RFR: 7164841: Improvements to the GC log file rotation

Yumin Qi yumin.qi at oracle.com
Fri Aug 30 23:36:14 PDT 2013


Hi, all


   With more feedback on the second version, the third version make 
following changes:

   1) take parametrized filename after -Xloggc:, the filename will be 
forced to follow following rules:
       can only contain [A-Z][a-z][0-9].-_%[p|t], any other character 
used for file name will be rejected. %p or %t can only appear once in 
file name.
       example:  -Xloggc:test.log-%t-%p           OK
       example: -Xloggc:test.log-%p-%p           FAIL

    2) removed unused rotatingFileStream constructors

    3) log more information at head of rotation file:
        vm version, os version, build id etc
        memory usage
        commandline  flags

    Tested on Linux/Windows

    URL: http://cr.openjdk.java.net/~minqi/7164841/webrev0 
<http://cr.openjdk.java.net/%7Eminqi/7164841/webrev0>2

   Thanks
   Yumin

On 8/21/2013 3:43 PM, Yumin Qi wrote:
> Hi, all
>
>   This is second version after feedback from first round.
>   The changes are:
>
>   1) file name will be based on gc log file name (-Xloggc:filename), 
> pid (process id) and time when the first rotation file created:
>        <filename>-pid<pid>-YYYY-MM-DD_HH-MM-SS
>   2) If rotate in same file, file name is as in 1), if rotate in 
> multiple files, .<i> will append to above file name.
>   3) every time file rotated, file name and time when file created 
> will be logged to head/tail, this is same as first version.
>   4) current file has name 
> <filename>-pid<pid>-YYYY-MM-DD_HH-MM-SS.<i>.current
>        This is similar to first version.
>        By adapting such name format we will never loss logs in case 
> apps stops and restart, the log files will not be overwritten since 
> time stamp in file names.
>    5) If open file failed, turn off gc log rotation.
>         If due to some reason, file operation failed (such as 
> permission changed etc), with log file opened, logging still works, 
> but at
>         saving and renaming, the file operation will fail, this will 
> lead not all files saved.
>
> http://cr.openjdk.java.net/~minqi/7164841/webrev01
>
>      Tested with jtreg, JPRT.
>
> Thanks
> Yumin
>
> On 8/15/2013 8:35 AM, Yumin Qi wrote:
>> Hi,
>>
>>   Can I have your review for this small changes?
>> http://cr.openjdk.java.net/~minqi/7164841/webrev00/ 
>> <http://cr.openjdk.java.net/%7Eminqi/7164841/webrev00/>
>>
>>    This is for a enhancement to add head/tail message to the logging 
>> files to assist reading GC output.
>>    1. modified prompt message if invalid arguments used for log rotating;
>>    2. add time and file name message to log file head/tail.
>>    3. for easily identify which log file is current, use file name 
>> like <filename>.n.current, after it reaches maximum size, rename it 
>> to <filename>.n
>>         On Windows, there is no F_OK (existing test) definition, F_OK 
>> is defined as "0" and for _access of VC++, it just describes:
>>
>> modevalue
>>
>> 	
>>
>> Checks file for
>>
>> 00
>>
>> 	
>>
>> Existence only
>>
>> 02
>>
>> 	
>>
>> Write-only
>>
>> 04
>>
>> 	
>>
>> Read-only
>>
>> 06
>>
>> 	
>>
>> Read and write
>>
>>
>> http://msdn.microsoft.com/en-us/library/1w06ktdy.aspx
>> The definition are consistent with unistd.h.
>>
>>     Test: JPRT and jtreg.
>>
>>    Thanks
>>    Yumin
>

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