From: Tom Clegg <tom@curoverse.com>
Date: Fri, 16 Jun 2017 13:34:08 +0000 (-0400)
Subject: 11283: Add explanatory comment to SQL query.
X-Git-Tag: 1.1.0~190^2
X-Git-Url: https://git.arvados.org/arvados.git/commitdiff_plain/7409b2f682d562cd7ef7bcf558597ae2181ea7c1

11283: Add explanatory comment to SQL query.

Arvados-DCO-1.1-Signed-off-by: Tom Clegg <tom@curoverse.com>
---

diff --git a/services/api/app/models/node.rb b/services/api/app/models/node.rb
index e1c1e64914..8eb40f9fbb 100644
--- a/services/api/app/models/node.rb
+++ b/services/api/app/models/node.rb
@@ -139,6 +139,9 @@ class Node < ArvadosModel
   protected
 
   def self.available_slot_number
+    # Join the sequence 1..max with the nodes table. Return the first
+    # (i.e., smallest) value that doesn't match the slot_number of any
+    # existing node.
     connection.exec_query('SELECT n FROM generate_series(1, $1) AS slot(n)
                           LEFT JOIN nodes ON n=slot_number
                           WHERE slot_number IS NULL