Bad Signature - Both Roundcube and Squirrelmail webmail cannot search for anything + cannot open many emails because there are more than 200, 000 emails in my Inbox

Sam Kuper sampablokuper at
Wed Apr 20 06:20:38 UTC 2022

On Tue, Apr 19, 2022 at 07:26:10PM -0600, Shawn Heisey wrote:
> I would bet that if you accessed a gmail folder with 5 million
> messages in it using IMAP, you would have similar problems with it to
> those that have been described here in this thread.  IMAP is a
> beautiful protocol, but I don't think it was designed for handling
> that many messages.

This.  Sadly, Mark Crispin (author of IMAP and IMAP2) is no longer with
us to confirm.

Even at just ~100B for each message's headers, your IMAP2 client would
likely need at least ~500MB free RAM to load 5 million mails.

By the time Mark stopped working on UW IMAP (the reference IMAP
implementation, aka Panda IMAP), c.2010, even top-of-the-range
smartphones typically had only ~512MB RAM total, and top-of-the-range
ThinkPads had max ~4GiB (which was the upper limit of what 32-bit
operating systems, still popular then, could handle).

When IMAP2 was invented, c.1988-1990, RAM like that was basically
supercomputer territory.

Had Mark intended or expected IMAP2 users to have had supercomputers at
their disposal, and to be searching such large volumes of mail over the
protocol, I suspect he would have designed the protocol differently: for
raw efficiency over human readability.

My advice for anyone who wants to be able to keep and search very large
monolithic mailstores would be: synchronise (e.g. via or fetchmail or getmail or rsync or Unison
or whatever) those mailstores from the server onto your local
filesystem; use maildir on your local filesystem; and use either Mutt's
"limiting" functions, or notmuch's index/search functions, for

Good luck in your quest!


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