[ http://issues.apache.org/jira/browse/HADOOP-803?page=comments#action_12458638 ] Raghu Angadi commented on HADOOP-803: -------------------------------------
> I do not see how replacing TreeSet=TreeMap<Block, static final Object> by > TreeMap<Block, Block> in DatanodeDescriptor > would reduce memory consumption. This does not reduce memory .This will let us get hold of original object that was inserted in to the map. That fact that all nodes that have a particular block and blockMap reference the same object reduces memory. Now we have 1 Block object instead of 4 (in the case of 3 replicas). This references argument might be flawed since I am kind of new to Java. > Block getBlock( Block b) > looks very strange. So you need a block in order to get it .......... :). We could call it getStoredBloc() or getBlock(BlockId). We want a function that gives the Block object what was stored in the map. > Reducing memory consumption on Namenode : Part 1 > ------------------------------------------------ > > Key: HADOOP-803 > URL: http://issues.apache.org/jira/browse/HADOOP-803 > Project: Hadoop > Issue Type: Bug > Reporter: Raghu Angadi > Assigned To: Raghu Angadi > Attachments: block-refs-2.patch, block-refs.patch > > > There appears to be some places in Namenode that allow reducing memory > consumption without intrusive code or feature changes. This bug is an initial > attempt making those changes. Please include your thoughts as well. > One change I am planning to make : > Currently one copy of each block exists for each of the replicas and one copy > for blockMap. I think they are all supposed to be same. -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira
