[collectd] Queries with `sum(something) as this' don't work on dbi plugin (SQLServer)

[Daniel Hilst]

On 02-04-2013 12:19, Daniel Hilst Selli wrote:
> I'm facing this error
>
> [2013-04-02 12:13:21] [error] dbi plugin: Column `log_reads': Don't know
> how to handle source type 4.
> [2013-04-02 12:13:21] [error] dbi plugin: cdbi_read_database_query
> (MSSQLServer, teste_query): cdbi_result_get_field (1) failed.
>
> While using this dbi block
> <Plugin dbi>
>          <Query "teste_query">
>                  Statement "select sum(total_logical_reads) as log_reads
> from sys.dm_exec_query_stats"
>                  <Result>
>                          Type "gauge"
>                          ValuesFrom "log_reads"
>                  </Result>
>          </Query>
>
>          <Database "MSSQLServer">
>                  Driver "freetds"
>                  Hostname "orisnet.verzani.com.br"
>                  DriverOption "host" "192.168.5.18"
>                  DriverOption "username" "SA"
>                  DriverOption "password" "Paxazx01"
>                  Query "teste_query"
>          </Database>
> </Plugin>
>
> The problem is with things like this `sum(something) as this' I just
> can't get it working.. The query works fine on SSMS and retruns only one
> line and one column,  Any idea?
>
> PS: I'm trying to monitor the reads/writes and worker time on MS
> SQLServer..
>
> Regards,
>


I track the problem...
This message
'dbi plugin: Column `log_reads': Don't know how to handle source type 4'
Comes from here [1]. Seems that libdbi is returning something unexpected 
by dbi plugin.

The type for stands for DBI_TYPE_BINARY here [2] line 114

[1] https://github.com/collectd/collectd/blob/master/src/dbi.c#L132
[2] 
http://libdbi.cvs.sourceforge.net/viewvc/libdbi/libdbi/include/dbi/dbi.h.in?revision=1.13&view=markup 
line 114


So, I think, SUM() would return integer types, but for libdbi, don't, 
I'm digging deeper on this..

:-)

-- 
Follow the white rabbit!