我在插入记录时看到了非常糟糕的表现.
我知道外部存储器可能很慢,但我想看到一些数字,所以我写了一个测试它的小应用程序.

这是代码：

public static final int INSERTS = 100;
 
File dbFile = new File(Environment.getExternalStorageDirectory(),"test.sqlite3");
// File dbFile = new File(getFilesDir(),"test.sqlite3");
dbFile.delete();
 
sqliteDatabase db = sqliteDatabase.openOrCreateDatabase(dbFile,null);
 
db.execsql("CREATE TABLE events (_id integer primary key autoincrement,event_type TEXT NOT NULL,timestamp BIGINT,data TEXT);");
db.execsql("CREATE INDEX mainIndex ON events (event_type,timestamp ASC);");
 
InsertHelper helper = new InsertHelper(db,"events");
 
final int eventTypeCol = helper.getColumnIndex("event_type");
final int timestampCol = helper.getColumnIndex("timestamp");
final int dataCol = helper.getColumnIndex("data");
 
long start = System.currentTimeMillis();
 
String eventType = "foo",data = "bar";
long timestamp = 4711;
 
for(int i = 0; i < INSERTS; ++i) {
    helper.prepareForInsert();
    helper.bind(eventTypeCol,eventType);
    helper.bind(timestampCol,timestamp);
    helper.bind(dataCol,data);
    helper.execute();
}
 
long end = System.currentTimeMillis();
 
Log.i("Test",String.format("InsertHelper,Speed: %d ms,Records per second: %.2f",(int)(end-start),1000*(double)INSERTS/(double)(end-start)));
 
db.close();
dbFile.delete();
 
db = sqliteDatabase.openOrCreateDatabase(dbFile,timestamp ASC);");
 
 
start = System.currentTimeMillis();
ContentValues cv = new ContentValues();
 
for(int i = 0; i < INSERTS; ++i) {
    cv.put("event_type",eventType);
    cv.put("timestamp",timestamp);
    cv.put("data",data);
    db.insert("events",null,cv);
}
 
end = System.currentTimeMillis();
 
Log.i("Test",String.format("Normal,end-start,1000*(double)INSERTS/(double)(end-start)));
 
db.close();
dbFile.delete();

数据库与我的真实应用程序使用的数据库完全一样,我尝试删除索引,但它没有任何区别.

结果如下：

Nexus One,Internal memory
 
      Method | Records | Time (ms) | Records per second
-------------+---------+-----------+--------------------
      Normal |   100   |    2072   |       48.26
InsertHelper |   100   |    1662   |       60.17
 
 
Nexus One,External memory:
 
      Method | Records | Time (ms) | Records per second
-------------+---------+-----------+--------------------
      Normal |   100   |    7390   |       13.53
InsertHelper |   100   |    7152   |       13.98
 
 
Emulator,Internal memory:
 
      Method | Records | Time (ms) | Records per second
-------------+---------+-----------+--------------------
      Normal |   100   |    1803   |       55.46
InsertHelper |   100   |    3075   |       32.52
 
 
Emulator,External memory:
 
      Method | Records | Time (ms) | Records per second
-------------+---------+-----------+--------------------
      Normal |   100   |    5742   |       17.42
InsertHelper |   100   |    7164   |       13.96 
 

正如您所看到的,模拟器不可信任,InsertHelper应该更快.
当然,这是预期的,测试主要是出于好奇.

然而,让我担心的是当我使用外部存储器时手机性能不佳,我是否错过了SQLiteDatabase的一些关键方面,还是只是为了让SD卡变慢？

我可以在我的真实应用程序中添加我已禁用locking并且它没什么区别.