From: Tom Lane <tgl@sss.pgh.pa.us>
To: Pavel Stehule <pavel.stehule@gmail.com>
cc: Richard Wesley <richard@duckdblabs.com>,
        PostgreSQL mailing lists <pgsql-bugs@lists.postgresql.org>
Subject: Re: Query generates infinite loop
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Comments: In-reply-to Pavel Stehule <pavel.stehule@gmail.com>
	message dated "Wed, 20 Apr 2022 18:53:33 +0200"
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Date: Wed, 20 Apr 2022 13:03:45 -0400
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Pavel Stehule <pavel.stehule@gmail.com> writes:
> st 20. 4. 2022 v 18:42 odes=C3=ADlatel Richard Wesley <richard@duckdblab=
s.com>
> napsal:
>> select COUNT(*) FROM generate_series('-infinity'::TIMESTAMP, 'epoch'::T=
IMESTAMP, INTERVAL '1 DAY');
>>
>> This seems like a DoS great attack, so we are disallowing infinities as
>> bounds for both table and scalar series generation. As an upper bound, =
it
>> eventually gives an error, so it seems  there is not much utility anywa=
y.

> There are more ways to achieve the same effect. The protection is safe
> setting of temp_file_limit

Well, there are any number of ways to DOS a database you can issue
arbitrary queries to.  For instance, cross joining a number of very
large tables.  So I'm not excited about that aspect of it.  Still,
it's true that infinities as generate_series endpoints are going
to work pretty oddly, so I agree with the idea of forbidding 'em.

Numeric has infinity as of late, so the numeric variant would
need to do this too.

I think we can allow infinity as the step, though.

			regards, tom lane