Android Sqlite Performance

问题

I have been doing some experiments to measure sqlite performance on android. I was disappointed a little bit with the results. What i did was inserting 10.000 queries to table and it took 130-140 seconds but with these conditions;

1. Samsung galaxy s3 in power saving mode

2. Inserted data(or class)has 3 strings and one float(real for sqlite)

3. Insert event is being done in asynctask.

4. In asynctask, i am showing a progress dialog with passed timer text in it (System.currentTimeMillis - seconds etc blala)

class AddStudentsTask extends AsyncTask<Void,Integer,Void>
{
    ProgressDialog prgDialog;
    int max = 10000;
    Student s;
    long seconds = System.currentTimeMillis();


    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        prgDialog = new ProgressDialog(MainActivity.this);
        prgDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
        prgDialog.setMessage(seconds+"");
        prgDialog.setMax(max);
        prgDialog.setCancelable(false);
        prgDialog.show();

    }

    @Override
    protected void onProgressUpdate(Integer... values) {
        super.onProgressUpdate();
        prgDialog.setProgress(values[0]);
        sList.add(s);
        String s = (System.currentTimeMillis()-seconds)/100+"";
        if(s.length()>2)
            s = s.substring(0,s.length()-1) + "." + s.charAt(s.length()-1);
        else if(s.length() == 2)
            s = s.charAt(0) + "." + s.charAt(1);
        prgDialog.setMessage(s + " seconds passed.");

    }

    @Override
    protected Void doInBackground(Void... voids) {

        for(int a = 0;a< max; a++ )
        {
            Random r = new Random();
            s = new Student();

            s.setGpa(r.nextFloat()*4);
            s.setLastName("asdasd");
            s.setFirstName("Oh My God");
            s.setAddress("1sadasd");
            s.setId(sda.insert(s));
            publishProgress(a);
        }

        return null;
    }

    @Override
    protected void onPostExecute(Void aVoid) {
        super.onPostExecute(aVoid);
        prgDialog.dismiss();
        sa.notifyDataSetChanged();
    }
}

5. I am using contentValues with insertOrThrow method in helperdb class. THIS IS OLD SLOW CODE

public long insert(Student s)
{
    SQLiteDatabase db = sh.getWritableDatabase();
    ContentValues cv = new ContentValues();
    cv.put(StudentHelper.FIRSTNAME,s.getFirstName());
    cv.put(StudentHelper.LASTNAME,s.getLastName());
    cv.put(StudentHelper.ADDRESS,s.getAddress());
    cv.put(StudentHelper.GPA,s.getGpa());
    s.setId(db.insertOrThrow(StudentHelper.TABLE_NAME, null, cv));
    return s.getId();
}

6. This task is done in onCreate method of activity.

So what am i doing wrong here or expecting too much from it? Are these results ok or bad?

What can i do to improve my code?

EDIT

So i changed my insert code to this and it reduced to 4.5 seconds!!!

public ArrayList<Long> insertMany(ArrayList<Student> stus)
{
    ArrayList<Long> ids = new ArrayList();
    String sql = "INSERT INTO "+StudentHelper.TABLE_NAME+"" +
            "("+StudentHelper.FIRSTNAME+","+StudentHelper.LASTNAME+"," +
            " "+StudentHelper.GPA+") values(?,?,?)";
    SQLiteDatabase db = sh.getWritableDatabase();
    db.beginTransaction();

    for(Student s:stus) {
        SQLiteStatement stmt = db.compileStatement(sql);

        stmt.bindString(1, s.getFirstName());
        stmt.bindString(2, s.getLastName());
        stmt.bindDouble(3, s.getGpa());

        s.setId(stmt.executeInsert());
        ids.add(s.getId());
        stmt.clearBindings();
    }

    db.setTransactionSuccessful();
    db.endTransaction();

    return ids;
}

回答1:

Use SQLite transaction for speed up

Use BEGIN TRANSACTION & END TRANSACTION for SQLite Optimization

Each SQL statement is enclosed in a new transaction block by SQLite runtime, by default. Sowhen you perform a basic DB operation such as INSERT, a transaction block will be created and wrapped around it.

Letting SQLite runtime manage the transaction for you is advisable only if your routine performs only one DB operation on a data set. However, if you are doing numerous DB operations (say INSERT inside for loop), this becomes very expensive, since it requires reopening, writing to, and closing the journal file for each statement. You may refer

Android SQLite database: slow insertion
http://www.androidcode.ninja/android-sqlite-transaction-tutorial/
http://www.techrepublic.com/blog/software-engineer/turbocharge-your-sqlite-inserts-on-android/
http://www.android-app-market.com/sqlite-optimization-in-android-programming-sqlite-optimization-in-android-apps.html

回答2:

You can use SQL transactions in Android like this. It's better to insert multiple rows into database in larger batches then making single commit (write into SQLlite datafile which is very slow) for every inserted row.

public void insert(List<Student> students)
{
    SQLiteDatabase db = sh.getWritableDatabase();
    ContentValues cv = new ContentValues();

    db.beginTransaction();

    try {
        for (Student s : students) {
                cv.put(StudentHelper.FIRSTNAME,s.getFirstName());
                cv.put(StudentHelper.LASTNAME,s.getLastName());
                cv.put(StudentHelper.ADDRESS,s.getAddress());
                cv.put(StudentHelper.GPA,s.getGpa());

                db.insertOrThrow(StudentHelper.TABLE_NAME, null, cv)
        }
        setTransactionSuccessful();
    } finally {
         db.endTransaction();
    }
}

回答3:

Well, you have so many records and for every record you call getWritableDatabase() and then insert it, which is bad for performance.

You need to use transactions. Look at this question Android SQLite database: slow insertion. Basically you need to call beginTransaction(), do your insertions and then call setTransactionSuccessful() preceded by endTransaction(). You will be amazed to see how much performance gain you will get with this.

来源：https://stackoverflow.com/questions/28188164/android-sqlite-performance

标签

android

android-asynctask

android-sqlite