We're not shipping the sourcemap files, and while the assets minifier
strips out the mappings they're getting hit in debug=assets which is
bot useless and problematic when running odoo-bin without a proxy for
static folders: if sourcemaps are enabled (which is apparently the
default in all browsers if devtools are opened at this point) the
browser tries to fetch the sourcemap, which does through the
SharedDataMiddleware which doesn't find them and passes the query on
to the regular Application which goes through the entire dispatch &
NotFound process.
If website is installed, that process ends up rendering website.404,
which can be pretty costly until everything is properly cached:
# initial request
"GET /web/static/lib/bootstrap/js/index.js.map HTTP/1.1" 404 - 319 0.198 0.954
# a few requests later
"GET /web/static/lib/bootstrap/js/index.js.map HTTP/1.1" 404 - 27 0.022 0.060
And the way sourcemaps are fetched (might be headers, might be the
stampede as browsers will try to fetch a dozen sourcemaps as fast as
possible) seems to make this problem much, much worse: instead of 300+
the requests take 800+ queries each, multiple seconds, and requests
get worse as time goes on (didn't investigate the exact reason for
that) *and* they apparently don't ever get cached (at least they don't
after half a dozen reloads of the client).
Xavier Morel
8e17223c26