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

[Stewart Smith]

Andrew Donnellan <andrew.donnellan at au1.ibm.com> writes:
> 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...

I bet MySQL would execute the query quicker :)

Anyway, that sounds really quite slow and we should look at why on earth
it's that slow - is there some kind of horrific hidden join or poor
indexing or query plan or something?

-- 
Stewart Smith
OPAL Architect, IBM.