[Bug 1850754] [NEW] ceph-volume lvm list is O(n^2)

[Dariusz Gadomski]

Public bug reported:

ceph-volume lvm list calls take very long time due to the fact it has
been implemented with O(n^2). This leads to unproportionally long
execution time taking under consideration the fact that no complex
computation is needed.

Steps to reproduce:
1. Create a setup with a large number of disks and logical volumes (e.g. 24)
2. Call ceph-volume lvm list for one of the disks.
3. Wait for the call to finish.

Expected result:
Call is executed within seconds at most.

Actual result:
Call may take even minutes in some circumstances (large number of disks, some OSDs stopped).

** Affects: ceph
     Importance: Unknown
         Status: Unknown

** Affects: ceph (Ubuntu)
     Importance: Undecided
     Assignee: Dariusz Gadomski (dgadomski)
         Status: New

** Bug watch added: tracker.ceph.com/issues #37490
   http://tracker.ceph.com/issues/37490

** Also affects: ceph via
   http://tracker.ceph.com/issues/37490
   Importance: Unknown
       Status: Unknown

** Changed in: ceph (Ubuntu)
     Assignee: (unassigned) => Dariusz Gadomski (dgadomski)

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https://bugs.launchpad.net/bugs/1850754

Title:
  ceph-volume lvm list is O(n^2)

Status in Ceph:
  Unknown
Status in ceph package in Ubuntu:
  New

Bug description:
  ceph-volume lvm list calls take very long time due to the fact it has
  been implemented with O(n^2). This leads to unproportionally long
  execution time taking under consideration the fact that no complex
  computation is needed.

  Steps to reproduce:
  1. Create a setup with a large number of disks and logical volumes (e.g. 24)
  2. Call ceph-volume lvm list for one of the disks.
  3. Wait for the call to finish.

  Expected result:
  Call is executed within seconds at most.

  Actual result:
  Call may take even minutes in some circumstances (large number of disks, some OSDs stopped).

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