Re: flatcurve index size (10x larger than lucene)

Jean-Daniel Beaubien via dovecot <[email protected]> Mon, 18 May 2026 17:45:16 -0400
Newsgroups gmane.mail.imap.dovecot
Message-ID <CAB962xw1zRqV7H6mz891QjTufwDQmuQn76N4RdLV7gyjZ9FoXw@mail.gmail.com>
Thank you.

Removing substring and revuilding the indexes worked.

The size iscnow similar to lucene, and approx 8x smaller than with
substring emabled.

Speed also seems 20%-30% faster when querying the text or body of email.

Thank you for the help.


On Thu, May 14, 2026, 4:45 p.m. Aki Tuomi <[email protected]>
wrote:

>
> > On 14/05/2026 23:21 EEST Jean-Daniel Beaubien via dovecot <
> [email protected]> wrote:
> >
> >
> > Hi everyone,
> >
> > I am currently trying to update from an old dovecot 2.3 setup with
> > fts-lucene to 2.4.2 with fts-flatcurve.
> >
> > However, I am seeing a giant jump in the size of the indexes.
> >
> > For an email account that takes 12GB of storage, I get the following
> index
> > sizes:
> >
> >    - lucene: 270 MB
> >    - flatcurve: 2400 MB
> >
> >
> > That is almost a 10x increase in the index size (with flatcurve the
> indexes
> > represent 20% of the size of the mailbox).
>
> Hi!
>
> You have substring search enabled, that will incur a larger size as those
> substrings need to be indexed somewhere.
>
> Aki
>
>

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