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https://issues.apache.org/jira/browse/KAFKA-1646?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14179731#comment-14179731
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xueqiang wang commented on KAFKA-1646:
--------------------------------------

Hey, Jay, sorry for late. I have done a test and find there is no pause when 
rolling new log segment. The time for creating an 1G file and 1K file is almost 
identical: all about 1ms.
Here is the test code which creating 10 files of 1G:
    public static void main(String[] args) throws Exception  {
        String filePre = "d:\\temp\\file";
        long startTime, elapsedTime;
        startTime = System.currentTimeMillis();
        try {
            long initFileSize = 1024000000l;
            for (int i = 0; i < 10; i++) {
                RandomAccessFile randomAccessFile = new 
RandomAccessFile(filePre + i, "rw");
                randomAccessFile.setLength(initFileSize);
                randomAccessFile.getChannel();
            }
            elapsedTime = System.currentTimeMillis() - startTime;
            System.out.format("elapsedTime: %2d ms", elapsedTime);
        } catch (Exception exception) { }
    }

The result is: elapsedTime: 14 ms


> Improve consumer read performance for Windows
> ---------------------------------------------
>
>                 Key: KAFKA-1646
>                 URL: https://issues.apache.org/jira/browse/KAFKA-1646
>             Project: Kafka
>          Issue Type: Improvement
>          Components: log
>    Affects Versions: 0.8.1.1
>         Environment: Windows
>            Reporter: xueqiang wang
>              Labels: newbie, patch
>         Attachments: Improve consumer read performance for Windows.patch, 
> KAFKA-1646-truncate-off-trailing-zeros-on-broker-restart-if-bro.patch
>
>
> This patch is for Window platform only. In Windows platform, if there are 
> more than one replicas writing to disk, the segment log files will not be 
> consistent in disk and then consumer reading performance will be dropped down 
> greatly. This fix allocates more disk spaces when rolling a new segment, and 
> then it will improve the consumer reading performance in NTFS file system.
> This patch doesn't affect file allocation of other filesystems, for it only 
> adds statements like 'if(Os.iswindow)' or adds methods used on Windows.



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