Re: How much data does server side "loread" return?

On Thu, 2021-06-24 at 15:24 +0200, Thorsten Schöning wrote:
> I need to read some large object and am wondering how much data
> "loread" returns in case it successfully reads at all AND the object
> contains at least as much data as requested.
>
> In that case, does "loread" always return the requested amount of data
> or does one need to always loop when calling that function?

That SQL function just calls the C function lo_read, see
https://www.postgresql.org/docs/current/lo-interfaces.html#LO-READ

The documentation there says:

"The number of bytes actually read is returned; this will be less than 'len'
if the end of the large object is reached first. In the event of an error,
the return value is -1."

So it will always read as many bytes as possible.

Yours,
Laurenz Albe
--
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