Optimize entries in edits log for persistBlocks calls -----------------------------------------------------
Key: HDFS-3023 URL: https://issues.apache.org/jira/browse/HDFS-3023 Project: Hadoop HDFS Issue Type: Improvement Components: name-node, performance Affects Versions: HA branch (HDFS-1623), 0.23.2 Reporter: Todd Lipcon Assignee: Todd Lipcon One of the performance issues noticed in the HA branch is due to the much larger edit logs, now that we are writing OP_ADD transactions to the edit log on every block allocation. We can condense these calls down in two ways: 1) use variable-length integers for the block list length, size, and genstamp (most of these end up fitting in far less than 8 bytes) 2) use delta-coding for the genstamp and block size for any blocks after the first block (most blocks will be the same size and only slightly higher genstamps) 3) introduce a new OP_UPDATE_BLOCKS transaction that doesn't re-serialize metadata information like lease owner, permissions, etc 4) allow OP_UPDATE_BLOCKS to only re-serialize the blocks that have changed for a given transaction -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira