Pool/share file channels for HDFS read --------------------------------------
Key: HDFS-1323 URL: https://issues.apache.org/jira/browse/HDFS-1323 Project: Hadoop HDFS Issue Type: Improvement Components: data-node Reporter: Jay Booth Fix For: 0.20-append, 0.22.0 Currently, all reads in HDFS require opening and closing the underlying block/meta filechannels. We could pool these filechannels and save some system calls and other work. Since HDFS read requests can be satisfied by positioned reads and transferTos, we can even share these filechannels between concurrently executing requests. The attached patch was benchmarked as part of work on HDFS-918 and exhibited a 10% performance increase for small random reads. This does not affect client logic and involves minimal change to server logic. Patch is based on branch 20-append. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.