[rrd-users] RRDTool + libdbi + mysql + speed

[Brandon Phelps]

Just a wild guess here but have you checked memory usage during the 
job?  Maybe it has something to do with libdbi using mysql_store_result 
for such a large number of rows?  Try switching to mysql_use_result and 
see if the problem persists?

Just a thought, could be way off.

On 7/3/2011 10:14 PM, Adam Jacob Muller wrote:
> Hi,
> I'm curious if anyone knows of any specific issues with regards to libdbi and MySQL with RRDTool. I have a specific dataset where I pull a significant number of rows from MySQL to draw graphs (think, in the 100,000's of rows). And its extremely slow.
>
> I've specifically isolated this not to query execution time but to libdbi.
>
> to completely isolate the issue, this is a small program I wrote that uses libdbi to read a months worth of samples (~2*60*24*30 = 86400 rows):
>
>   # ./dbi
> dbi_conn_queryf took 0.5319
> dbi_result_next_row took 15.0172
> looped through 71891 rows
>   #
>
>
> This is the same thing, but using the native mysql c-bindings:
>   # ./mysql
> mysql_query took 0.0021
> mysql_fetch_row took 0.5352
> looped through 71891 rows
>   #
>
>
>
> This probably ultimately seems like a libdbi issue, but I thought i'd bring it up here because it seems to have an extraordinary impact upon rrdtool performance and i'm curious if anyone here has seen it.
>
>
> -Adam
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