[jira] [Commented] (HBASE-5954) Allow proper fsync support for HBase

["Lars Hofhansl (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-5954?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14222246#comment-14222246 ] 

Lars Hofhansl commented on HBASE-5954:
--------------------------------------

Looking at trunk this is a whole lot more complicated now. We need to keep two highest sequence numbers now, one for a normal sync (i.e. hflush) and fsync (i.e. hsync). The SyncFutures have to carry an fsync flag. And if FSLog.SyncRunner.run() need to keep track of two sequence numbers as well. As well as the logic to release other futures in the queue... Looks pretty tricky to merge this in.


> Allow proper fsync support for HBase
> ------------------------------------
>
>                 Key: HBASE-5954
>                 URL: https://issues.apache.org/jira/browse/HBASE-5954
>             Project: HBase
>          Issue Type: Improvement
>          Components: HFile, wal
>            Reporter: Lars Hofhansl
>            Assignee: Lars Hofhansl
>            Priority: Critical
>             Fix For: 2.0.0
>
>         Attachments: 5954-trunk-hdfs-trunk-v2.txt, 5954-trunk-hdfs-trunk-v3.txt, 5954-trunk-hdfs-trunk-v4.txt, 5954-trunk-hdfs-trunk-v5.txt, 5954-trunk-hdfs-trunk-v6.txt, 5954-trunk-hdfs-trunk.txt, hbase-hdfs-744.txt
>
>
> At least get recommendation into 0.96 doc and some numbers running w/ this hdfs feature enabled.



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