7.7.0 general performance problems, blocking IE11

[LeeDr]

Kibana version: 7.7.0-snapshot

Elasticsearch version: 7.7.0-snapshot

Server OS version: Windows 10

Browser version: IE11

Browser OS version: Windows 10

Original install method (e.g. download page, yum, from source, etc.): default dist zips

Describe the bug: Changes from 7.6 to 7.7.0 (new platform build?) have caused generally worse performance for Kibana loading and switching between apps in any browser. And it's significant enough to cause IE11 to either not load some apps (such as Canvas) or to frequently quit and reload Kibana.

Steps to reproduce:

1. run Kibana 7.7.0 in IE11, compare to 7.6.2

Expected behavior: Even though we add features to Kibana we should also try to improve performance.

Screenshots (if relevant):

Errors in browser console (if relevant):

Provide logs and/or server output (if relevant):

Any additional context:

This is very likely to impact Cloud deployments, and Reporting. But not confirmed yet.

[elasticmachine]

Pinging @elastic/kibana-operations (Team:Operations)

[LeeDr]

A couple of statistics about the change from the latest 7.6.2 to this 7.7.0 default distribution Windows zip files;

Version	zip file size	File count
7.6.2	291MB	99,003
7.7.0	367MB	163,977

A lot of the bundle names don't match up between releases. But here's some data on the ones that do;

Bundle	7.6.2 size	7.7.0 size	% change
canvas.bundle.js	12152030	12265199	0.9%
commons.bundle.js	7629678	8379439	9.8%
apm.bundle.js	730165	2379977	226.0%
kibana.bundle.js	5318708	2168995	-59.2%
monitoring.bundle.js	951781	1023270	7.5%
uptime.bundle.js	372167	512140	37.6%
siem.bundle.js	199334	423438	112.4%
timelion.bundle.js	96378	97078	0.7%
maps.bundle.js	35120	37552	6.9%
status_page.bundle.js	32406	33800	4.3%
dashboardViewer.bundle.js	10300	10149	-1.5%
lens.bundle.js	8888	8812	-0.9%
core.bundle.js	8389	8311	-0.9%
dark_theme.bundle.js	2166	2058	-5.0%
light_theme.bundle.js	2167	2058	-5.0%

[spalger]

Expected behavior: Even though we add features to Kibana we should also try to improve performance.

This was a trade off that we decided to take because we really need to get rid of the optimizer in production, and our design to accomplish this included some code duplication that we were expecting. We expected that this might cause initial page load times to be slower, but it also meant that the assets would be more stable, Kibana would be more reliable, run with less memory required server side, and most importantly, be able to remove the loading indicator between apps. In order to get there we needed to increase the side of each bundle.

What we didn't know, or expect, was that the size of the bundles would grow so large that IE would stop working.

This has surprised us and lead to us pulling some emergency levers to reduce the overall size of the code (#62364) and a few that will reduce the size of the code initially loaded on a page (#62344, #62363, #62403, #62408, #62434, #62487, #62493).

I'm also working on reporting improvements so that in the 7.8 timeframe we will be able to analyze how big bundles are, and how changes we are making impacts the size of those bundles. Shortly after that's done we want to tie that into the reporting done on PRs so that PR authors will be confronted with the impact their PR has on the bundle sizes early and we won't be surprised by this down the road.

[mshustov]

What we didn't know, or expect, was that the size of the bundles would grow so large that IE would stop working.

Right now we focus on an assumption that memory usage is the bottleneck for IE.
In theory, we might have another problem that could affect IE is a page load time. In v7.7 Kibana performs ~120 requests to load client-side assets, which might cause timeout error. If all our current improvements don't help much, we will switch to #55241 to improve load time.

[pgayvallet]

As long as IE11 is a targeted browser, shouldn't we have a few windows CI nodes with IE11 to at least run some smoke tests on that environment? It seems like we currently have no way to have any idea of the performances / issues of running kibana on that specific browser, which cause the actual issues to be detected extremely late in our testing process, if not by end user themselves.

[tylersmalley]

Action items from this mornings sync:

• Continue to add async loaders to largest contributors (@restrry )
• Temporarily add data plugin to shared-deps [kbn/optimizer] link to kibanaReact/kibanaUtils plugins #62720 (@spalger)
• Investigate major increase in legacy bundle size for APM/SIEM (@mistic)
• Enable tree shaking for new platform plugins Enables tree shaking in production for plugins  #62390 (@tylersmalley)
• Generate full report for difference between 7.7.0 BC4 and 7.6.2 (@tylersmalley)

[tylersmalley]

I am tracking the changes of Javascript assets which are loaded when accessing the home page:

https://docs.google.com/spreadsheets/d/16mB-yZAHoMBYgExXC5gdSjNVROrNCs0z6Dt7MEd8ilA/edit#gid=0