pcp
[Top] [All Lists]

Re: [pcp] pcp update: json pmda

To: "Frank Ch. Eigler" <fche@xxxxxxxxxx>, pcp developers <pcp@xxxxxxxxxxx>
Subject: Re: [pcp] pcp update: json pmda
From: Mark Goodwin <goodwinos@xxxxxxxxx>
Date: Tue, 09 Jun 2015 11:30:10 +1000
Delivered-to: pcp@xxxxxxxxxxx
In-reply-to: <20150609004114.GA9357@xxxxxxxxxx>
References: <20150609004114.GA9357@xxxxxxxxxx>
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0
On 06/09/2015 10:41 AM, Frank Ch. Eigler wrote:
Hi -

Please see git://sourceware.org/git/pcp.git branch fche/json for this ditty:
                           ----------^^^^^  pcpfans.git


Author: Frank Ch. Eigler <fche@xxxxxxxxxx>
Date:   Mon Jun 8 20:34:39 2015 -0400

     json pmda: tolerate json array instances that are missing -> PM_ERR_INST

     Because of the caching of json array elements in the indom cache
     (/var/lib/pcp/config/pmda/137.*), it is easy to get the pmda machinery
     to recall indom entries that do not currently exist.  Prior to this
     patch, sending those indoms to the pmda fetch-handler resulted in
     needless error messages (and related slowdowns).  We now return the
     correct error (PM_ERR_INST) and don't log anything.

Hi Frank,

the patch itself looks ok to me, but as I read it, this is not just an err
handling issue - if the cache has stale entries then that suggests the root
cause of this issue is in the refresh functionality - shouldn't it invalidate
all entries and then re-activate only those still current (plus any new
instances)?

Also, some qa to demonstrate the issue and the fix would be appropriate,
especially at this stage of the release.

Thanks
-- Mark

<Prev in Thread] Current Thread [Next in Thread>