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https://issues.apache.org/jira/browse/TS-2314?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14153432#comment-14153432
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Sudheer Vinukonda commented on TS-2314:
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Agree - the reason Im just checking the end-byte to decide to tunnel the
request is to avoid more complexity by adding more settings - i.e, I wanted to
avoid this - "arguably, to optimize further you would want one or more
thresholds, since if you are one byte away from the start of the range it is
almost the same as if you are one byte past the start...so you would want to
say "if the first byte of the highest range is <
read_while_write_range_close_limit away, just wait..."
:=) there's already a bunch of related settings that affect RWW, and we are
currently considering making them overridable. I do see the value in what you
are suggesting. If you strongly feel about it, I can work on it sometime in the
near future.
> New config to allow unsatifiable Range: request to go straight to Origin
> ------------------------------------------------------------------------
>
> Key: TS-2314
> URL: https://issues.apache.org/jira/browse/TS-2314
> Project: Traffic Server
> Issue Type: Bug
> Components: Core
> Reporter: jaekyung oh
> Assignee: Sudheer Vinukonda
> Labels: range
> Attachments: TS-2314.diff
>
>
> Basically read_while_writer works fine when ATS handles normal file.
> In progressive download and playback of mp4 in which moov atom is placed at
> the end of the file, ATS makes and returns wrong response for range request
> from unfulfilled cache when read_while_writer is 1.
> In origin, apache has h264 streaming module. Everything is ok whether the
> moov atom is placed at the beginning of the file or not in origin except a
> range request happens with read_while_writer.
> Mostly our customer’s contents placed moov atom at the end of the file and in
> the case movie player stops playing when it seek somewhere in the movie.
> to check if read_while_writer works fine,
> 1. prepare a mp4 file whose moov atom is placed at the end of the file.
> 2. curl --range xxxx-xxxx http://www.test.com/mp4/test.mp4 1>
> no_cache_from_origin
> 3. wget http://www.test.com/mp4/test.mp4
> 4. right after wget, execute “curl --range xxxx-xxxx
> http://www.test.com/mp4/test.mp4 1> from_read_while_writer” on other terminal
> (the point is sending range request while ATS is still downloading)
> 5. after wget gets done, curl --range xxxx-xxxx
> http://www.test.com/mp4/test.mp4 1> from_cache
> 6. you can check compare those files by bindiff.
> The response from origin(no_cache_from_origin) for the range request is
> exactly same to from_cache resulted from #5's range request. but
> from_read_while_writer from #4 is totally different from others.
> i think a range request should be forwarded to origin server if it can’t find
> the content with the offset in cache even if the read_while_writer is on,
> instead ATS makes(from where?) and sends wrong response. (In squid.log it
> indicates TCP_HIT)
> That’s why a movie player stops when it seeks right after the movie starts.
> Well. we turned off read_while_writer and movie play is ok but the problems
> is read_while_writer is global options. we can’t set it differently for each
> remap entry by conf_remap.
> So the downloading of Big file(not mp4 file) gives overhead to origin server
> because read_while_writer is off.
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