HR Issues (But Up time is great)
Brandon Wirtz
So they are all in one place, here are the things I know to be an Issue with HR:
1. Caching doesn’t work, and because of the way headers are forced to be set all requests expire immediately so the user won’t cache either.
(Headers from a request)
HTTP/1.1 405 Method Not Allowed
Content-Type: text/html; charset=utf-8
Cache-Control: no-cache, must-revalidate
Expires: Fri, 01 Jan 1990 00:00:00 GMT
Set-Cookie: S=apphosting=5hoCHm4x9c3ZrrxQEN5Q4A; path=/
Date: Sat, 19 Mar 2011 19:37:21 GMT
Pragma: no-cache
Server: Google Frontend
Content-Length: 0
This happens even if you programmatically set output to have some other expiration, pragma, and/or cache-control.
2. Charts in the dash board only go back 24 hours.
Vs. up to 30 days for Master Slave.
3. Data Store Viewer always errors if you try to edit entities.
This works most of the time when I use MS… (not always but mostly)
4. This isn’t so much an “issue” as an observation. I get a higher error rate on HR at the same time I get higher rates on MS. Sometimes I get errors on MS and won’t get them on HR, but it seems anytime my error rate goes up on HR it is up on MS as well.
Most of these errors are “memcache.add failed” [ ok in my app that is the only error I ever get, but that’s cause my code is perfect it’s the platform that has issues :-) ]
nickmilon
Could it be by design ?
Have others observed this ?
happy coding:-)
Nick
On Mar 19, 10:32 pm, "Brandon Wirtz" <drak...@digerat.com> wrote:
> So they are all in one place, here are the things I know to be an Issue with
> HR:
>
> 1. Caching doesn't work, and because of the way headers are forced to
> be set all requests expire immediately so the user won't cache either.
>
> (Headers from a request)
>
> HTTP/1.1 405 Method Not Allowed
> Content-Type: text/html; charset=utf-8
> Cache-Control: no-cache, must-revalidate
> Expires: Fri, 01 Jan 1990 00:00:00 GMT
> Set-Cookie: S=apphosting=5hoCHm4x9c3ZrrxQEN5Q4A; path=/
> Date: Sat, 19 Mar 2011 19:37:21 GMT
> Pragma: no-cache
> Server: Google Frontend
> Content-Length: 0
>
> This happens even if you programmatically set output to have some other
> expiration, pragma, and/or cache-control.
>
> 2. Charts in the dash board only go back 24 hours.
>
>
>
> 4. This isn't so much an "issue" as an observation. I get a higher
> error rate on HR at the same time I get higher rates on MS. Sometimes I get
> errors on MS and won't get them on HR, but it seems anytime my error rate
> goes up on HR it is up on MS as well.
>
> Most of these errors are "memcache.add failed" [ ok in my app that is the
> only error I ever get, but that's cause my code is perfect it's the platform
> that has issues :-) ]
>
> 43KViewDownload
>
> image002.png
> 32KViewDownload
>
> image003.png
> 51KViewDownload
Simon Knott
My experience for a Java app is:
1) Caching seems to work fine for my app - how are you being forced to set headers? Do you have sessions enabled?
2) My dashboard only goes back 24hrs as well.
3) I can edit entities fine in the datastore - does this error happen when you edit properties of a specific type, or for any properties?
4) I experience a bit more latency for MemCache on the HR version of my app, than the MS version. I don't have anywhere near the amount of traffic you do however, so I haven't noticed any actual errors in this area.
Ikai Lan (Google)
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Brandon Wirtz
Python.
Can I check your headers? (like via a URL) because even my static files I can’t get the cache-control / expire to be honored.
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Brandon Wirtz
Ikai,
What about the Cache Control/Pragma/Expires headers. Any ideas as to if those always being set to do not cache is by design?
Oh, and it isn’t exactly a higher error rate, it is just “an error rate” there are times you can’t write to mem-cache it’s not a big deal, just something that would be cool if it didn’t happen (or as much).
-Brandon
Ikai Lan (Google)
Brandon Wirtz
Ikai,
It’s not for edge Caching, it is so that when I serve the CSS and JPG files for a page that subsequent pages that use those same assets will not require re-downloading the images and CSS.
