt.setInt(3, psId.get());
+      stmt.setString(4, path);
+      stmt.executeUpdate();
+      return true;
+    } catch (SQLException e) {
+      OrmException ormException = convertError("insert", e);
+      if (ormException instanceof OrmDuplicateKeyException) {
+        return false;
+      }
+      throw ormException;
+    }
+  }
+
+  @Override
+  public void markReviewed(PatchSet.Id psId, Account.Id accountId,
+      Collection<String> paths) throws OrmException {
+    if (paths == null || paths.isEmpty()) {
+      return;
+    }
+
+    try (Connection con = ds.getConnection();
+        PreparedStatement stmt =
+            con.prepareStatement("INSERT INTO account_patch_reviews "
+                + "(account_id, change_id, patch_set_id, file_name) VALUES "
+                + "(?, ?, ?, ?)")) {
+      for (String path : paths) {
+        stmt.setInt(1, accountId.get());
+        stmt.setInt(2, psId.getParentKey().get());
+        stmt.setInt(3, psId.get());
+        stmt.setString(4, path);
+        stmt.addBatch();
+      }
+      stmt.executeBatch();
+    } catch (SQLException e) {
+      OrmException ormException = convertError("insert", e);
+      if (ormException instanceof OrmDuplicateKeyException) {
+        return;
+      }
+      throw ormException;
+    }
+  }
+
+  @Override
+  public void clearReviewed(PatchSet.Id psId, Account.Id accountId, String path)
+      throws OrmException {
+    try (Connection con = ds.getConnection();
+        PreparedStatement stmt =
+            con.prepareStatement("DELETE FROM account_patch_reviews "
+                + "WHERE account_id = ? AND change_id = ? AND "
+                + "patch_set_id = ? AND file_name = ?")) {
+      stmt.setInt(1, accountId.get());
+      stmt.setInt(2, psId.getParentKey().get());
+      stmt.setInt(3, psId.get());
+      stmt.setString(4, path);
+      stmt.executeUpdate();
+    } catch (SQLException e) {
+      throw convertError("delete", e);
+    }
+  }
+
+  @Override
+  public void clearReviewed(PatchSet.Id psId) throws OrmException {
+    try (Connection con = ds.getConnection();
+        PreparedStatement stmt =
+            con.prepareStatement("DELETE FROM account_patch_reviews "
+                + "WHERE change_id = ? AND patch_set_id = ?")) {
+      stmt.setInt(1, psId.getParentKey().get());
+      stmt.setInt(2, psId.get());
+      stmt.executeUpdate();
+    } catch (SQLException e) {
+      throw convertError("delete", e);
+    }
+  }
+
+  @Override
+  public Optional<PatchSetWithReviewedFiles> findReviewed(PatchSet.Id psId,
+      Account.Id accountId) throws OrmException {
+    try (Connection con = ds.getConnection();
+        PreparedStatement stmt =
+            con.prepareStatement(
+                "SELECT patch_set_id, file_name FROM account_patch_reviews APR1 "
+                    + "WHERE account_id = ? AND change_id = ? AND patch_set_id = "
+                    + "(SELECT MAX(patch_set_id) FROM account_patch_reviews APR2 WHERE "
+                    + "APR1.account_id = APR2.account_id "
+                    + "AND APR1.change_id = APR2.change_id "
+                    + "AND patch_set_id <= ?)")) {
+      stmt.setInt(1, accountId.get());
+      stmt.setInt(2, psId.getParentKey().get());
+      stmt.setInt(3, psId.get());
+      try (ResultSet rs = stmt.executeQuery()) {
+        if (rs.next()) {
+          PatchSet.Id id = new PatchSet.Id(psId.getParentKey(),
+              rs.getInt("patch_set_id"));
+          ImmutableSet.Builder<String> builder = ImmutableSet.builder();
+          do {
+            builder.add(rs.getString("file_name"));
+          } while (rs.next());
+
+          return Optional.of(
+              AccountPatchReviewStore.PatchSetWithReviewedFiles.create(
+                  id, builder.build()));
+        }
+
+        return Optional.absent();
+      }
+    } catch (SQLException e) {
+      throw convertError("select", e);
+    }
+  }
+
+  public OrmException convertError(String op, SQLException err) {
+    if (err.getCause() == null && err.getNextException() != null) {
+      err.initCause(err.getNextException());
+    }
+    return new OrmException(op + " failure on account_patch_reviews", err);
+  }
+
+  private static String getSQLState(SQLException err) {
+    String ec;
+    SQLException next = err;
+    do {
+      ec = next.getSQLState();
