Report database physical IO activity per IO type and oracle files type in real time

Introduction

After I published the blog post related to the db_io_metrics utiliy (based on gv$filestat and gv$tempstat), Luca Canali suggested me to create a version based on the gv$iostat_file cumulative view (available since 11.1).

The advantages of this view are:

  • it displays information about disk I/O statistics on a lot of file types (including data files, temp files,control files, log files, archive logs, and so on).
  • it takes care of the IO type (small,large,reads, writes and synchronous).

Then based on this, I created a new utility: db_io_type_metrics

db_io_type_metrics description

The db_io_type_metrics.pl utility is used to display database physical IO type (small, large, synchronous, reads and writes) real-time metrics. It basically takes a snapshot each second (default interval) from the gv$iostat_file cumulative view and computes the delta with the previous snapshot. The utility is RAC and Multitenant aware.

This utility:

  • provides useful metrics.
  • is RAC aware.
  • detects if it is connected to a multitenant database and then is able to display the containers metrics.
  • is fully customizable: you can aggregate the results depending on your needs.
  • does not install anything into the database.

It displays the following metrics per IO Type (small, large, synchronous, reads and writes):

  • MB/s: Megabytes per second.
  • RQ/s: Requests per second.
  • Avg MB/RQ: Average Megabytes per request.
  • Avg ms/RQ: Average ms per request.

At the following levels:

  • Database Instance.
  • Database container.
  • File Type (log file, control file, data file, temp file…) or tablespace.

Let’s see the help:

./db_io_type_metrics.pl -help

Usage: ./db_io_type_metrics.pl [-interval] [-count] [-inst] [-cont] [-file_type_tbs] [-io_type] [-file_type] [-tbs] [-show] [-display] [-sort_field] [-help]

 Default Interval : 1 second.
 Default Count    : Unlimited

  Parameter         Comment                                                                     Default
  ---------         -------                                                                     -------
  -INST=            ALL - Show all Instance(s)                                                  ALL
                    CURRENT - Show Current Instance
  -CONT=            Container to collect (wildcard allowed)                                     ALL
  -FILE_TYPE_TBS=   Collect on File Type or on Tablespace: file_type,tbs                        FILE_TYPE
  -IO_TYPE=         IO Type to collect: reads,writes,small,large,synch                          READS
  -FILE_TYPE=       File Type to collect (in case FILE_TYPE_TBS=file_type) (wildcard allowed)   NONE
  -TBS=             Tablespace to collect (in case FILE_TYPE_TBS=tbs) (wildcard allowed)        NONE
  -SHOW=            What to show: inst,cont,file_type_tbs (comma separated list)                INST
  -DISPLAY=         What to display: snap,avg (comma separated list)                            SNAP
  -SORT_FIELD=      small_reads,small_writes,large_reads,large_writes                           NONE

Example: ./db_io_type_metrics.pl
Example: ./db_io_type_metrics.pl  -inst=CBDT1
Example: ./db_io_type_metrics.pl  -show=inst,file_type_tbs
Example: ./db_io_type_metrics.pl  -show=inst,file_type_tbs -file_type=%Data%
Example: ./db_io_type_metrics.pl  -show=inst -io_type=large
Example: ./db_io_type_metrics.pl  -show=inst -io_type=small -sort_field=small_reads
Example: ./db_io_type_metrics.pl  -show=inst,file_type_tbs -file_type_tbs=tbs -tbs=%USE%
Example: ./db_io_type_metrics.pl  -show=inst,cont
Example: ./db_io_type_metrics.pl  -show=inst,cont -cont=%P%
Example: ./db_io_type_metrics.pl  -show=inst,cont,file_type_tbs -io_type=small -sort_field=small_reads

The main options/features are:

  1. You can choose the number of snapshots to display and the time to wait between snapshots.
  2. You can choose on which database instance to collect the metrics thanks to the -INST= parameter.
  3. You can choose on which database container to collect the metrics thanks to the -CONT= parameter.
  4. You can choose to collect on File Type or tablespace thanks to the -FILE_TYPE_TBS=parameter.
  5. You can choose on which IO Type to collect the metrics thanks to the -IO_TYPE= parameter.
  6. You can choose on which File Type to collect the metric thanks to the -FILE_TYPE=parameter (wilcard allowed).
  7. You can choose on which Tablespace to collect the metric thanks to the -TBS=parameter (wilcard allowed).
  8. You can aggregate the results on the database instances, containers, file type or tablespace level thanks to the -SHOW= parameter.
  9. You can display the metrics per snapshot, the average metrics value since the collection began (that is to say since the script has been launched) or both thanks to the -DISPLAY= parameter.
  10. You can sort based on the number of small_reads, number of small_writes, number of large_reads or number of large_writes thanks to the -SORT_FIELD= parameter.

