FileChannel doesn't flush to disk on unix until close

[sdaly2107]

Expected behavior

When FileChannel flushing is disabled, the contents should still be written to disk eventually without flushing after every write.

Actual behavior

On Windows this works fine, but on Linux the contents are not flushed until I close the channel. Opening and closing the channel for every message or enabling flushing does not give us the performance we require.

Steps to reproduce the problem

-Create FileChannel with flush false. Log some messages, wait several ms and check file on disk.
-Messages should be in the file
-On Windows this is working fine, but on Linux the file is empty. Closing the channel OR enabling flushing makes this work, however I expect this to work with flushing disabled and without having to close the channel.

POCO version

1.7.9

Compiler and version

gcc 7.3.0

Operating system and version

Ubuntu 18.04

Other relevant information

[sdaly2107]

From what I can tell, on Linux the LogFile is a FileOutputStream. Enabling flushing fixes this and doesn't hurt performance - think in this case though that means flushing the FileOutputStream and not necessarily to disk.

Without flushing:
100 writes = around 3ms on Windows
100 writes = around 8ms on Linux (NO content until channel closed)

With flushing:
100 writes = around 106ms on Windows
100 writes = around 9ms on Linux - Content OK

Since we don't need flushing, one workaround is to enable flushing for Linux.

[github-actions]

This issue is stale because it has been open for 365 days with no activity.

[github-actions]

This issue is stale because it has been open for 365 days with no activity.