Talk at the MySQL User Conference 2009 about extending MEM with new data collections, graphs and rules

1. Extending MEM,
Custom Advisors,
Graphs and Data
Collections
Mark Leith
Sun Microsystems
(leith@sun.com)

2. Agenda
 Quick MEM Agent Architecture
 Creating Data Collections
 Viewing Data Collection Information
 Creating Custom Graphs
 Creating and Modifying Advisors
 Questions / Input

3. Quick MEM Agent Architecture

4. Architecture – MEM Agent

5. Creating Data Collections

6. Data Collection Overview
 All Data Collections defined on each
Agent installation locally
 Defaults are within the
“./agent/share/mysql-proxy” directory
 SQL and Lua based collections
supported
 SQL statements defined in XML format
 QUAN based collections are all Lua via
the Proxy

7. Internal Data Collection Format
 Defined in XML files in the Advisor bundles
 Here's our definition of the
innodb_buffer_pool_size variable:
<itemList>
<attribName>innodb_buffer_pool_size</attribName>
<nameSpace>mysql</nameSpace>
<attribType>INTEGER</attribType>
<className>variables</className>
<categoryName>Memory</categoryName>
<subCategoryName>Buffers</subCategoryName>
<isCounter>false</isCounter>
</itemList>

8. Internal Data Collection Format
 Types: nameSpace::className::attribName
i.e: mysql::variables::innodb_buffer_pool_size or
os::cpu::cpu_user
 attribType – INTEGER | VARCHAR | DECIMAL
 isCounter – Whether the variable is a counter
(true) or point in time value (false)
 Counter based variables are always evaluated
using the delta between “now” and “now – 1”
collections
 Multiple instances of attributes supported
internally (for things such as CPUs, disks, etc.)
 Single instance collections use a “local” instance

9. SQL Based Data Collections
 Defaults in:
./agent/share/mysql-proxy/items/items-mysql-monitor.xml
<class>
<namespace>mysql</namespace>
<classname>classTitle</classname>
<query><![CDATA[SELECT ...]]></query>
</class>
 SELECT must return one row (others ignored
with warnings in the log file)
 Can return multiple columns in 2.x
● Assign <classname> in column order
 Note: <isCounter> is not available until 2.1 here

10. SQL Based Data Collections
 Collections can be added to the default, or a new file
 New files should be added to the agent-item-files
variable in the mysql-monitor-agent.ini file
 Let's try an example with the new
PERFORMANCE_SCHEMA!
<class>
<namespace>mysql</namespace>
<classname>wait_sum_open_mutex</classname>
<query><![CDATA[
SELECT sum_timer_wait
FROM PERFORMANCE_SCHEMA.EVENTS_WAITS_SUMMARY_BY_EVENT_NAME
WHERE EVENT_NAME = 'wait/synch/mutex/sql/LOCK_open'
]]></query>
</class>

11. Lua Based Data Collections
 Lua is a powerful embedded language – many
possibilities exist to collect data (running
external commands, gathering external data by
reading files, etc.)
 Lua collections also go to:
./agent/share/mysql-proxy/items/
 They should also be added to the agent-items-
files variable in the mysql-monitor-agent.ini file
 We build up the items, attributes and instances
as associative arrays within Lua

12. Basic Lua Collections
if not items then
items = { }
end
if not items.oldag then
items[quot;oldagquot;] = { }
end
items[quot;oldagquot;][quot;childrenquot;] = {
instances = { { name = quot;ethanquot; } },
attributes = {
[quot;couch-divesquot;] = {
returns = quot;intquot;
}
},
collector = function() return { [quot;couch-divesquot;] = math.random(100) + 120 } end
}

13. Matching Lua Arrays to Types
 The namespace is the top level of the items array
● “oldag”
 The classname / type name comes next
● “children”
 We then define the instances of the
namespace::classname by name
● “ethan”
 And the attributes and their return types
● “couchdives” returning an int
 Finally we define a collector function that pushes the
values we want to collect by attribute

14. Data Collections in the Dashboard
 Data collection metadata is stored in the
“inventory_*” tables
 inventory_namespaces (namespace info)
 inventory_types (maps to “classname”
information)
 inventory_attributes (attributes for
namespace::type)
 inventory_instances (the instance names of
each attribute)
 inventory_instance_attributes (pivot like table for
attributes to instances mappings)

15. Data Collections in the Dashboard
 A useful SQL statement to get DC information:
SELECT DISTINCT
namespace, type_name, attribute_name, instance_name
FROM inventory_namespaces iin,
inventory_types iit,
inventory_instance_attributes iia,
inventory_instances ii,
inventory_attributes ia
WHERE iia.instance_id = ii.instance_id
AND ii.type_id = iit.type_id
AND iin.namespace_id = iit.namespace_id
AND iia.attribute_id = ia.attribute_id;
*************************** 1. row ***************************
namespace: os
type_name: fs
attribute_name: fs_avail
instance_name: mac:{0025003d17370000}./

