Android和iOS上的SQLite之间的性能差异

我试图在Android和iOS中为项目执行SQLite性能之间的基准测试,并且与Android相比,iOS平台上的性能似乎非常糟糕.

我想要实现的是测量将多个行(5000)插入SQLite DB并在平台之间进行比较的时间.对于Android,我得到大约500ms的结果来执行所有5000次插入,但对于iOS,相同的操作需要20秒以上.怎么会这样？

这是我的iOS代码片段(插入部分),dataArray是一个包含5000个随机100个字符NSStrings的数组：

int numEntries = 5000;
self.dataArray = [[NSMutableArray alloc] initWithCapacity:numEntries];//Array for random data to write to database

//generate random data (100 char strings)
for (int i=0; i<numEntries; i++) {
    [self.dataArray addObject:[self genRandStringLength:100]];
}

// Get the documents directory
NSArray *dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

NSString *docsDir = [dirPaths objectAtIndex:0];

// Build the path to the database file
NSString *databasePath = [[NSString alloc] initWithString:[docsDir stringByAppendingPathComponent: @"benchmark.db"]];

NSString *resultHolder = @"";

//Try to open DB, if file not present, create it
if (sqlite3_open([databasePath UTF8String], &db) == SQLITE_OK){

    sql = @"CREATE TABLE IF NOT EXISTS BENCHMARK(ID INTEGER PRIMARY KEY AUTOINCREMENT, TESTCOLUMN TEXT)";

    //Create table
    if (sqlite3_exec(db, [sql UTF8String], NULL, NULL, NULL) == SQLITE_OK){
        NSLog(@"DB created");
    }else{
        NSLog(@"Failed to create DB");
    }

        //START: INSERT BENCHMARK
        NSDate *startTime = [[NSDate alloc] init];//Get timestamp for insert-timer

        //Insert values in DB, one by one
        for (int i = 0; i<numEntries; i++) {
            sql = [NSString stringWithFormat:@"INSERT INTO BENCHMARK (TESTCOLUMN) VALUES('%@')",[self.dataArray objectAtIndex:i]];
            if (sqlite3_exec(db, [sql UTF8String], NULL, NULL, NULL) == SQLITE_OK){
                //Insert successful
            }
        }

        //Append time consumption to display string
        resultHolder = [resultHolder stringByAppendingString:[NSString stringWithFormat:@"5000 insert ops took %f secn", [startTime timeIntervalSinceNow]]];

        //END: INSERT BENCHMARK

Android代码段：

           // SETUP
           long startTime, finishTime;

        // Get database object
            BenchmarkOpenHelper databaseHelper = new BenchmarkOpenHelper(getApplicationContext());
            SQLiteDatabase database = databaseHelper.getWritableDatabase();

            // Generate array containing random data
            int rows = 5000;
            String[] rowData = new String[rows];
            int dataLength = 100;

            for (int i=0; i<rows; i++) {
                rowData[i] = generateRandomString(dataLength);
            }

            // FIRST TEST: Insertion
            startTime = System.currentTimeMillis();

            for(int i=0; i<rows; i++) {
                database.rawQuery("INSERT INTO BENCHMARK (TESTCOLUMN) VALUES(?)", new String[] {rowData[i]});
            }

            finishTime = System.currentTimeMillis();
            result += "Insertion test took: " + String.valueOf(finishTime-startTime) + "ms n";
            // END FIRST TEST

解决方法:

您需要使用事务 – 首先执行BEGIN并使用COMMIT结束.

这应该会大大提高INSERT的性能.

http://www.titaniumdevelopment.com.au/blog/2012/01/27/10x-faster-inserts-in-sqlite-using-begin-commit-in-appcelerator-titanium-mobile/

一旦完成,我预计在两个平台上都会有5000个插件非常快.

这是另一个StackOverflow答案,其中列出了大量可以提高SQLite性能的不同内容,包括使用绑定变量和启用各种PRAGMA模式,这些模式可以提高速度的稳健性：Improve INSERT-per-second performance of SQLite?

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