Piotr Kliczewski has submitted this change and it was merged. Change subject: database: memory_and_disk_images_storage_domain_view ...................................................................... database: memory_and_disk_images_storage_domain_view Inline EXISTS conditions in a select list, should, in theory perform a query once per row of the select list, while moving the same logic to a LEFT JOIN should allow the database to perform the query just once and hash-join it, resulting in a performance improvement. This patch also adds the missing indexes on the snapshots table to make these joins efficient. According to the work done on verifying bug #1302752, on a loaded system with 500 hosts, 7K VMs and 3 disks per VM, this patch improves the query's runtime by a factor of 33 - from 6600 msecs to 200 msecs. Change-Id: Ifbedd49da10fa6752234eacf72bbb0f350b3c778 Bug-Url: https://bugzilla.redhat.com/1363823 Bug-Url: https://bugzilla.redhat.com/1302752 Signed-off-by: Allon Mureinik <amureini(a)redhat.com&gt; --- M packaging/dbscripts/create_views.sql A packaging/dbscripts/upgrade/04_00_0860_memory_and_disk_images_storage_domain_view_join_indexes.sql 2 files changed, 13 insertions(+), 17 deletions(-) Approvals: Martin Peřina: Looks good to me, approved Jenkins CI: Passed CI tests Allon Mureinik: Verified -- To view, visit https://gerrit.ovirt.org/62286 To unsubscribe, visit https://gerrit.ovirt.org/settings Gerrit-MessageType: merged Gerrit-Change-Id: Ifbedd49da10fa6752234eacf72bbb0f350b3c778 Gerrit-PatchSet: 2 Gerrit-Project: ovirt-engine Gerrit-Branch: ovirt-engine-4.0 Gerrit-Owner: Allon Mureinik <amureini(a)redhat.com&gt; Gerrit-Reviewer: Allon Mureinik <amureini(a)redhat.com&gt; Gerrit-Reviewer: Arik Hadas <ahadas(a)redhat.com&gt; Gerrit-Reviewer: Jenkins CI Gerrit-Reviewer: Martin Peřina <mperina(a)redhat.com&gt; Gerrit-Reviewer: Piotr Kliczewski <piotr.kliczewski(a)gmail.com&gt; Gerrit-Reviewer: Tal Nisan <tnisan(a)redhat.com&gt; Gerrit-Reviewer: gerrit-hooks <automation(a)ovirt.org&gt;