James Cloos wrote:
> This query in psql does give me the header of a message sent to this
> group:
>
> ,----
> | select physmessage_id from dbmail_messageblks where is_header = 1
> | and convert_from(messageblk,'SQL_ASCII') ~ 'dbmail-dev' limit 1;
> `----
>
> It is, however, as one might expect quite slow.
>
> If one blindly uses 'SQL_ASCII', octets other than those from in /[\n\t -~]/
> aka /\n\t\x20-\x7E/ seem to be output as C-style backslash escapes.
> That may or may not be useful for imap search.
>
> There is also the question of whether imap search is supposed to search
> the over-the-wire format of the mail or the as-viewed-in-an-MUA format.
> Ie, how imap search and mime are supposed to interact.
The RFC is very clear on that one:
Server implementations MAY exclude [MIME-IMB] body parts with
terminal content media types other than TEXT and MESSAGE from
consideration in SEARCH matching.
So we don't need to match base64 encoded data, etc.
Also consider this:
In all search keys that use strings, a message matches the key if
the string is a substring of the field. The matching is
case-insensitive.
We try to avoid regexp matching for (possibly) historical performance
reasons, hence the use of ILIKE.
> This query would get all of the mail which have 'dmail-dev' in their
> bodies, ordered by physmessage_id. But it is wildly disk intensive,
> as psql has to read through every messageblk in dbmail_messageblks.
No way around that without full text indexing.
--
________________________________________________________________
Paul Stevens paul at nfg.nl
NET FACILITIES GROUP GPG/PGP: 1024D/11F8CD31
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