ChangeLog

2012-09-06  Joshua Bell  <jsbell@chromium.org>

        IndexedDB: IDBFactory.deleteDatabase() is slow

        https://bugs.webkit.org/show_bug.cgi?id=96036

        Reviewed by NOBODY (OOPS!).

        The deleteDatabase() operation is implemented by creating a LevelDBTansaction to accumulate

        the records to delete, then committing it. The transaction is a tree of key/operation pairs.

        As each (key, delete) entry is added to the tree compares need to be made, potentially

        requiring full key decodes. Since this temporary transaction is never read from, this is

        overkill.

        Instead, expose a new LevelDB::removeRange() method that only creates a LevelDBWriteBatch.

        This is lighter weight than a LevelDBTransaction, has transactional integrity, and appears

        faster than calling into leveldb to remove each individual record directly.

        No new tests - no functional changes, only perf improvement.

        * Modules/indexeddb/IDBLevelDBBackingStore.cpp:

        (WebCore::IDBLevelDBBackingStore::deleteDatabase):

        * platform/leveldb/LevelDBDatabase.cpp:

        (WebCore::LevelDBDatabase::removeRange):

        (WebCore):

        * platform/leveldb/LevelDBDatabase.h:

        (LevelDBDatabase):

2012-09-03  Sam Weinig  <sam@webkit.org>

        Part 1 of removing PlatformString.h, move remaining functions to new homes

Source/WebCore/Modules/indexeddb/IDBLevelDBBackingStore.cpp

@@static bool deleteRange(LevelDBTransaction* transaction, const Vector<char>& beg

bool IDBLevelDBBackingStore::deleteDatabase(const String& name)

{

    IDB_TRACE("IDBLevelDBBackingStore::deleteDatabase");

363 RefPtr<LevelDBTransaction> transaction = LevelDBTransaction::create(m_db.get());

    int64_t databaseId;

    String version;

    int64_t intVersion;

    if (!getIDBDatabaseMetaData(name, version, intVersion, databaseId)) {

369 transaction->rollback();

        return true;

    }

    const Vector<char> startKey = DatabaseMetaDataKey::encode(databaseId, DatabaseMetaDataKey::OriginName);

    const Vector<char> stopKey = DatabaseMetaDataKey::encode(databaseId + 1, DatabaseMetaDataKey::OriginName);

375 if (!deleteRange(transaction.get(), startKey, stopKey)) {

376 transaction->rollback();

373 if (!m_db->removeRange(startKey, stopKey)) {

        return false;

    }

    const Vector<char> key = DatabaseNameKey::encode(m_identifier, name);

    transaction->remove(key);

    return transaction->commit();

378 return m_db->remove(key);

}

static bool checkObjectStoreAndMetaDataType(const LevelDBIterator* it, const Vector<char>& stopKey, int64_t objectStoreId, int64_t metaDataType)

Source/WebCore/platform/leveldb/LevelDBDatabase.cpp

@@bool LevelDBDatabase::remove(const LevelDBSlice& key)

    return false;

}

bool LevelDBDatabase::removeRange(const LevelDBSlice& start, const LevelDBSlice& limit)

{

    OwnPtr<LevelDBIterator> it = createIterator();

    OwnPtr<LevelDBWriteBatch> writeBatch = LevelDBWriteBatch::create();

    for (it->seek(start); it->isValid() && m_comparator->compare(it->key(), limit) < 0; it->next())

        writeBatch->remove(it->key());

    leveldb::WriteOptions writeOptions;

    writeOptions.sync = true;

    const leveldb::Status s = m_db->Write(writeOptions, writeBatch->m_writeBatch.get());

    if (s.ok())

        return true;

    LOG_ERROR("LevelDB write failed: %s", s.ToString().c_str());

    return false;

}

bool LevelDBDatabase::get(const LevelDBSlice& key, Vector<char>& value)

{

    std::string result;

Source/WebCore/platform/leveldb/LevelDBDatabase.h

@@public:

    bool put(const LevelDBSlice& key, const Vector<char>& value);

    bool remove(const LevelDBSlice& key);

58 bool removeRange(const LevelDBSlice& start, const LevelDBSlice& limit);

    bool get(const LevelDBSlice& key, Vector<char>& value);

    bool write(LevelDBWriteBatch&);

    PassOwnPtr<LevelDBIterator> createIterator();