我正在尝试为一个项目在 Android 和 iOS 中的 SQLite 性能之间执行基准测试，并且与 Android 相比，在 iOS 平台上的性能似乎非常差。
我想要实现的是测量将多行（5000）插入 SQLite DB 并在平台之间进行比较的时间。对于 Android，执行所有 5000 次插入需要大约 500 毫秒的结果，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 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 sec\n", [startTime timeIntervalSinceNow]]];
//END: INSERT BENCHMARK
安卓代码片段：
// 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