Re: Handling large files with Emacs

[Jambunathan K <kjambunathan@gmail.com>]

Tom <adatgyujto@gmail.com> writes:

> Eli Zaretskii <eliz <at> gnu.org> writes:
>
>> 
>> That's ridiculously small.  I routinely edit files approaching 500MB
>> without any problems, and that's on a 32-bit machine, whereas yours is
>> a 64-bit one.  So something is seriously wrong with your system, or
>> maybe with the Emacs binary (but I can hardly believe it).
>> 
>> 
>
> I think it's because syntax highlight or something. When I try opening
> SQL dumps (say, 200MB) then Emacs grinds to a halt for a minute or
> so, and moving in the file is very slow even after that.

Have you experimented with `font-lock-maximum-size' together with
`font-lock-support-mode'?

,----[ C-h v font-lock-maximum-size RET ]
| font-lock-maximum-size is a variable defined in `font-lock.el'.
| Its value is 256000
| 
|   This variable is obsolete since 24.1.
| 
| Documentation:
| Maximum buffer size for unsupported buffer fontification.
| When `font-lock-support-mode' is nil, only buffers smaller than
| this are fontified.  This variable has no effect if a Font Lock
| support mode (usually `jit-lock-mode') is enabled.
| 
| If nil, means size is irrelevant.
| If a list, each element should be a cons pair of the form (MAJOR-MODE . SIZE),
| where MAJOR-MODE is a symbol or t (meaning the default).  For example:
|  ((c-mode . 256000) (c++-mode . 256000) (rmail-mode . 1048576))
| means that the maximum size is 250K for buffers in C or C++ modes, one megabyte
| for buffers in Rmail mode, and size is irrelevant otherwise.
| 
| You can customize this variable.
| 
| [back]
`----

>
> If I don't use an .sql extension, so that the file is not opened
> in SQL mode then it's much better. So opening big files in fundamental
> mode works well, but if it has its own mode with syntax highlighting
> then it's pretty much unusable.
>
> I think Fab has a similar problem, because he opens the big file
> in Bibtex mode which also does it's own stuff, parsing the buffer
> with regexps for syntax highlighting, or something like this.
>
>
>

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