Allon Mureinik has submitted this change and it was merged. Change subject: core: GetUnregisteredCinderDisksByStorageDomainIdQuery performance ...................................................................... core: GetUnregisteredCinderDisksByStorageDomainIdQuery performance GetUnregisteredCinderDisksByStorageDomainIdQuery had a naive implementation to compare between the volumes retrieved from Cinder and the disks stored in the engine database. In the old implementation, a list of all the volumes was retrieved from the Cinder provider (denoted as N volumes from now on) and a list of all the disks in a given Cinder domain were retrieved from the database (denoted as M disks from now on). Then the volumes were iterated over, and for each volume, the disks were iterated over, in search of a disk with a corresponding ID, resulting in an algorithm with an O(N * M) time complexity. In the implementation presented by this patch, the disks are first iterated, and a Set of their IDs is produced (An O(N) operation). Then, the volumes are iterated, and filtered according their ID being present in the aforementioned Set (An O(M) operation, assuming the JDK implements an efficient hash on Strings). The resulting algorithm has an O(N+M) time complexity, and given n->inf, m->inf, should present a significant improvement in large systems. As an added bonus, this algorithm is implemented using Java 8's built-in streaming APIs instead of the boiler-plated, ugly, LinqUtils code. Change-Id: I5fb243998255cac1936ac388729f3f933a9320e2 Signed-off-by: Allon Mureinik <amureini@redhat.com> --- M backend/manager/modules/bll/src/main/java/org/ovirt/engine/core/bll/storage/GetUnregisteredCinderDisksByStorageDomainIdQuery.java 1 file changed, 5 insertions(+), 13 deletions(-) Approvals: Tal Nisan: Looks good to me, but someone else must approve Allon Mureinik: Verified; Passed CI tests Maor Lipchuk: Looks good to me, approved -- To view, visit https://gerrit.ovirt.org/48656 To unsubscribe, visit https://gerrit.ovirt.org/settings Gerrit-MessageType: merged Gerrit-Change-Id: I5fb243998255cac1936ac388729f3f933a9320e2 Gerrit-PatchSet: 4 Gerrit-Project: ovirt-engine Gerrit-Branch: master Gerrit-Owner: Allon Mureinik <amureini@redhat.com> Gerrit-Reviewer: Allon Mureinik <amureini@redhat.com> Gerrit-Reviewer: Daniel Erez <derez@redhat.com> Gerrit-Reviewer: Jenkins CI Gerrit-Reviewer: Maor Lipchuk <mlipchuk@redhat.com> Gerrit-Reviewer: Tal Nisan <tnisan@redhat.com> Gerrit-Reviewer: gerrit-hooks <automation@ovirt.org>