exadata_metrics.pl: New feature to collect real-time metrics extracted from cumulative metrics

I am a big fan of real-time metrics extraction based on the cumulative metrics: That is to say take a snapshot each second (default interval) from the cumulative metrics and computes the delta with the previous snapshot.

I build such tools for ASM metrics and for Exadata Cell metrics.

Recently, I added a new feature to the asm_metrics.pl script: The ability to display the average delta values since the collection began (Means since we launched the script).

Well, I just added this new feature to the exadata_metrics.pl script.

Of course the old features remain:

  • You can choose the number of snapshots to display and the time to wait between the snapshots.
  • You can choose to filter on name and objectname based on predicates (see the help).
  • You can work on all the cells or a subset thanks to the CELL or the GROUPFILE parameter.
  • You can decide the way to compute the metrics with no aggregation, aggregation on cell, objectname or both.

Let’s see the help:

 ./exadata_metrics.pl help

Usage: ./exadata_metrics.pl [Interval [Count]] [cell=|groupfile=] [display=] [show=] [top=] [name=] [name!=] [objectname=] [objectname!=]

 Default Interval : 1 second.
 Default Count : Unlimited

 Parameter                 Comment                                                      Default
 ---------                 -------                                                      -------
 CELL=                     comma-separated list of cells
 GROUPFILE=                file containing list of cells
 SHOW=                     What to show (name included): cell,objectname                ALL
 DISPLAY=                  What to display: snap,avg (comma separated list)             SNAP
 TOP=                      Number of rows to display                                    10
 NAME=                     ALL - Show all cumulative metrics (wildcard allowed)         ALL
 NAME!=                    Exclude cumulative metrics (wildcard allowed)                EMPTY
 OBJECTNAME=               ALL - Show all objects (wildcard allowed)                    ALL
 OBJECTNAME!=              Exclude objects (wildcard allowed)                           EMPTY

utility assumes passwordless SSH from this cell node to the other cell nodes
utility assumes ORACLE_HOME has been set (with celladmin user for example)

Example : ./exadata_metrics.pl cell=cell
Example : ./exadata_metrics.pl groupfile=./cell_group
Example : ./exadata_metrics.pl groupfile=./cell_group show=name
Example : ./exadata_metrics.pl cell=cell objectname='CD_disk03_cell' name!='.*RQ_W.*'
Example : ./exadata_metrics.pl cell=cell name='.*BY.*' objectname='.*disk.*' name!='GD.*' objectname!='.*disk1.*'

The “display” option is the new one: It allows you to display the delta snap values (as previously), the average delta values since the collection began (that is to say since the script has been launched) or both.

Let’s see one example:

I want to extract real-time metrics from the %IO_TM_R% cumulative ones, for 2 cells and aggregate the results for all the cells and all the objectname (means I just want to show the metrics). I want to see each snapshots and the average since we launched the script.

So, I launch the script that way:

./exadata_metrics.pl cell=exacell1,exacell2 display=avg,snap name='.*IO_TM_R.*' show=name

It will produce this kind of output:

--------------------------------------
----------COLLECTING DATA-------------
--------------------------------------

......... SNAP FOR LAST COLLECTION TIME ...................

DELTA(s)   CELL                    NAME                         OBJECTNAME                                                  VALUE
--------   ----                    ----                         ----------                                                  -----
60                                 CD_IO_TM_R_LG                                                                            0.00 us
60                                 CD_IO_TM_R_SM                                                                            807269.00 us

......... AVG SINCE FIRST COLLECTION TIME...................

DELTA(s)   CELL                    NAME                         OBJECTNAME                                                  VALUE
--------   ----                    ----                         ----------                                                  -----
60                                 CD_IO_TM_R_LG                                                                            0.00 us
60                                 CD_IO_TM_R_SM                                                                            807269.00 us

So, no differences between the delta snap and the average after the first snap (which is obvious 🙂 ).

Into the “SNAP” section, the delta(s) field computes the delta in seconds of the collectionTime recorded into the snapshots (see this post for more details). Into the “AVG” section, the delta(s) field is the sum of the delta(s) field from all the previous “SNAP” sections.

Let’s have a look to the output after 2 minutes of metrics extraction to make things clear:

--------------------------------------
----------COLLECTING DATA-------------
--------------------------------------

......... SNAP FOR LAST COLLECTION TIME ...................

DELTA(s)   CELL                    NAME                         OBJECTNAME                                                  VALUE
--------   ----                    ----                         ----------                                                  -----
61                                 CD_IO_TM_R_LG                                                                            0.00 us
61                                 CD_IO_TM_R_SM                                                                            348479.00 us

......... AVG SINCE FIRST COLLECTION TIME...................

DELTA(s)   CELL                    NAME                         OBJECTNAME                                                  VALUE
--------   ----                    ----                         ----------                                                  -----
121                                CD_IO_TM_R_LG                                                                            0.00 us
121                                CD_IO_TM_R_SM                                                                            577874.00 us

So, during the last 61 seconds of collection the CD_IO_TM_R_SM metric delta value is 348479.00 us.

It leads to an average of 577874.00 us since the collection began (That is to say since 121 seconds of metrics collection).

Remarks:

  • The exadata_metrics.pl script can be downloaded from this repository.
  • The DELTA (s) field is an important one to interpret the result correctly, I strongly recommend to read this post for a better understanding of it.

Conclusion:

The exadata_metrics.pl now offers the ability to display the average delta values since the collection began (that is to say since the script has been launched).

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