Custom dimensions: what are total bytes into the payload ?

[Onofrio Sasso]

Hi,

I'm using Google Analytics Measurement Protocol in POST.

In my experiments the max total bytes for the "twenty" custom dimensions sent successfully into Analytics is 1397,

while the max total bytes for the "single" custom dimension sent successfully into Analytics is 1097.

The documentation says that the max total bytes for payload is 8192 bytes and that the max total bytes for single custom dimension is 150 bytes.

Why the total bytes dedicated to custom dimensions is so small? Only 1397 bytes of 8192 ?

Some help, please?

Thank you.

Regards.

Onofrio Sasso