Re: BUG #19639: EXPLAIN (FORMAT JSON) emits a 309-digit cost value, and the node still reports "Disabled": false

On Tue, 25 Aug 2026 at 00:16, PG Bug reporting form
<noreply(at)postgresql(dot)org> wrote:
> On 19beta3, EXPLAIN (FORMAT JSON) can emit a cost of DBL_MAX, rendered as a
> 309-digit number. serde_json rejects it with "number out of range", and I
> would
> expect most plan-analysis tooling to have the same problem, since there is
> no
> way for a client to consume it other than parsing the number as text.

Does serde_json parse it if you add a .0 to the end of the number?

Maybe they should consider switching to doubles if the number
overflows the integer type they're using.

RFC8259 does say:

"This specification allows implementations to set limits on the range
and precision of numbers accepted. Since software that implements
IEEE 754 binary64 (double precision) numbers [IEEE754] is generally
available and widely used, good interoperability can be achieved by
implementations that expect no more precision or range than these
provide, in the sense that implementations will approximate JSON
numbers within the expected precision. A JSON number such as 1E400
or 3.141592653589793238462643383279 may indicate potential
interoperability problems, since it suggests that the software that
created it expects receiving software to have greater capabilities
for numeric magnitude and precision than is widely available."

So it does seem a bit poor if their parser failed on DBL_MAX.

David