<div dir="ltr"><div><div><div><div>Hello List,<br><br></div>I migrated my growing collection of RRD files to MySQL several months ago and it really reduced the IO load on the data collecting host as well as improved the speed of drawing graphs. A new problem I faced was that the length of rrdgraph commands increased due to longer DEF statements - with sql/ notation on average the length of a single DEF statement is about 250 characters. I have scripts that generate rrdgraph commands to draw complex graphs with tens or sometimes hundreds of DEFs, CDEFs, GPRINTs for formatted legends etc. and many times it happened that rrdgraph failed to generate a picture, because the command was too long (the length limit on my system is 130k characters). It would help to avoid this issue and shorten the command length if it was possible to define a DSN (Data Source Name) and reuse it in DEFs, ie.:<br>
<br></div>rrdtool graph ... \<br></div>DSN:dsn1=sql//mysql/host=<a href="http://mysql1.example.com/port=3306/dbname=mydb/username=dbuser/password=dbpassword">mysql1.example.com/port=3306/dbname=mydb/username=dbuser/password=dbpassword</a> \<br>
... \<br></div>DEF:defA=dsn1/rrdminstepsize=60/TABLE_A/timestamp/value/RRDKeyID='"keyA'":avg:AVERAGE \<br>DEF:defB=dsn1/rrdminstepsize=60/TABLE_B/timestamp/value/RRDKeyID='"keyB'":avg:AVERAGE \<br>
DEF:defC=dsn1/rrdminstepsize=60/TABLE_C/timestamp/value/RRDKeyID='"keyC'":avg:AVERAGE \<br>...<br clear="all"><div><div><div><div><div><div><br></div><div>It's debatable what elements should be included in DSN and what should be left for DEF, however I would suggest that DSN only contained host, port, dbname, dbuser and password, because one database can have multiple tables with different step sizes, so the in DEFs it would be possible to use different tables in the same DB referring to the same DSN, but giving different step sizes and table names.<br>
<br></div><div>Another feature that I think would be very useful is reading DSN from files: store DSN definition in a text file and then point to this file in the command, ie.:<br><br></div><div>rrdtool graph ... \<br></div>
<div>DSN:dsn1=file:///path/to/file \<br>...<br><br></div><div>This way DB credentials would be better protected as there would be no risk that they appear in the commands and later in application logs or elsewhere in the system where other users could see them.<br>
<br></div><div>Please share your thoughts and comments on this feature.<br></div><div><br>--<br>Regards,<br>Maciek Kolbusz</div>
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