Re: Patch: Allow substring/replace() to get/set bit values

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Leonardo F <m_lists@yahoo.it>
Cc: Robert Haas <robertmhaas@gmail.com>, pgsql-hackers@postgresql.org
Date: 2010-01-07T16:58:14Z
Lists: pgsql-hackers
Leonardo F <m_lists@yahoo.it> writes:
> I've even got 
> "ERROR:  invalid memory alloc request size 4244635647" 
> with:
> SELECT substring(B'1111000000000001' from 5 for -2);

Hm, yeah, somebody was sloppy about exposing the three-argument
form of varbit substring and using -1 to represent the two-argument
form.

What we can do in the back branches is make the code treat any
negative value as meaning two-arg form.  To throw an error we'd
need to refactor the pg_proc representation ...

			regards, tom lane