Re: IN question

[Josh Berkus <josh(at)agliodbs(dot)com>]

Jeff Davis wrote:
> On Wed, 2008-12-10 at 16:11 -0800, Neil Conway wrote:
> > On Wed, Dec 10, 2008 at 3:39 PM, Jeff Davis <pgsql(at)j-davis(dot)com> wrote:
> > > And if it's additional memory, it should probably be a different GUC.
> > Measuring the limit in bytes makes no sense, anyway.
>
> Sure it does. If you're concerned about the application generating
> infinite SQL strings and sending them to the server, a byte limit on the
> SQL string would solve it.
>
> After all, as Josh pointed out, there _is_ a limit measured in bytes:
> available memory (and some operating systems don't handle that very
> well).

Yes.  For example, if the length of your query exceeds any of various 
memory limits on Linux, the connection crashes with a very unfriendly 
error message.  If it was our limit, the error message could at least be 
friendly: "Query string too long.  Please edit the query or increase 
work_mem."

And infinite SQL isn't hypothetical; just 4 weeks ago I fixed a problem 
for a client which turned out to be their home-baked ORM building IN() 
clauses up to 150,000 values long.

--Josh