Question

下面的代码从ArrayList获取数据并将其写入设备上的SQLite数据库。它运行速度相当慢，ArrayList大小约为800，大约需要1.5分钟。你看到任何可以使它运行的东西快？

Iterator<PermitData> iterator = permitDataArrayList.iterator();
while (iterator.hasNext()) {
    PermitData permitData = (PermitData) iterator.next();

    HashMap<String, String> queryValues = new HashMap<String, String>();

    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_ID, Integer.toString(permitData.Id));
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_TYPE, permitData.Type);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_NAME, permitData.Name);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_FIELD1, permitData.Field1);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_FIELD2, permitData.Field2);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_FIELD3, permitData.Field3);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_FIELD4, permitData.Field4);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_FIELD5, permitData.Field5);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_FIELD6, permitData.Field6);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_FIELD7, permitData.Field7);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_FIELD8, permitData.Field8);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_FIELD9, permitData.Field9);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_FIELD10, permitData.Field10);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_FIELD11, permitData.Field11);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_FIELD12, permitData.Field12);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_FIELD13, permitData.Field13);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_FIELD14, permitData.Field14);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_FIELD15, permitData.Field15);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_TO_DATE, permitData.ToDate);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_FROM_DATE, permitData.FromDate);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_FIELD16, permitData.Field16);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_FIELD17, permitData.Field17);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_ADDRESS, permitData.Address);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_PHONE, permitData.Phone);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_FIELD18, permitData.Field18);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_EMAIL, permitData.Email);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_FIELD19, permitData.Field19);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_XCOORD, permitData.XCoord);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_YCOORD, permitData.YCoord);
    queryValues.put(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_FIELD20, permitData.Field20);

    try {
        sqLiteManager.insertOrUpdatePermit(PermitDataContract.PermitDataEntry.TABLE_NAME, queryValues);
    }
    catch (Exception e) {
        Log.d("StoreData", " Id: " + queryValues.get(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_ID) + " Name: " + queryValues.get(PermitDataContract.PermitDataEntry.COLUMN_NAME_PERMIT_NAME));
    }

} // end while

SQLiteManager.java

public synchronized void insertOrUpdatePermit(String tableName, HashMap<String, String> queryValues) {

    ContentValues contentValues = new ContentValues();

    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_ID, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_ID));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_TYPE, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_TYPE));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_NAME, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_NAME));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD1, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD1));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD2, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD2));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD3, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD3));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD4, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD4));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD5, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD5));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD6, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD6));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD7, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD7));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD8, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD8));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD9, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD9));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD10, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD10));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD11, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD11));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD12, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD12));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD13, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD13));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD14, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD14));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD15, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD15));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_FROM_DATE, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_FROM_DATE));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_TO_DATE, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_TO_DATE));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD16, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD16));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD17, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD17));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_ADDRESS, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_ADDRESS));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_PHONE, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_PHONE));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD18, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD18));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_EMAIL, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_EMAIL));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD19, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD19));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_XCOORD, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_XCOORD));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_YCOORD, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_YCOORD));
    contentValues.put(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD20, queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_FIELD20));

    String permitId = queryValues.get(PermitDataEntry.COLUMN_NAME_PERMIT_ID);
    String columns[] = {PermitDataEntry.COLUMN_NAME_PERMIT_ID};
    Cursor cursor = null;
    try {
        cursor = mDatabase.query(tableName, columns, PermitDataEntry.COLUMN_NAME_PERMIT_ID + "=?", new String[]{permitId}, null, null, null);
    }
    catch (Exception e) {
        Log.e("insertOrUpdatePermit", "exception:cursor: " + tableName + " columns: " + columns);
        e.printStackTrace();
    }

    // if count is 0, then permitId does not exist, so insert
    // if count is 1, then permitId does exist, so update
    int count = cursor.getCount();
    if (count == 0) { // if new row
        mDatabase.insert(tableName, null, contentValues);
    }
    else { // primary key already exists
        mDatabase.update(tableName, contentValues, null, null);
    }

    cursor.close();
}

Answer 1

默认情况下，SQLite语句的边界（例如insert(), update（）, execSQL（）`）就是单个语句。这意味着您的代码正在进行800次交易。每个事务都涉及磁盘I / O，以更新数据库和事务日志。做很多小事务会变慢。

对于批量数据操作，最好围绕工作包装自己的事务。部分地，这将是速度。部分地，这样整个批量数据加载将整体成功或失败，因此如果它失败（例如，外键约束违规），则不会结合成功和失败的操作。

伪Java用于：

db.beginTransaction();

try {
  // do real SQL calls here
  db.setTransactionSuccesful();
}
finally {
  db.endTransaction();
}

（其中db是SQLiteDatabase，catch块是可选的）

编写SQLite的代码很慢

1 个答案: