Cache Swift Heads
John was pointing on IRC that the headers on a account HEAD are not served from the cache while we can do some clever things there.
Although stored in the cache :
we are not using it.
The conditions are :
As long it is a simple HEAD without a query string and there's info about it in the memcache just return that.
If it has a X-Newest headers it has to go to the storage nodes and not served by the cache (i.e: see code from here http://
Blueprint information
- Status:
- Started
- Approver:
- Chmouel Boudjnah
- Priority:
- Undefined
- Drafter:
- None
- Direction:
- Needs approval
- Assignee:
- Fabien Boucher
- Definition:
- Drafting
- Series goal:
- None
- Implementation:
-
Blocked
- Milestone target:
- None
- Started by
- Fabien Boucher
- Completed by
Related branches
Related bugs
Sprints
Whiteboard
This is a report for the difficulties I encountered when trying to implement this blueprint.
I've tried to implement something to be able to build a response from the proxy cache account entry to a HEAD request but I was faced to a problem due to Container-count and Bytes-used meta. Those meta are updates by container server by performing a direct PUT on the account server. There is no easy way to invalidate the proxy memcache entry for the related account.
Furthermore how to handle the X-newest header if we use the cached meta to build a response as
we would have three layers (cached, one replica, all replica) to grab the data.
Gerrit topic: https:/
This patchset is not complete, I've haven't publish my latest code:
Addressed by: https:/
AccountCont
