From 520c8a58267a4c405b6ac47f853a66c729f761a5 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Wed, 16 Mar 2016 13:41:43 +0100
Subject: [PATCH] Use faster query to determine number of running builds

The previous query

  select count(*) from builds b left join buildsteps s on s.build = b.id where busy = 1 and finished = 0

is suddenly taking several minutes. Probably PostgreSQL decided to use
a suboptimal query plan.
---
 src/lib/Hydra/Controller/Root.pm | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/lib/Hydra/Controller/Root.pm b/src/lib/Hydra/Controller/Root.pm
index 5070c090..722de6e4 100644
--- a/src/lib/Hydra/Controller/Root.pm
+++ b/src/lib/Hydra/Controller/Root.pm
@@ -45,9 +45,8 @@ sub begin :Private {
     }
 
     if (scalar(@args) == 0 || $args[0] ne "static") {
-        $c->stash->{nrRunningBuilds} = $c->model('DB::Builds')->search(
-            { finished => 0, 'buildsteps.busy' => 1 },
-            { join => 'buildsteps', select => ["id"], distinct => 1 })->count();
+        $c->stash->{nrRunningBuilds} = $c->model('DB')->schema->storage->dbh->selectrow_array(
+            "select count(distinct build) from buildsteps where busy = 1");
         $c->stash->{nrQueuedBuilds} = $c->model('DB::Builds')->search({ finished => 0 })->count();
     }