Graphs showing wrong values...

[AdrianS]

Hi,

I'v notice a strange problem with graphs (1.4.1) - when showing more then few days (only with some graphs), shown data are completely inaccurate. When I choose to show last values of specific period - everything is ok.

Here is an example
This is OK 3 days graph


This is wrong 4 days graph (should be like before till 20 July ~4TB and after 6TB)


And here are values for period of last graph (4 days)

Any idea what can be wrong - is this bug known already?
--
Regards
Adrian (Sauron) Siemieniak /,/ .. Who can destroy The Thing,
sauron{at}rpg{dot}pl /`/ controls The Thing ... (DUNE)

[Alexei]

Thanks for reporting this. This is more serious problem than it looks. Basically it is related to a limited precision of values stored in the table 'trends'. It will be fixed in 1.6. Unfortunately it cannot be fixed in 1.4.x because database patching is required.

[AdrianS]

So it is enough to do
ALTER TABLE `trends` CHANGE `value_min` `value_min` DOUBLE( 18, 4 ) NOT NULL DEFAULT '0.0000';
ALTER TABLE `trends` CHANGE `value_avg` `value_avg` DOUBLE( 18, 4 ) NOT NULL DEFAULT '0.0000';
ALTER TABLE `trends` CHANGE `value_max` `value_max` DOUBLE( 18, 4 ) NOT NULL DEFAULT '0.0000';

and erase/change wrong data in "trends" table? Or there is also some limitation in aggregating formula in zabbix?

ps. value 18,4 is just for example - for this case should be enough

[AdrianS]

Ok I'v checked and it's working - in this case it was easy to fix all data in trends (for this itemid) , because there was only one change of it in entire history .

I think it should be fixed before 1.6, since leaving it this way, simply can corrupts data - which can't be fixed later. This simple sql query (to change double precision) took on my trends table (about 5426605 values) less then a minute.

[Alexei]

I'm thinking of adding an extra table into 1.6, trends_uint for keeping trends of 64 bit unsigned integer data.