Bug 868087 - Multiple memcache key/value pairs are used to store metadata for account and containers
Summary: Multiple memcache key/value pairs are used to store metadata for account and ...
Keywords:
Status: CLOSED CURRENTRELEASE
Alias: None
Product: GlusterFS
Classification: Community
Component: object-storage
Version: pre-release
Hardware: x86_64
OS: Linux
unspecified
medium
Target Milestone: ---
Assignee: Peter Portante
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2012-10-19 04:13 UTC by Peter Portante
Modified: 2014-07-11 16:16 UTC (History)
3 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2014-07-11 16:16:48 UTC
Regression: ---
Mount Type: ---
Documentation: ---
CRM:
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Description Peter Portante 2012-10-19 04:13:20 UTC
Description of problem:

  Currently, three memcache key/value pairs are used to cache the metadata for
  accounts and containers.

  This is both a potential data integrity problem and a performance issue.

  The data integrity problem can arise from two actors setting the various
  keys to different sets of computed values, or a reader fetching a partial
  set before a writer updates one of the keys.

  It is a performance problem in that we have triple the network traffic
  hitting the memcache servers.

Version-Release number of selected component (if applicable):

  RHS 2.0

How reproducible:

  Readily

Steps to Reproduce:
1. Hook up wireshark
2. Observe traffic two and from a memcache server
3. Notice for a given Swift API GET on a container, three memcache GET
   operations are performed
  
Actual results:

  3 memcache GET operations performed per Swift API GET on a container/account

Expected results:

  1 memcache GET operation performed per Swift API GET

Additional info:

Comment 1 Peter Portante 2012-10-19 04:14:12 UTC
I'll take this as I am currently working on performance improvements in the module containing the code for this behavior.

Comment 2 Vijay Bellur 2012-11-03 11:37:27 UTC
CHANGE: http://review.gluster.org/4139 (object-storeage: refactor to use one memcache key) merged in master by Vijay Bellur (vbellur)


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