The meaning of "ordered-by-time" field in a file format

[piotr-dobrogost]

From https://lnav.readthedocs.io/en/latest/formats.html#defining-a-new-format (emphasis mine):

ordered-by-time:
(v0.8.3+) Indicates that the order of messages in the file is time-based. Files that are not naturally ordered by time will be sorted in order to display them in the correct order. Note that this sorting can incur a performance penalty when tailing logs.

Does it mean that a file is treated as unordered (not naturally ordered) thus needs to be sorted unless ordered-by-time for this file is set to true? If so then shouldn't most default file formats have this flag set?

[tstack]

The default for this flag is true, sorry that's not clear.

[piotr-dobrogost]

Thanks for info. I would suggest adding this information do the docs.