[TAJO-1093] DateTimeFormat.to_char() is slower than SimpleDateFormat.format()

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 0.9.0
• Component/s: Data Type
• Labels: datetime
• Assignee: Jihun Kang
• Reporter: Hyoungjun Kim
• Created: 02/Oct/14 10:15
• Updated: 15/Oct/14 09:35
• Resolved: 07/Oct/14 03:35

Description

I tested DateTimeFormat class with the below code.

TimeMeta tm = new TimeMeta();
DateTimeUtil.toJulianTimeMeta(DateTimeUtil.javaTimeToJulianTime(System.currentTimeMillis()), tm);

int iteration = 1000000;
long startTime = System.currentTimeMillis();
for (int i = 0; i < iteration; i++) {
  DateTimeFormat.to_char(tm, "YYYY-MM-DD HH24:MI:SS");
}
long endTime = System.currentTimeMillis();
System.out.println("DateTimeFormat.to_char: " + (endTime - startTime) + " ms");

///////////////////////////////////////////////////////////
SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
Date date = new Date();
startTime = System.currentTimeMillis();
for (int i = 0; i < iteration; i++) {
  df.format(date);
}
endTime = System.currentTimeMillis();
System.out.println("SimpleDateFormat.format: " + (endTime - startTime) + " ms");

///////////////////////////////////////////////////////////
startTime = System.currentTimeMillis();
for (int i = 0; i < iteration; i++) {
  DateTimeFormat.parseDateTime("2014-01-01 12:11:11", "YYYY-MM-DD HH24:MI:SS");
}
endTime = System.currentTimeMillis();
System.out.println("DateTimeFormat.parseDateTime: " + (endTime - startTime) + " ms");

///////////////////////////////////////////////////////////
startTime = System.currentTimeMillis();
for (int i = 0; i < iteration; i++) {
  df.parse("2014-01-01 12:11:11");
}
endTime = System.currentTimeMillis();
System.out.println("SimpleDateFormat.parse: " + (endTime - startTime) + " ms");

The following is the test result. DateTimeFormat.to_char is 20 times slower than SimpleDateFormat.format.

DateTimeFormat.to_char: 6993 ms
SimpleDateFormat.format: 373 ms
DateTimeFormat.parseDateTime: 798 ms
SimpleDateFormat.parse: 1400 ms