Liron Ar has submitted this change and it was merged. Change subject: core: avoid deadlock in images ...................................................................... core: avoid deadlock in images Currently the images table contains a foreign key to itself (quoting from the table definition) : ... TABLE "images" CONSTRAINT "image_templates_images" FOREIGN KEY (it_guid) REFERENCES images(image_guid) ... The column it_guid in the images table indicates what is the template that the image is based on. In postgres versions earlier than 9.3, when executing a update to a row with a foreign key, a lock on the referenced record is taken which means that we have a chance for a deadlock in the following scenarios: 1. Simultenous update to the template disks and to the disks of a vm based on the template. 2. Simultenous update to disks of vms based on the same template. This issue has been resolved in postgres 9.3 (http://www.postgresql.org/docs/9.3/static/release-9-3.html see E.5.3.1.1), till we'll enforce usage of that version we can drop that foreign key constraint which will also align it with the parentid column that we don't a FK on as well. Regardless of that, we should remove unneeded updates to images in different flows. Change-Id: Ib4939a716cef8901b53a90499201d815a4e3cb58 Bug-Url: https://bugzilla.redhat.com/1077715 Signed-off-by: Liron Aravot <laravot(a)redhat.com&gt; --- A packaging/dbscripts/upgrade/03_05_0600_drop_images_fk.sql 1 file changed, 1 insertion(+), 0 deletions(-) Approvals: Liron Ar: Verified; Looks good to me, approved -- To view, visit http://gerrit.ovirt.org/28409 To unsubscribe, visit http://gerrit.ovirt.org/settings Gerrit-MessageType: merged Gerrit-Change-Id: Ib4939a716cef8901b53a90499201d815a4e3cb58 Gerrit-PatchSet: 4 Gerrit-Project: ovirt-engine Gerrit-Branch: master Gerrit-Owner: Liron Ar <laravot(a)redhat.com&gt; Gerrit-Reviewer: Allon Mureinik <amureini(a)redhat.com&gt; Gerrit-Reviewer: Daniel Erez <derez(a)redhat.com&gt; Gerrit-Reviewer: Liron Ar <laravot(a)redhat.com&gt; Gerrit-Reviewer: Maor Lipchuk <mlipchuk(a)redhat.com&gt; Gerrit-Reviewer: automation(a)ovirt.org Gerrit-Reviewer: oVirt Jenkins CI Server