Trying to improve Query Cache Memory graph

[jeroenvermeulen]

Hi @kjellm
I am trying to improve the Query Cache Memory graph by:

• Adding 'used memory' (cdef)
• Stacking 'free memory' on top of 'used memory'
• Using better colours

The problem I am having is the CDEF is not working because of this Munin bug:
http://munin-monitoring.org/ticket/1352
This bug only applies to field names longer than 15 chars.
What do you think is the best solution or workaround?

Maybe we should trim all fields to 15 chars?

[jeroenvermeulen]

Some moments it works, others it doesn't. When it works it looks like this:

[jeroenvermeulen]

Then error when it doesn't work:

==> /var/log/munin/munin-cgi-graph.log <==
2017/08/04 16:01:31 [RRD ERROR] Unable to graph /var/lib/munin/cgi-tmp/munin-cgi-graph/magehost.pro/rock.magehost.pro/mysql_qcache_mem-pinpoint=1501747086,1501855086.png?&lower_limit=&upper_limit=&size_x=800&size_y=400 : don't understand 'aQcache_free_memory,-'
2017/08/04 16:01:31 [RRD ERROR] rrdtool 'graph' '/var/lib/munin/cgi-tmp/munin-cgi-graph/magehost.pro/rock.magehost.pro/mysql_qcache_mem-pinpoint=1501747086,1501855086.png?&lower_limit=&upper_limit=&size_x=800&size_y=400' \
	'--title' \
	'Query Cache Memory - from Thu Aug  3 09:58:06 2017 to Fri Aug  4 15:58:06 2017' \
	'--start' \
	'1501747086' \
	'--end' \
	'1501855086' \
	'--base' \
	'1024' \
	'--lower-limit' \
	'0' \
	'--no-gridfit' \
	'--slope-mode' \
	'--vertical-label' \
	'Bytes' \
	'--slope-mode' \
	'--height' \
	'400' \
	'--width' \
	'800' \
	'--imgformat' \
	'PNG' \
	'--font' \
	'DEFAULT:0:DejaVuSans,DejaVu Sans,DejaVu LGC Sans,Bitstream Vera Sans' \
	'--font' \
	'LEGEND:7:DejaVuSansMono,DejaVu Sans Mono,DejaVu LGC Sans Mono,Bitstream Vera Sans Mono,monospace' \
	'--color' \
	'BACK#F0F0F0' \
	'--color' \
	'FRAME#F0F0F0' \
	'--color' \
	'CANVAS#FFFFFF' \
	'--color' \
	'FONT#666666' \
	'--color' \
	'AXIS#CFD6F8' \
	'--color' \
	'ARROW#CFD6F8' \
	'--border' \
	'0' \
	'-W' \
	'Munin 2.0.25-2ubuntu0.16.04.3' \
	'DEF:a5e605d6a03f5ee1=/var/lib/munin/magehost.pro/rock.magehost.pro-mysql_qcache_mem-Qcache_free_memory-g.rrd:42:MAX' \
	'DEF:i5e605d6a03f5ee1=/var/lib/munin/magehost.pro/rock.magehost.pro-mysql_qcache_mem-Qcache_free_memory-g.rrd:42:MIN' \
	'DEF:g5e605d6a03f5ee1=/var/lib/munin/magehost.pro/rock.magehost.pro-mysql_qcache_mem-Qcache_free_memory-g.rrd:42:AVERAGE' \
	'DEF:acebc72e866d3a46=/var/lib/munin/magehost.pro/rock.magehost.pro-mysql_qcache_mem-Qcache_used_memory-g.rrd:42:MAX' \
	'DEF:icebc72e866d3a46=/var/lib/munin/magehost.pro/rock.magehost.pro-mysql_qcache_mem-Qcache_used_memory-g.rrd:42:MIN' \
	'DEF:gcebc72e866d3a46=/var/lib/munin/magehost.pro/rock.magehost.pro-mysql_qcache_mem-Qcache_used_memory-g.rrd:42:AVERAGE' \
	'DEF:a380b7434f06c805=/var/lib/munin/magehost.pro/rock.magehost.pro-mysql_qcache_mem-query_cache_size-g.rrd:42:MAX' \
	'DEF:i380b7434f06c805=/var/lib/munin/magehost.pro/rock.magehost.pro-mysql_qcache_mem-query_cache_size-g.rrd:42:MIN' \
	'DEF:g380b7434f06c805=/var/lib/munin/magehost.pro/rock.magehost.pro-mysql_qcache_mem-query_cache_size-g.rrd:42:AVERAGE' \
	'CDEF:c380b7434f06c805=g380b7434f06c805' \
	'COMMENT:          ' \
	'COMMENT: Cur\:' \
	'COMMENT:Min\:' \
	'COMMENT:Avg\:' \
	'COMMENT:Max\:  \j' \
	'LINE1:g380b7434f06c805#000000:Cache size ' \
	'GPRINT:c380b7434f06c805:LAST:%7.2lf%s' \
	'GPRINT:i380b7434f06c805:MIN:%7.2lf%s' \
	'GPRINT:g380b7434f06c805:AVERAGE:%7.2lf%s' \
	'GPRINT:a380b7434f06c805:MAX:%7.2lf%s\j' \
	'CDEF:ad2d11b2421088e4=a380b7434f06c805,aQcache_free_memory,-' \    <== not replaced
	'CDEF:id2d11b2421088e4=i380b7434f06c805,iQcache_free_memory,-' \    <== not replaced
	'CDEF:gd2d11b2421088e4=g380b7434f06c805,gQcache_free_memory,-' \    <== not replaced
	'CDEF:cd2d11b2421088e4=gd2d11b2421088e4' \
	'AREA:gd2d11b2421088e4#8d01ba:Used mem   ' \
	'GPRINT:cd2d11b2421088e4:LAST:%7.2lf%s' \
	'GPRINT:id2d11b2421088e4:MIN:%7.2lf%s' \
	'GPRINT:gd2d11b2421088e4:AVERAGE:%7.2lf%s' \
	'GPRINT:ad2d11b2421088e4:MAX:%7.2lf%s\j' \
	'CDEF:c5e605d6a03f5ee1=g5e605d6a03f5ee1' \
	'STACK:g5e605d6a03f5ee1#96e789:Free mem   ' \     <== is replaced
	'GPRINT:c5e605d6a03f5ee1:LAST:%7.2lf%s' \
	'GPRINT:i5e605d6a03f5ee1:MIN:%7.2lf%s' \
	'GPRINT:g5e605d6a03f5ee1:AVERAGE:%7.2lf%s' \
	'GPRINT:a5e605d6a03f5ee1:MAX:%7.2lf%s\j' \
	'VRULE:1501855200#999999' \
	'COMMENT:Last update\: Fri Aug  4 16\:00\:00 2017\r'