From: Sebastian Harl <sh@tokkee.org>
Date: Sat, 7 Mar 2009 16:43:54 +0000 (+0100)
Subject: postgresql_default.conf: Make sure the "disk_io" query does not return NULLs.
X-Git-Tag: collectd-4.6.2~5^2
X-Git-Url: https://git.tokkee.org/?a=commitdiff_plain;h=54fb57fbc5658fc3d150219d07d840178d64d087;p=collectd.git

postgresql_default.conf: Make sure the "disk_io" query does not return NULLs.

Starting with some version between 8.3.3 and 8.3.6, pg_statio_*_tables returns
NULL instead of 0 for statistics if no instance of the appropriate relation
exists. PQgetvalue() returns an empty string in that case which would then
result in error messages when udb_result_submit() tries to convert that to a
number.

Now, the "disk_io" query uses PostgreSQL's coalesce() function to make sure 0
is returned instead of NULL.
---

diff --git a/src/postgresql_default.conf b/src/postgresql_default.conf
index 61844a02..5b024ca1 100644
--- a/src/postgresql_default.conf
+++ b/src/postgresql_default.conf
@@ -67,10 +67,14 @@
 </Query>
 
 <Query disk_io>
-	Query "SELECT sum(heap_blks_read), sum(heap_blks_hit), \
-			sum(idx_blks_read), sum(idx_blks_hit), \
-			sum(toast_blks_read), sum(toast_blks_hit), \
-			sum(tidx_blks_read), sum(tidx_blks_hit) \
+	Query "SELECT coalesce(sum(heap_blks_read), 0), \
+			coalesce(sum(heap_blks_hit), 0), \
+			coalesce(sum(idx_blks_read), 0), \
+			coalesce(sum(idx_blks_hit), 0), \
+			coalesce(sum(toast_blks_read), 0), \
+			coalesce(sum(toast_blks_hit), 0), \
+			coalesce(sum(tidx_blks_read), 0), \
+			coalesce(sum(tidx_blks_hit), 0) \
 		FROM pg_statio_user_tables;"
 
 	Column pg_blks heap_read
@@ -91,3 +95,5 @@
 	Column pg_db_size
 </Query>
 
+# vim: set ft=config :
+