Preliminary load testing

[melissachang]

Requested by @seanhorgan.

I simulated 20-100 simultaneous users of NHS Data Explorer, to simulate a workshop. Data Explorer was slower, but still usable.

The slowest part of Data Explorer is doing a search on large datasets like NHS. Searching for pre takes ~6 sec; men takes ~5s.

20 simultaneous searches

• DE loaded in all tabs
• Search times: 4 3 8 7 11 10 14 12 16 15 19 19 20 22 23 25 25 27 27 29

100 simultaneous searches

• DE didn't load for 35 out of 100 tabs. (To me this is fine; user can just reload.)
• For tabs where DE did load, search times: 4 4 8 6 9 13 8 15 10 13 18 16 20 18 23 19 26 21 30 18 32 21 33 26 34 27 36 32 42 16 41 37 48 40 46 37 49 47 57 46 61 38 59 36 66 46 64 45 71 47 61 48 72 31 73 55 76 36 61 59 71 35 75 33 68 41

Implementation notes

Unfortunately this requires manually scrolling through Chrome tabs.

• When headless if off, only the focussed tab browser test code will execute.
• This issue doesn't happen when headless is on. But when headless is on, I'm not able to manually login to channing account. I tried writing code to automate this, but got stuck because Google starting asking for captcha.
• Multiple browser contexts don't have this problem -- With headless off, test code in all contexts runs simultaneously. However, I'd have to manually log into each context which is a pain.

[melissachang]

Simultaneous searching would only happen in the context of a workshop, so I'm not too concerned about the results. For workshop, I just want to make sure the application doesn't totally fall over.

For NHS, we get about 1-2 users a week. It would be a long time before we get many simultaneous searches organically.