Merge pull request #780 from vladak/union_workaround

do not run expensive JDBC query if FILEMOVES table is empty or tracking ...

Author: tarzanek

src/org/opensolaris/opengrok/history/JDBCHistoryCache.java

@@ -18,7 +18,7 @@
  */
 
 /*
- * Copyright (c) 2008, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2014, Oracle and/or its affiliates. All rights reserved.
  */
 
 package org.opensolaris.opengrok.history;
@@ -103,6 +103,9 @@ class JDBCHistoryCache implements HistoryCache {
     private static final PreparedQuery GET_LAST_MODIFIED_TIMES =
             new PreparedQuery(getQuery("getLastModifiedTimes"));
 
+    private static final PreparedQuery GET_FILEMOVES_COUNT =
+            new PreparedQuery(getQuery("getFilemovesCount"));
+
     /**
      * The number of times to retry an operation that failed in a way that
      * indicates that it may succeed if it's tried again.
@@ -516,6 +519,8 @@ private static String truncate(String str, int length) {
      */
     private static final PreparedQuery GET_FILE_HISTORY =
             new PreparedQuery(getQuery("getFileHistory"));
+    private static final PreparedQuery GET_FILE_HISTORY_FOLDED =
+            new PreparedQuery(getQuery("getFileHistoryFolded"));
 
     /**
      * Statement that gets the history for all files matching a pattern in the
@@ -550,6 +555,31 @@ public History get(File file, Repository repository, boolean withFiles)
         }
     }
 
+    /**
+     * Get the number of rows in the FILEMOVES table. This is used as a
+     * workaround/optimization since JavaDB cannot currently handle the
+     * GET_FILE_HISTORY very well.
+     * @return number of rows in the FILEMOVES table
+     * @throws SQLException
+     */
+    private int getFilemovesCount() throws SQLException {
+        final ConnectionResource conn;
+        conn = connectionManager.getConnectionResource();
+
+        try {
+            final PreparedStatement cntPS = conn.getStatement(GET_FILEMOVES_COUNT);
+            try (ResultSet rs = cntPS.executeQuery()) {
+                if (rs.next()) {
+                    return rs.getInt(1);
+                }
+            }
+        } finally {
+            connectionManager.releaseConnection(conn);
+        }
+
+        return -1;
+    }
+
     /**
      * Helper for {@link #get(File, Repository)}.
      */
@@ -561,6 +591,8 @@ private History getHistory(
         final ArrayList<HistoryEntry> entries = new ArrayList<HistoryEntry>();
         final ConnectionResource conn =
                 connectionManager.getConnectionResource();
+        RuntimeEnvironment env = RuntimeEnvironment.getInstance();
+
         try {
             final PreparedStatement ps;
             if (file.isDirectory()) {
@@ -569,7 +601,8 @@ private History getHistory(
                 ps.setString(2, filePath);
             } else {
                 // Fetch history for a single file only.
-                ps = conn.getStatement(GET_FILE_HISTORY);
+                ps = conn.getStatement(env.RenamedFilesEnabled() && (getFilemovesCount() > 0) ?
+                    GET_FILE_HISTORY : GET_FILE_HISTORY_FOLDED);
                 ps.setString(2, getParentPath(filePath));
                 ps.setString(3, getBaseName(filePath));
             }
@@ -609,7 +642,6 @@ private History getHistory(
         History history = new History();
         history.setHistoryEntries(entries);
 
-        RuntimeEnvironment env = RuntimeEnvironment.getInstance();
         if (env.isTagsEnabled() && repository.hasFileBasedTags()) {
             repository.assignTagsInHistory(history);
         }

src/org/opensolaris/opengrok/history/JDBCHistoryCache_queries.properties

@@ -124,6 +124,22 @@ getFileHistory=\
       R.PATH = ? AND D.PATH = ? AND F.NAME = ? \
   ORDER BY CS.ID DESC
 
+getFileHistoryFolded=\
+  SELECT CS.REVISION, A.NAME, CS.TIME, CS.MESSAGE, CS.ID \
+  FROM \
+      OPENGROK.CHANGESETS CS \
+          JOIN OPENGROK.FILECHANGES FC ON CS.ID = FC.CHANGESET \
+          JOIN OPENGROK.FILES F ON FC.FILE = F.ID \
+          JOIN OPENGROK.DIRECTORIES D ON D.ID = F.DIRECTORY \
+          JOIN OPENGROK.AUTHORS A ON A.ID = CS.AUTHOR \
+          JOIN OPENGROK.REPOSITORIES R ON D.REPOSITORY = R.ID \
+  WHERE \
+      R.PATH = ? AND D.PATH = ? AND F.NAME = ? \
+  ORDER BY CS.ID DESC
+
+getFilemovesCount=\
+  SELECT COUNT(*) FROM OPENGROK.FILEMOVES
+
 getDirHistory=\
   SELECT CS.REVISION, A.NAME, CS.TIME, CS.MESSAGE, CS.ID \
   FROM \