+      next = next.getNextException();
+    } while (ec == null && next != null);
+    return ec;
+  }
+
+  protected static int getSQLStateInt(SQLException err) {
+    String s = getSQLState(err);
+    if (s != null) {
+      Integer i = Ints.tryParse(s);
+      return i != null ? i : -1;
+    }
+    return 0;
+  }
+}
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/schema/MysqlAccountPatchReviewStore.java b/gerrit-server/src/main/java/com/google/gerrit/server/schema/MysqlAccountPatchReviewStore.java
new file mode 100644
index 0000000..7cf28ff
--- /dev/null
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/schema/MysqlAccountPatchReviewStore.java
@@ -0,0 +1,53 @@
+// Copyright (C) 2017 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.gerrit.server.config.GerritServerConfig;
+import com.google.gerrit.server.config.SitePaths;
+import com.google.gwtorm.server.OrmDuplicateKeyException;
+import com.google.gwtorm.server.OrmException;
+import com.google.inject.Inject;
+import com.google.inject.Singleton;
+
+import org.eclipse.jgit.lib.Config;
+
+import java.sql.SQLException;
+
+@Singleton
+public class MysqlAccountPatchReviewStore extends JdbcAccountPatchReviewStore {
+
+  @Inject
+  MysqlAccountPatchReviewStore(@GerritServerConfig Config cfg,
+      SitePaths sitePaths) {
+    super(cfg, sitePaths);
+  }
+
+  @Override
+  public OrmException convertError(String op, SQLException err) {
+    switch (getSQLStateInt(err)) {
+      case 1022: // ER_DUP_KEY
+      case 1062: // ER_DUP_ENTRY
+      case 1169: // ER_DUP_UNIQUE;
+        return new OrmDuplicateKeyException("ACCOUNT_PATCH_REVIEWS", err);
+
+
+      default:
+        if (err.getCause() == null && err.getNextException() != null) {
+          err.initCause(err.getNextException());
+        }
+        return new OrmException(op + " failure on ACCOUNT_PATCH_REVIEWS", err);
+    }
+  }
+}
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/schema/PostgresqlAccountPatchReviewStore.java b/gerrit-server/src/main/java/com/google/gerrit/server/schema/PostgresqlAccountPatchReviewStore.java
new file mode 100644
index 0000000..c264c68
--- /dev/null
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/schema/PostgresqlAccountPatchReviewStore.java
@@ -0,0 +1,54 @@
+// Copyright (C) 2017 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.gerrit.server.config.GerritServerConfig;
+import com.google.gerrit.server.config.SitePaths;
+import com.google.gwtorm.server.OrmDuplicateKeyException;
+import com.google.gwtorm.server.OrmException;
+import com.google.inject.Inject;
+import com.google.inject.Singleton;
+
+import org.eclipse.jgit.lib.Config;
+
+import java.sql.SQLException;
+
+@Singleton
+public class PostgresqlAccountPatchReviewStore extends JdbcAccountPatchReviewStore {
+
+  @Inject
+  PostgresqlAccountPatchReviewStore(@GerritServerConfig Config cfg,
+      SitePaths sitePaths) {
+    super(cfg, sitePaths);
+  }
+
+  @Override
+  public OrmException convertError(String op, SQLException err) {
+    switch (getSQLStateInt(err)) {
+      case 23505: // DUPLICATE_KEY_1
+        return new OrmDuplicateKeyException("ACCOUNT_PATCH_REVIEWS", err);
+
+      case 23514: // CHECK CONSTRAINT VIOLATION
+      case 23503: // FOREIGN KEY CONSTRAINT VIOLATION
+      case 23502: // NOT NULL CONSTRAINT VIOLATION
+      case 23001: // RESTRICT VIOLATION
+      default:
+        if (err.getCause() == null && err.getNextException() != null) {
+          err.initCause(err.getNextException());
+        }
+        return new OrmException(op + " failure on ACCOUNT_PATCH_REVIEWS", err);
+    }
+  }
+}
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/schema/SchemaUpdater.java b/gerrit-server/src/main/java/com/google/gerrit/server/schema/SchemaUpdater.java
index 0b7e8b0..24022e9 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/schema/SchemaUpdater.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/schema/SchemaUpdater.java
@@ -22,6 +22,7 @@
 import com.google.gerrit.server.config.AllProjectsName;
 import com.google.gerrit.server.config.AllUsersName;
 import com.google.gerrit.server.config.AnonymousCowardName;
+import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.config.SitePaths;
 import com.google.gerrit.server.git.GitRepositoryManager;
 import com.google.gwtorm.server.OrmException;
@@ -35,6 +36,7 @@
 import com.google.inject.Stage;
 
