[collectd] New plugin for collectd : write_mysql

Cyril Feraudet collectd at feraudet.com
Fri May 4 08:52:33 CEST 2012


Le 03.05.2012 20:05, Daniel Hilst a écrit : 

> On 05/03/2012 03:46
PM, Daniel Hilst wrote:
>> On 02/14/2012 09:54 AM, Cyril Feraudet
>>> Hi all, Here the write_mysql output plugin patch (from
5.0.2) with modifications suggested by Octo. By the way, notification
are handled, all memory used is freed on shutdown (thx Valgrind).
Regards, Cyril Le 04.01.2012 10:49, Cyril Feraudet a écrit : 
Hi Octo, Hi all, Thanks for your time. It will permit to me to improve
this plugin and my knowledge of C. Le 22.12.2011 01:06, Florian Forster
aécrit : 
>>>>> Hi Cyril, thank you very much for your patches!
I'm very sorry, but I can't give the plugin the thorough review it
deserves right now. But maybe you find the following comments helpful.
On Tue, Dec 20, 2011 at 03:03:43PM +0200, Cyril Feraudet wrote: 

>>>>>> - with_mysql_libs=`$with_mysql_config --libs 2>/dev/null` +
with_mysql_libs=`$with_mysql_config --libs_r 2>/dev/null`
>>>>> This
looks like a bug fix. Would it make sense to add this change to the 4.10
branch? If so, would you be willing to send a separate patch for
>>>> You are right, I will submit a patch soon. write_mysql is
often called than mysql plugin and non thread safe library make collectd
crashing quickly. 
>>>>>> +CREATE TABLE `data` ( + `id` bigint(20)
NOT NULL auto_increment, + `timestamp` double NOT NULL, + `host_id`
int(11) NOT NULL, + `plugin_id` int(11) NOT NULL, + `plugin_instance`
varchar(255) default NULL, + `type_id` int(11) NOT NULL, +
`typeinstance` varchar(255) default NULL, + `dataset_id` int(11) NOT
NULL, + `value` double NOT NULL,
>>>>> One of the reasons why I didn't
write a "write_dbi" or "write_mysql" plugin before is because I was
uncertain about the schema to use. Why did you chose to have a separate
table for host, plugin, plugin_instance, type, and type_instance? I
currently think that just having an "identifier" table with five columns
would be a better trade- off between normalization and complexity.
The idea was to save space in `data` table and improve querying in it.
For now, I've 800MB `data` table (MEMORY type) just for the last value
of each metrics (4207 servers / 462,395 metrics) using REPLACE instead
of INSERT statement. I think that SQL join are faster on numeric id than
varchar. But all of this things are questionable and dependent of the
final use. I think about a customizable SQL statement in plugin
configuration. diff --git a/src/write_mysql.c b/src/w /blockquote>
typedef struct host_s host_t; +struct host_s { + char 
>>>>>> t
(void) { + conn = mysql_init(NULL); + if (mysql_real_connect(conn, host,
user, passwd, database, port, NULL, 0) == NULL) { The conn
>>>>> be
(re-)established in the write() callback, when it is needed. Otherwise
you will never recover from connection failures. + if (!mysql_th
right, I just issued it. I will fix it too. { + ERROR("write_mysql
plugin: mysqlclient Thread Safe OFF"); I wasn't s function. Good to
>>>>> solid; margin-left:5px; width:100%">me) { [...] + len =
ssnprintf (query, sizeof (query), "SELECT id FROM host WHERE name =
'%s'", hostname); I think we should statement with bound arguments (or
whatever the terminology). This way (a) MySQL doesn't have to parse and
optimize the query each time we need to insert a host and (b) quoting is
done for us by the mysql library. +static
>>>> id (char * I will looking
for. I never used it before. t *ds, const value_list_t *vl, +
user_data_t __attribute__((unused)) *user_data) { [.
+ "VALUES (%.3f,%d,%d,'%s',%d,'%s',%d,%%lf)", CDTIME_T_TO_DOUBLE
(vl->time), host_id, + plugin_id, vl-&gt
>>>> nce, type_id,
vl->type_instance, dataset_id ); You really should prepare this
statement. Parsing this several thousand times per second will be a
major performance problem. +if (dso->type == DS_TYPE_GAUGE) { + len =
ssnprintf (query, sizeof (query), tmpquery, vl->values[i].gauge); +}

>>>>> = ssnprintf (query, sizeof (query), tmpquery, rates[i]); +}
+//INFO("toto: %d", toto); +pthread_mutex_lock(&mutex);
+DEBUG("write_mysql plugin: %s", query); +mysql_real_query(conn, query,
len); +pthread_mutex_unlock(&mutex); So you're inserting each data
source in a element? How can a client distinguish between the different
data sources? At least, you should add a "ds_index" column or so. Thanks
again and best There are dataset_id and type_id in `dataset` for that.
Here a query sample to get all metric in a type in right order : select
data.timestamp AS date, dataset.name AS dataset_name, data.value
>>>> m
data, host, plugin, type, dataset where host.id = data.host_id and
plugin.id = data.plugin_id and type.id = data.type_id and
data.dataset_id = dataset.id and host.name = 'eqds3pcold001' and
plugin.name = 'interface' and data.plugin_instance = 'eth0' and
type.name = 'if_octets' In my case, write_mysql is used to make, for
example, sum of cpu used on several thousand of server and re-inject
>>>>> mpagny allow me to share all my work on collectd in GPL
like licence. I will Release a beta of my unamed application soon a
possible. Regards, Cyril Feraudet
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>> Hello, I'm trying to compile collectd 5.0.2 with write_mysql
pluing I've done this: http://pastebin.com/dPc6zgUH [5] I'm on rhel 5.5
x86_64 Any idea?
> I have to run libtoolize --force before compile

> here is:
> tar vxf collectd-5.0.2.tar.bz2
> cd collectd-5.0.2
> patch
-p1 -i ../0001-Adding-write_mysql-output-plugin.patch
> aclocal
> automake
> libtoolize --force
> ./configure
> make
> make
install all
> Now I'm facing this error:
> error] write_mysql plugin:
Failed to bind param to statement : Statement 
> not prepared / INSERT
INTO data 

> (?,?,?,?,?,?,?,?)
> What that means????
> I tried Replace
"false" without success
> Thanks in advance,
> Hilst

This is an
old patch, please use this one : git clone -b cf/perfwatcher



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