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https://issues.apache.org/jira/browse/LOG4J2-3457?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17515220#comment-17515220
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Piotr Karwasz commented on LOG4J2-3457:
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[~PoojaTheCoder],
Remark, that acquiring a file lock for each log message is already implemented
in Log4j2's {{FileAppender}} (cf. [locking
parameter|https://logging.apache.org/log4j/2.x/manual/appenders.html#FileAppender]).
The lack of the same option in the {{RollingFileAppender}} can be definitely
addressed, since it is just a configuration problem. By a rudimentary
benchmark, with this feature on your throughput is decreased 2x.
I don't understand what's the "*.roll" file purpose in your code, since it does
not appear to be created anywhere. I believe you don't need this feature for
time-based triggering policies (when you use these policies log files are never
renamed). For size-based triggering policies you might reimplement your
appender by creating a custom {{SizeBasedTriggeringPolicy}} that reads the real
size of the file from time to time (Log4j2 never does that, it triggers
rollovers based on the amount of bytes it wrote to the file) and does something
to prevent multiple applications from rolling over at the same time. That will
cost you even more performance.
Personally I wouldn't bother implementing such a complex feature and I would
use a {{SyslogAppender}} (or {{FlumeAppender}}) and delegate the writing of the
log files to those applications.
> Log4j 1.x 2.17.2 bridge - Does standard RollingFileAppender supports multiple
> process writing to same log file at the same time??
> ---------------------------------------------------------------------------------------------------------------------------------
>
> Key: LOG4J2-3457
> URL: https://issues.apache.org/jira/browse/LOG4J2-3457
> Project: Log4j 2
> Issue Type: Question
> Components: Log4j 1.2 bridge
> Affects Versions: 2.17.2
> Reporter: Pooja Pandey
> Assignee: Piotr Karwasz
> Priority: Major
> Attachments:
> CitedText-RollingFileAppenderNoSupportForMultProcessWritingToSameFile.PNG,
> CustomLogger.java, CustomLoggerFactory.java,
> CustomMultiProcessRollingAppender.java, JavaLoggingMultiThTest.java,
> customlog.properties
>
>
> In our application we require a rolling file appender which can be used
> across multiple processes targeting the same file.
> I wanted to check if current log4j1.x 2.17.2 bridge version supports multi
> process rolling file appender, if not then is there any plan to support this
> feature in future releases??
> For reference, as per our application requirement, I am attaching sample java
> class files for custom appender, custom multi process rolling appender,
> sample test program with multiple threads for which we can run multiple
> instances to test multi process rolling and log4j property
> file.[^CustomLogger.java][^JavaLoggingMultiThTest.java][^customlog.properties]
>
> In one of the mail chain to group Log4J Users List
> <log4j-u...@logging.apache.org>, [~ralphgoers] pointed out that
> {color:#ff0000}_"FWIW the Log4j 2 RollingFileAppender does not support being
> used across multiple processes targeting the same file either. I’d love to
> know how you avoided having the file roll multiple times (once for each
> process)"_{color}.
> !CitedText-RollingFileAppenderNoSupportForMultProcessWritingToSameFile.PNG|width=756,height=434!
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