From 780732d2129e2738ce25d225f6046e44142b69dc Mon Sep 17 00:00:00 2001
From: Tomas Kopecek <tkopecek@redhat.com>
Date: Oct 03 2019 10:33:06 +0000
Subject: Subselect gives better performance


Original query based on JOINs is 1000x slower in better cases. Sub-query
helps a lot here.

Fixes: https://pagure.io/koji/issue/1674

---

diff --git a/hub/kojihub.py b/hub/kojihub.py
index 6a9711d..b453a1d 100644
--- a/hub/kojihub.py
+++ b/hub/kojihub.py
@@ -7389,10 +7389,13 @@ def build_references(build_id, limit=None, lazy=False):
     fields = ('id', 'name', 'version', 'release', 'arch', 'build_id')
     idx = {}
     q = """SELECT rpminfo.id, rpminfo.name, rpminfo.version, rpminfo.release, rpminfo.arch, rpminfo.build_id
-    FROM buildroot_listing
-        JOIN rpminfo ON rpminfo.buildroot_id = buildroot_listing.buildroot_id
-        JOIN build on rpminfo.build_id = build.id
-    WHERE buildroot_listing.rpm_id = %(rpm_id)s
+    FROM rpminfo, build
+    WHERE
+        rpminfo.buildroot_id IN (
+            SELECT DISTINCT buildroot_id
+                FROM buildroot_listing
+                WHERE rpm_id = %(rpm_id)s)
+        AND rpminfo.build_id = build.id
         AND build.state = %(st_complete)i"""
     if limit is not None:
         q += "\nLIMIT %(limit)i"