It’s also to help Curb the Google Bot, which has its own “fun” issues one of which being that you can’t specify a crawl rate on an AppEngine Hosted site in webmaster tools, and if the cache control is always set to expire, Google bot will crawl 10k pages, finish, and say “Hey All these expired let’s crawl them again and see what changed. On several of my sites Google Bot is 80% of my traffic. Which is fine, but he never clicks on any ads :-) so he is really hard to monetize.
Simon Knott
- Accept:*/*
- Accept-Charset:ISO-8859-1,utf-8;q=0.7,*;q=0.3
- Accept-Encoding:gzip,deflate,sdch
- Accept-Language:en-GB,en-US;q=0.8,en;q=0.6
- Cache-Control:max-age=0
- Connection:keep-alive
- Cookie:S=apphosting=lJdUb2lQFokus??f0BDw; ACSID=AJKiYcHLHu0ykssZOsp0RuHamFvmI1omlz-???0XKQKzFrO_K_gnleJxN36w249QujsmCt-nc5oberCcX67nwhPjbuWjO7CNilEgT8iSoGzBDXFqERzEJQIbCcl8zuoNodt9J7v7AMGsr8UAnGiTNyS_64fp9XHquPUjcOWxB-NYXj1sUBEHSc0ydm84a8noDh67exBjzjAz4YqhceiQ1LGOiy3I9avRQ1eljUkjTkvRZb32gwrFpTIGNDS5yp0q_2909_u0Q1YsFLBADy7HS6W38iAv9qTEuqyO23Z5jB5KfXU2Cuot_PTi_uQH2kIjjI6-r2g3cvRv4GGhRTz9NtvGfZbtWOayK1jEKKRhAOeUZPjEE38N8VIke2n-UsguOBnViIOOSM4ELgL_RAnx6ztrhU_5bvaoevRa2Xab7urhurhWtVZCQzv3UxbJro1Y????hGZoTdApvGOpUHQH51EQZ6xiyGGz4kgYlToUzyZLBHLYFvPN8CyMTFrdTGzlaUJAaGMOF2_W5W3EE7s0GtiOf6_1XqNSoNPzod9BzCI_Mhk
- Host:xxx
- If-None-Match:"-n5uDA"
- Referer:xxx
- User-Agent:Mozilla/5.0 (Windows NT 6.1) AppleWebKit/534.24 (KHTML, like Gecko) Chrome/11.0.696.14 Safari/534.24
Stephen
>
> 1. Caching doesn’t work, and because of the way headers are
> forced to be set all requests expire immediately so the user won’t cache either.
>
> (Headers from a request)
>
> HTTP/1.1 405 Method Not Allowed
> Content-Type: text/html; charset=utf-8
> Cache-Control: no-cache, must-revalidate
> Expires: Fri, 01 Jan 1990 00:00:00 GMT
> Set-Cookie: S=apphosting=5hoCHm4x9c3ZrrxQEN5Q4A; path=/
> Date: Sat, 19 Mar 2011 19:37:21 GMT
> Pragma: no-cache
> Server: Google Frontend
> Content-Length: 0
These look like headers from a response, not a request, and the
response code is 405: Method Not Allowed. ie. the request was
something other than a GET, POST, PUT or DELETE, in which case you
might expect the error response to force a no-cache header.
Are you sure your test is accurate?
Brandon Wirtz
Cause out of the same tool, now I get
HTTP/1.1 200 OK
Via: HTTP/1.1 GWA (remote cache hit)
Accept-Ranges: bytes
Last-Modified: Wed, 02 Mar 2011 01:25:48 GMT
Etag: "159827d-169b0-49d75caeb5f00"
Content-Type: image/png
Age: 6985
Cache-Control: public; max-age=300
Date: Tue, 22 Mar 2011 02:29:27 GMT
Server: Google Frontend
Content-Length: 92592
Which even says that Google gave me a cache hit. Which is interesting cause
the Dashboard on the app doesn't claim it has any of those. (even though My
MS version of the app does)
So just ignore me, it seems to work well enough, I'm just partially insane.
:-)
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