5. Viewing Data

emt_view is the main script used to view data stored in a local output handler. With emt_view you can specify individual fields to comopare or predefined groups of fields called views. By default emt_view will display the default_view defined under [emt_view] in the emt.cnf configuration file.

emt_view can take a list of fields to display. These are specified using the -f flag in the format instance:field.sub_field. Instance and sub_field are optional and field is required. Viewing multiple fields is possible by separating them with a comma. The timestamp field is always specified so you don't have to include it. For example to view just mysql select query counts.

ebergen@etna:(~) emt_view -f mysql_com.select

[------emt------] [mysql-] 
Timestamp         Com      
                  select   
 2009-04-03 16:11  28      
 2009-04-03 16:12  94      
 2009-04-03 16:13  27      
 2009-04-03 16:14  46      
 2009-04-03 16:15  67  

To view multiple fields side by side separate them with commas. For cpu usage and select query count.

ebergen@etna:(~/svn/emt/bin) ./emt_view -f cpu_usr,mysql_com.select

[------emt------] [-cpu-] [mysql-] 
Timestamp         Usr%    Com      
                          select   
 2009-04-03 16:12  1       94      
 2009-04-03 16:13  1       27      
 2009-04-03 16:14  1       46      
 2009-04-03 16:15  1       67      
 2009-04-03 16:16  1       18   

Some plugins come with views. Alternatly you can create views out of any exisitng fields. To show the list of available views run emt_view -v and to display one use emt_view -s view_name. For the mysql view:

ebergen@etna:(~/svn/emt/bin) ./emt_view -s mysql -n 5

[------emt------] [---------------------------------------------------mysql---------------------------------------------------] 
Timestamp         Bytes In  Bytes Out  Com      Com      Com      Com      Com      Open Tables  Opened_tables  Conn      Run       
                                       commit   delete   insert   select   update                                                   
 2009-04-03 16:12  56K       1M         3        1        6        94       22       1647         0              1         1        
 2009-04-03 16:13  16K       944K       2        0        0        27       10       1647         0              1         1        
 2009-04-03 16:14  39K       1M         3        0        0        46       10       1647         0              1         1        
 2009-04-03 16:15  32K       1M         2        0        2        67       14       1647         0              1         1        
 2009-04-03 16:16  9K        956K       2        0        0        18       3        1647         0              1         1    

Here is an example of comparing several different application and system stats with a single emt_view call

ebergen@etna:(~/svn/emt/doc/html) emt_view -f cpu_usr,cpu_sys,mysql_com.select,mysql_com.update,mysql_com.commit,apache_total_accesses,apache_total_bytes,send_bytes.eth0,recv_bytes.eth0 -n 5

[------emt------] [------apache-------] [-----cpu-----] [-------network-------] [---------mysql----------] 
Timestamp         Requests   Bytes      Usr%    Sys%    Recv Bytes  Send Bytes  Com      Com      Com      
                                                        eth0        eth0        commit   select   update   
 2009-04-03 16:14  40         24K        1       0       69K         219K        3        46       10      
 2009-04-03 16:15  35         94K        1       0       78K         327K        2        67       14      
 2009-04-03 16:16  26         22K        1       0       75K         166K        2        18       3       
 2009-04-03 16:17  16         3K         2       1       111K        282K        0        22       3       
 2009-04-03 16:18  51         86K        2       1       122K        430K        2        67       7