[HIVE-17998] Use FastDateFormat instead of SimpleDateFormat for TimestampWritable

• Type: Improvement
• Status: Resolved
• Priority: Trivial
• Resolution: Duplicate
• Affects Version/s: 2.4.0, 3.0.0
• Component/s: Serializers/Deserializers
• Flags: Patch
• Assignee: David Mollitor
• Reporter: David Mollitor
• Created: 07/Nov/17 16:01
• Updated: 08/Nov/17 18:09
• Resolved: 08/Nov/17 15:03

Description

Currently Hive is using this ThreadLocal/SimpleDateFormat setup to work around the thread-safety limitations of SimpleDateFormat.

Let us simply drink the Apache Commons champagne and use thread-safe org.apache.commons.lang.time.FastDateFormat instead.

org.apache.hadoop.hive.serde2.io.TimestampWritable

  private static final ThreadLocal<DateFormat> threadLocalDateFormat =
      new ThreadLocal<DateFormat>() {
        @Override
        protected DateFormat initialValue() {
          return new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        }
      };

Issue Links

• duplicates: HIVE-17417 LazySimple Timestamp is very expensive