Re: [PROPOSAL] Shared Ispell dictionaries

On Wed, Mar 07, 2018 at 01:02:07PM +0100, Pavel Stehule wrote:
> > Understand. I'm not againts the mmap() approach, just I have lack of
> > understanding mmap() benefits... Current shared Ispell approach requires
> > preprocessing after server restarting, and the main advantage of mmap()
> > here
> > is that mmap() doesn't require preprocessing after restarting.
> >
> > Speaking about the implementation.
> >
> > It seems that the most appropriate place to store preprocessed files is
> > 'pg_dynshmem' folder. File prefix could be 'ts_dict.', otherwise
> > dsm_cleanup_for_mmap() will remove them.
> >
> > I'm not sure about reusing dsm_impl_mmap() and dsm_impl_windows(). But
> > maybe it's worth to reuse them.
> >
>
> I don't think so serialization to file (mmap) has not too sense. But the
> shared dictionary should loaded every time, and should be released every
> time if it is possible.Maybe there can be some background worker, that
> holds dictionary in memory.

Do you mean that a shared dictionary should be reloaded if its .affix
and .dict files was changed? IMHO we can store last modification
timestamp of them in a preprocessed file, and then we can rebuild the
dictionary if files was changed.

--
Arthur Zakirov
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Russian Postgres Company