 import org.eclipse.jgit.errors.ConfigInvalidException;
+import org.eclipse.jgit.lib.Config;
 import org.eclipse.jgit.lib.PersonIdent;
 
 import java.io.IOException;
@@ -71,6 +73,7 @@
         for (Key<?> k : new Key<?>[]{
             Key.get(PersonIdent.class, GerritPersonIdent.class),
             Key.get(String.class, AnonymousCowardName.class),
+            Key.get(Config.class, GerritServerConfig.class),
             }) {
           rebind(parent, k);
         }
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/schema/Schema_127.java b/gerrit-server/src/main/java/com/google/gerrit/server/schema/Schema_127.java
index 783cce6..cc2b0b2 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/schema/Schema_127.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/schema/Schema_127.java
@@ -15,13 +15,15 @@
 package com.google.gerrit.server.schema;
 
 import com.google.gerrit.reviewdb.server.ReviewDb;
+import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.config.SitePaths;
 import com.google.gwtorm.server.OrmException;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
 
+import org.eclipse.jgit.lib.Config;
+
 import java.sql.Connection;
-import java.sql.DriverManager;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;
@@ -31,19 +33,24 @@
   private static final int MAX_BATCH_SIZE = 1000;
 
   private final SitePaths sitePaths;
+  private final Config cfg;
 
   @Inject
-  Schema_127(Provider<Schema_126> prior, SitePaths sitePaths) {
+  Schema_127(Provider<Schema_126> prior,
+      SitePaths sitePaths,
+      @GerritServerConfig Config cfg) {
     super(prior);
     this.sitePaths = sitePaths;
+    this.cfg = cfg;
   }
 
   @Override
   protected void migrateData(ReviewDb db, UpdateUI ui) throws OrmException {
-    String url = H2AccountPatchReviewStore.getUrl(sitePaths);
-    H2AccountPatchReviewStore.dropTableIfExists(url);
-    H2AccountPatchReviewStore.createTableIfNotExists(url);
-    try (Connection con = DriverManager.getConnection(url);
+    JdbcAccountPatchReviewStore jdbcAccountPatchReviewStore =
+        JdbcAccountPatchReviewStore.createAccountPatchReviewStore(cfg, sitePaths);
+    jdbcAccountPatchReviewStore.dropTableIfExists();
+    jdbcAccountPatchReviewStore.createTableIfNotExists();
+    try (Connection con = jdbcAccountPatchReviewStore.getConnection();
         PreparedStatement stmt =
             con.prepareStatement("INSERT INTO account_patch_reviews "
                 + "(account_id, change_id, patch_set_id, file_name) VALUES "
@@ -69,7 +76,7 @@
         stmt.executeBatch();
       }
     } catch (SQLException e) {
-      throw H2AccountPatchReviewStore.convertError("insert", e);
+      throw jdbcAccountPatchReviewStore.convertError("insert", e);
     }
   }
 }
diff --git a/gerrit-war/src/main/java/com/google/gerrit/httpd/WebAppInitializer.java b/gerrit-war/src/main/java/com/google/gerrit/httpd/WebAppInitializer.java
index 16a699b..1120e0d 100644
--- a/gerrit-war/src/main/java/com/google/gerrit/httpd/WebAppInitializer.java
+++ b/gerrit-war/src/main/java/com/google/gerrit/httpd/WebAppInitializer.java
@@ -61,7 +61,7 @@
 import com.google.gerrit.server.schema.DataSourceProvider;
 import com.google.gerrit.server.schema.DataSourceType;
 import com.google.gerrit.server.schema.DatabaseModule;
-import com.google.gerrit.server.schema.H2AccountPatchReviewStore;
+import com.google.gerrit.server.schema.JdbcAccountPatchReviewStore;
 import com.google.gerrit.server.schema.SchemaModule;
 import com.google.gerrit.server.schema.SchemaVersionCheck;
 import com.google.gerrit.server.securestore.SecureStoreClassName;
@@ -298,7 +298,7 @@
     modules.add(new DropWizardMetricMaker.RestModule());
     modules.add(new LogFileCompressor.Module());
     modules.add(new EventBroker.Module());
-    modules.add(new H2AccountPatchReviewStore.Module());
+    modules.add(new JdbcAccountPatchReviewStore.Module(config));
     modules.add(cfgInjector.getInstance(GitRepositoryManagerModule.class));
     modules.add(new StreamEventsApiListener.Module());
     modules.add(new ReceiveCommitsExecutorModule());