Many of time, we need to count the total number of blocks in a datanode by calling DatanodeDescriptor#numBlocks(). It has to traverse the block list to get the counter, which may not be trivial if there are millions of blocks. Adding a counter for each datanode does not cost much space but help save CPU processing time.
|Status||Open [ 1 ]||Patch Available [ 10002 ]|
|Status||Patch Available [ 10002 ]||Resolved [ 5 ]|
|Resolution||Fixed [ 1 ]|
|Status||Resolved [ 5 ]||Closed [ 6 ]|