16. Data Collections in the Dashboard
 Actual data is stored within the “dc_ng_*” tables
 The collected data is stored in it's raw form, whether it
is a counter based variable or not
 Currently data is only purged, the infrastructure is
ready for aggregation and aging for historical data in
2.x (we want to test more!)
 dc_ng_long_now (integer based data)
 dc_ng_double_now (doubles)
 dc_ng_string_now (strings)
 dc_ng_(long|double)_age(0|1|2) (the rollup tables)
 String data obviously can not be aggregated

17. Data Collections in the Dashboard
 A useful SQL statement to get the collected data:
SELECT namespace, type_name, attribute_name, instance_name,
value, from_unixtime(end_time/1000)
FROM inventory_namespaces iin,
inventory_types iit,
dc_ng_long_now dcn,
inventory_instance_attributes iia,
inventory_instances ii,
inventory_attributes ia
WHERE dcn.instance_attribute_id = iia.instance_attribute_id
AND iia.instance_id = ii.instance_id
AND ii.type_id = iit.type_id
AND iin.namespace_id = iit.namespace_id
AND iia.attribute_id = ia.attribute_id
AND namespace = '...'
AND type_name = '...'
AND attribute_name = '...';

18. Creating Custom Graphs

19. Creating Custom Graphs
 Graphs also use XML for their structure
 Graphs can deal with both counter and non-counter
variables
 2.0 now allows you to import your own graphs:

20. Graph XML Template
<com_mysql_merlin_server_graph_Design>
<version>...</version> /* Internal graph version numbering */
<uuid>...</uuid> /* Internal graph unique identifier */
<tag>...</tag> /* Tags for the graph (will be exposed soon) */
<name>...</name> /* Visible graph name */
<rangeLabel>...</rangeLabel> /* Visible Y axis range label */
<series>
<label>...</label> /* Visible Series name / label */
<expression>...</expression> /* The expression used for the series */
</series>
<variables>
<name>...</name> /* Arbitrary name for variable in expression */
<dcItem>
<nameSpace>...</nameSpace>
<className>...</className>
<attribName>...</attribName>
</dcItem>
<instance>...</instance> /* The instance of the dc item to be used */
</variables>
</com_mysql_merlin_server_graph_Design>

21. Building a Graph - Metadata
 So let's build one up! Who wants to monitor disks?
 Start with the basic info
<com_mysql_merlin_server_graph_Design>
<version>1.0</version>
<uuid>a57c2bba-ea9b-102b-b396-94aca32bee28</uuid>
<name>filesystem usage - /</name>
<rangeLabel>MB</rangeLabel>
<frequency>00:05:00</frequency>
 Note <frequency>, this is not required, and defaults to
1 minute
 We use 5 minutes here to share with current collection

22. Building a Graph - Variables
 Next, skip to the end, and define the variables
<variables>
<name>used_fs</name>
<dcItem>
<nameSpace>os</nameSpace>
<className>fs</className>
<attribName>fs_used</attribName>
</dcItem>
<instance>/</instance>
</variables>
<variables>
<name>total_fs</name>
<dcItem>
<nameSpace>os</nameSpace>
<className>fs</className>
<attribName>fs_total</attribName>
</dcItem>
<instance>/</instance>
</variables>
</com_mysql_merlin_server_graph_Design>

23. Building a Graph - Series
 Now finally define each series
<series>
<label>used</label>
<expression>used_fs/1024/1024</expression>
</series>
<series>
<label>total size</label>
<expression>total_fs/1024/1024</expression>
</series>

24. View the Graph!

25. Graph PERFORMANCE_SCHEMA
 Viewing Global Mutex Information

26. Graph PERFORMANCE_SCHEMA
 Tracking Temporary File IO!

27. Graphs – Current Caveats
 Currently only line graphs are supported
 Graphs are shared across all servers – so
they will show up even if the
instances/collections are not available on a
specific server
 Graphs sort alphabetically – if you want
custom graphs to sort together, keep that in
mind
 There is no “Delete” for graphs

28. Creating and Modifying Advisors

29. Modifying Current Rules
 All of the current rules are conservative – they
should certainly be modified to your environment
 You can edit current rues on the “Manage Rules”
page within the Advisors tab
 Editing only allows you to modify the
THRESHOLD and frequency values for the rule
 Copying allows you to alter the expression, and
advice or problem descriptions etc., as well as
add new variables

30. Modifying Current Rules

31. Creating New Rules
 Also done on the Manage Rules page
 Any data collection can be used in a rule, with no limit
on the number of data collections that can be used
 We still only support the default 3 THRESHOLD values
– Info / Warning / Critical
 Wrapping the variable names in %percents% allows us
to do variable value substitution within the Advice and
Recommended Action sections
 We can also format numerical output nicely with
'{'formatNumber:%variable_name%'}'
 You can make parts bold with two underscores on
either side of a section of the advice etc. too

32. Creating New Rules

33. Creating New Rules

34. Creating New Rules
 Once saved, you will be able to schedule the rule
within the Advisors->Add to Schedule page

35. Questions?
 Ask me now!
 Join us at the “Stump the DBA” BoF
tonight
 Ask a MySQL Support Engineer
http://support.mysql.com