[RFC PATCH] REST: Add new setting for maximum API page size

[Andrew Donnellan]

On 26/07/18 23:24, Daniel Axtens wrote:
> Andrew Donnellan <andrew.donnellan at au1.ibm.com> writes:
> 
>> On 24/07/18 15:10, Andrew Donnellan wrote:
>>> In 41790caf59ad ("REST: Limit max page size") we limited the maximum page
>>> size to the default page size in the settings.
>>>
>>> This turns out to be rather restrictive, as we usually want to keep the
>>> default page size low, but an administrator may want to allow API clients
>>> to fetch more than that per request.
>>>
>>> Add a new setting, MAX_REST_RESULTS_PER_PAGE, to set the maximum page size.
>>>
>>> Closes: #202 ("Separate max API page size and default API page size into different settings")
>>> Suggested-by: Stewart Smith <stewart at linux.ibm.com>
>>> Suggested-by: Joel Stanley <joel at jms.id.au>
>>> Signed-off-by: Andrew Donnellan <andrew.donnellan at au1.ibm.com>
>>
>> FWIW we now have this applied on patchwork.ozlabs.org and it appears to
>> be working. Would like some more input as to what an appropriate default
>> limit is.
> 
> My completely fact-free feeling/opinion is that if it takes more than
> ~1sec to run on Ozlabs, it's probably too high. Apart from that, I'm not
> fussed.

OzLabs.org is not a fast machine. 1 second round trip time == 100 per 
page. 500 per page == ~2.3 seconds round trip.

A single 500 item load is still under half the time of doing 5 * 100 
item loads...

-- 
Andrew Donnellan              OzLabs, ADL Canberra
andrew.donnellan at au1.ibm.com  IBM Australia Limited