[MAPREDUCE-6626] Reuse ObjectMapper instance in MapReduce

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 2.7.1
• Fix Version/s: 2.8.0, 3.0.0-alpha1
• Component/s: performance
• Hadoop Flags: Reviewed
• Assignee: Yiqun Lin
• Reporter: Yiqun Lin
• Created: 03/Feb/16 06:05
• Updated: 30/Aug/16 01:14
• Resolved: 09/Feb/16 18:06

Description

Now in MapReduce, there are some places creating a new ObjectMapper instance every time. In wiki of ObjectMapper, it suggested:

Further: it is beneficial to use just one instance (or small number of instances) for data binding; many optimizations for reuse (of symbol tables, some buffers) depend on ObjectMapper instances being reused. 

http://webcache.googleusercontent.com/search?q=cache:kybMTIJC6F4J:wiki.fasterxml.com/JacksonFAQ+&cd=4&hl=ja&ct=clnk&gl=jp, it's similar to HDFS-9724.

Issue Links

• is related to: HDFS-9768 Reuse objectMapper instance in HDFS to improve the performance
• is related to: YARN-4668 Reuse objectMapper instance in Yarn