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Erik Rozendaal commented on HBASE-2180: --------------------------------------- I saw both CLOSE_WAIT and TIME_WAIT. Maybe CLOSE_WAIT was in the majority. Connections were mostly to the data node. $ uname -a Linux inrdb-worker1.ripe.net 2.6.18-164.11.1.el5 #1 SMP Wed Jan 20 07:32:21 EST 2010 x86_64 x86_64 x86_64 GNU/Linux They do go after a while, since after a few of the "Cannot assign requested address" exceptions the server starts working again. Unfortunately I'll be away for the weekend and won't be able to investigate further. I wonder why so many connections are being opened so quickly that the server runs out of ports within a few minutes of starting the gets/puts? > Bad random read performance from synchronizing hfile.fddatainputstream > ---------------------------------------------------------------------- > > Key: HBASE-2180 > URL: https://issues.apache.org/jira/browse/HBASE-2180 > Project: Hadoop HBase > Issue Type: Bug > Reporter: ryan rawson > Assignee: stack > Fix For: 0.20.4, 0.21.0 > > Attachments: 2180-v2.patch, 2180.patch > > > deep in the HFile read path, there is this code: > synchronized (in) { > in.seek(pos); > ret = in.read(b, off, n); > } > this makes it so that only 1 read per file per thread is active. this > prevents the OS and hardware from being able to do IO scheduling by > optimizing lots of concurrent reads. > We need to either use a reentrant API (pread may be partially reentrant > according to Todd) or use multiple stream objects, 1 per scanner/thread. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.