----- Original Message ----- > From: "Itamar Heim" <ih...@redhat.com> > To: "Barak Azulay" <bazu...@redhat.com> > Cc: "engine-devel" <engine-devel@ovirt.org> > Sent: Wednesday, June 12, 2013 10:09:09 AM > Subject: Re: [Engine-devel] Updates in VdsUpdateRuntimeInfo > > On 06/12/2013 09:41 AM, Barak Azulay wrote: > > > > > > ----- Original Message ----- > >> From: "Itamar Heim" <ih...@redhat.com> > >> To: "Liran Zelkha" <lzel...@redhat.com> > >> Cc: "engine-devel" <engine-devel@ovirt.org> > >> Sent: Tuesday, June 11, 2013 4:00:21 PM > >> Subject: Re: [Engine-devel] Updates in VdsUpdateRuntimeInfo > >> > >> On 06/11/2013 03:26 PM, Liran Zelkha wrote: > >>> Hi all, > >>> > >>> I'm checking performance for VdsUpdateRunTimeInfo. > >>> Naturally, much of the performance surrounds database activity > >>> (getVmsRunningOnVds queries, updateDeviceRuntimeInfo, updateVmDynamic) > >>> > >>> Few questions: > >>> 1. I have implemented batch updates for procedure > >>> UpdateVmDeviceRuntimeInfo > >>> for improved performance. > >>> 2. Seems like the only parameters UpdateVmDeviceRuntimeInfo is getting > >>> are > >>> vm_id,vm_device_id,address and alias. Are those rapidly changing, or will > >>> it be beneficial to implement caching on those updates (to ensure > >>> not-required updates do not travel to the database). > >> > >> slowly changing, but how will you cover all flows changing these devices > >> to invalidate the cache (iiuc, this table is modified by engine when > >> adding devices to a VM as well?) > > > > > > I don't think that in the device run time info we need to invalidate once > > we add a device. > > This is a specific case where we actually get the information from the VDSM > > (addresses are received from libvirt) > > The commands IIRC are first send to VDSM and than update the runtime info > > only on changed info (we can also hash it), > > It may put the placeholder in the DB first but it still relies on the data > > received from VDSM. > > if this table is only updated from vdsm to save it, i agree. > but isn't the engine also manipulating it? > wasn't there a request to be able to maybe edit the addresses some day?
Even if there was such a request, we still update when we receive the info from libvirt. Anyway there are obviously a few improvements to be done before caching. - update only when info received from VDSM change (need to verify it is the practice here) - do batch update for the new updated data received. - do the hashing (of vm device runtime info) on VDSM for the data , and update only when hash changes - caching ... Barak > > _______________________________________________ > Engine-devel mailing list > Engine-devel@ovirt.org > http://lists.ovirt.org/mailman/listinfo/engine-devel > > > _______________________________________________ Engine-devel mailing list Engine-devel@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel
