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