Ashish Goel <postgres_help(at)yahoo(dot)com> writes:
> We have a following table xyz( id int , fname varchar(50), img image)
> where image is a data type we have created similar to lo.
> ...
> Can somebody suggest us what might be the cause of error and what can we do to resolve it ?
Incorrect code in your custom datatype, almost certainly. Check
computations of memory size allocations, for example. Test it in
a backend compiled with --enable-cassert.
regards, tom lane