Polishing queries

[AnttiRumpunen]

In 4.1.0 app executed timeseries, autocomplete, warnings -queries which can be optimised in the following way. Idea is to get more hits to cache and remove obsolete queries.

Startup (weather page opens)

• warnings is fetched once with way too many decimals. Use 4 digits instead of 15.
• Location defining uses way too many decimals. Latlon should use 4 digits instead of 15.

Locate self

• same as above. Latlon should use 4 digits instead of 15.

Opening saved/previous location

• fetches observations 4 times, is 2 times enough? (my test notes a bit inaccurate... 2 x with geoid + hourly/daily obs = 4 queries)
• Warnings are fetched twice. Is one time enough?

Searching location

• Autocomplete query is fired from each character. Can there be one second or similar timeout before firing the query? Needs a bit of testing which feels best.

Selected searched location

• warnings is fetched twice. Would once be possible?

Opening map page (time series -layer is selected)

• starttime is too accurate. Can be rounded to next full hour.

Opening Weather page

• warnings is fetched with 15 digit accuracy, change to 4 digits.

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Notes from heiskanen:

• Observation timeseries -query has cache-control: no-cache. Maybe set to public + max-age=X, where X depends on queried parameter.
• WMS observation -queries have Accept-Encoding: gzip. Is it needed when fetching png/webp images? Not really...
• WMS forecast -queries have ETAG. Timeseries doesn't, why?

[geosaaga]

Implemented most of suggested optimizations in PR https://github.com/fmidev/weather-app/pull/621

Warning data updates and app startup time could be further optimized by adding version number to DynamicConfig #620

Didn't implement or change these:

• Removed Cache-Control: no-cache header, but didn't implement Maybe set to public + max-age=X, where X depends on queried parameter. Server should control cache times, not the app.
• WMS observation -queries have Accept-Encoding: gzip, these headers are sent by native map libraries (Google Maps, Apple Maps) and can't change those.
• WMS forecast -queries have ETAG. Timeseries doesn't, why? Both should have ETAG according to my tests if the same query has been done before. But of course the first query is without ETAG.