yahoo-eng-team team mailing list archive

[Matt Riedemann <mriedem.os@xxxxxxxxx>]

Public bug reported:

During a resize_claim the ResourceTracker lazy-loads in 3 separate calls
to the DB (over RPC) these 3 fields:

    b"2019-11-20 16:13:29,521 DEBUG [nova.objects.instance] Lazy-loading 'pci_requests' on Instance uuid c0fdac69-b360-4526-917e-16fb018cb8a3"
    b"2019-11-20 16:13:29,525 DEBUG [nova.objects.instance] Lazy-loading 'resources' on Instance uuid c0fdac69-b360-4526-917e-16fb018cb8a3"
    b"2019-11-20 16:13:29,527 DEBUG [nova.objects.instance] Lazy-loading 'pci_devices' on Instance uuid c0fdac69-b360-4526-917e-16fb018cb8a3"

It seems we should be able to collapse that into a single DB call to
load the necessary fields in a single call.

We could add a new extra_attrs kwarg to the Instance.refresh method so
we can keep using the same instance we have in memory (and is shared by
the ComputeManager method calling the resize_claim) or we could add a
new load_if_not_present() method to the Instance object. I'm not sure if
there are pros/cons either way on using refresh or adding a new method.

** Affects: nova
     Importance: Low
         Status: Confirmed


** Tags: performance resize

** Changed in: nova
       Status: New => Confirmed

** Changed in: nova
   Importance: Undecided => Low

-- 
You received this bug notification because you are a member of Yahoo!
Engineering Team, which is subscribed to OpenStack Compute (nova).
https://bugs.launchpad.net/bugs/1853370

Title:
  resize_claim lazy-loads at least 3 joined fields in separate DB calls

Status in OpenStack Compute (nova):
  Confirmed

Bug description:
  During a resize_claim the ResourceTracker lazy-loads in 3 separate
  calls to the DB (over RPC) these 3 fields:

      b"2019-11-20 16:13:29,521 DEBUG [nova.objects.instance] Lazy-loading 'pci_requests' on Instance uuid c0fdac69-b360-4526-917e-16fb018cb8a3"
      b"2019-11-20 16:13:29,525 DEBUG [nova.objects.instance] Lazy-loading 'resources' on Instance uuid c0fdac69-b360-4526-917e-16fb018cb8a3"
      b"2019-11-20 16:13:29,527 DEBUG [nova.objects.instance] Lazy-loading 'pci_devices' on Instance uuid c0fdac69-b360-4526-917e-16fb018cb8a3"

  It seems we should be able to collapse that into a single DB call to
  load the necessary fields in a single call.

  We could add a new extra_attrs kwarg to the Instance.refresh method so
  we can keep using the same instance we have in memory (and is shared
  by the ComputeManager method calling the resize_claim) or we could add
  a new load_if_not_present() method to the Instance object. I'm not
  sure if there are pros/cons either way on using refresh or adding a
  new method.

To manage notifications about this bug go to:
https://bugs.launchpad.net/nova/+bug/1853370/+subscriptions