Remove disjunction in pkg_providers query

For some reason, running the SELECT .. WHERE .. OR .. query takes e.g.
58ms on a randomly generated db for some dependency name. Splitting the
OR into two dedicated queries and UNIONing the result takes only 0.42ms.

On the Arch Linux installation, searching for the providers of e.g.
mongodb takes >=110ms when not cached by the query cache. The new query
takes <1ms even when not cached.

Signed-off-by: Florian Pritz <bluewind@xinu.at>
Signed-off-by: Lukas Fleischer <lfleischer@archlinux.org>
This commit is contained in:
Florian Pritz 2018-02-21 15:49:05 +01:00 committed by Lukas Fleischer
parent 34a0d39910
commit f51d4c32cd

View file

@ -212,10 +212,12 @@ function pkg_groups($pkgid) {
function pkg_providers($name) { function pkg_providers($name) {
$dbh = DB::connect(); $dbh = DB::connect();
$q = "SELECT p.ID, p.Name FROM Packages p "; $q = "SELECT p.ID, p.Name FROM Packages p ";
$q.= "WHERE p.Name = " . $dbh->quote($name) . " ";
$q.= "UNION ";
$q.= "SELECT p.ID, p.Name FROM Packages p ";
$q.= "LEFT JOIN PackageRelations pr ON pr.PackageID = p.ID "; $q.= "LEFT JOIN PackageRelations pr ON pr.PackageID = p.ID ";
$q.= "LEFT JOIN RelationTypes rt ON rt.ID = pr.RelTypeID "; $q.= "LEFT JOIN RelationTypes rt ON rt.ID = pr.RelTypeID ";
$q.= "WHERE p.Name = " . $dbh->quote($name) . " "; $q.= "WHERE (rt.Name = 'provides' ";
$q.= "OR (rt.Name = 'provides' ";
$q.= "AND pr.RelName = " . $dbh->quote($name) . ")"; $q.= "AND pr.RelName = " . $dbh->quote($name) . ")";
$q.= "UNION "; $q.= "UNION ";
$q.= "SELECT 0, Name FROM OfficialProviders "; $q.= "SELECT 0, Name FROM OfficialProviders ";