Let’s see some use cases:

Report the IO type metrics for “reads” IO per database instances, tablespaces for the SLOB tablespace:

 ./db_io_type_metrics.pl  -show=inst,file_type_tbs -file_type_tbs=tbs -tbs=%SLOB% -io_type=reads
............................
Collecting 1 sec....
............................

......... SNAP TAKEN AT ...................

10:52:54                                               SMALL R   SMALL R   LARGE R   LARGE R   Avg MB/   Avg MB/   Avg ms/   Avg ms/
10:52:54   INST         FILE_TYPE_TBS                  MB/s      RQ/s      MB/s      RQ/s      SMALL R   LARGE R   SMALL R   LARGE R
10:52:54   ----------   ----------------------------   -------   -------   -------   -------   -------   -------   -------   -------
10:52:54   BDT_1                                       144       18390     0         0         0.008     0.0       0.08      0.00
10:52:54   BDT_1        SLOB                           144       18390     0         0         0.008     0.0       0.08      0.00

 

Report the IO type metrics for “small” IO” and all file type:

./db_io_type_metrics.pl  -show=file_type_tbs -file_type_tbs=file_type -io_type=small
............................
Collecting 1 sec....
............................

......... SNAP TAKEN AT ...................

10:57:01                                               SMALL R   SMALL R   SMALL W   SMALL W   Avg MB/   Avg MB/   Avg ms/   Avg ms/
10:57:01   INST         FILE_TYPE_TBS                  MB/s      RQ/s      MB/s      RQ/s      SMALL R   SMALL W   SMALL R   SMALL W
10:57:01   ----------   ----------------------------   -------   -------   -------   -------   -------   -------   -------   -------
10:57:01                Archive Log                    0         0         0         0         0.000     0.000     0.00      0.00
10:57:01                Archive Log Backup             0         0         0         0         0.000     0.000     0.00      0.00
10:57:01                Control File                   1         66        0         0         0.015     0.000     0.00      0.00
10:57:01                Data File                      125       16230     0         0         0.008     0.000     0.15      0.00
10:57:01                Data File Backup               0         0         0         0         0.000     0.000     0.00      0.00
10:57:01                Data File Copy                 0         0         0         0         0.000     0.000     0.00      0.00
10:57:01                Data File Incremental Backup   0         0         0         0         0.000     0.000     0.00      0.00
10:57:01                Data Pump Dump File            0         0         0         0         0.000     0.000     0.00      0.00
10:57:01                Flashback Log                  0         0         0         0         0.000     0.000     0.00      0.00
10:57:01                Log File                       0         0         0         0         0.000     0.000     0.00      0.00
10:57:01                Other                          0         0         0         0         0.000     0.000     0.00      0.00
10:57:01                Temp File                      0         0         0         0         0.000     0.000     0.00      0.00

 

Report the IO type metrics for “small” IO per database instances and containers:

./db_io_type_metrics.pl -show=inst,cont -io_type=small
............................
Collecting 1 sec....
............................

......... SNAP TAKEN AT ...................

13:07:46                                                                 SMALL R   SMALL R   SMALL W   SMALL W   Avg MB/   Avg MB/   Avg ms/   Avg ms/
13:07:46   INST         CONT              FILE_TYPE_TBS                  MB/s      RQ/s      MB/s      RQ/s      SMALL R   SMALL W   SMALL R   SMALL W
13:07:46   ----------   ---------------   ----------------------------   -------   -------   -------   -------   -------   -------   -------   -------
13:07:46   CBDT1                                                         2         97        0         1         0.021     0.000     0.03      1.00
13:07:46   CBDT1        CDB$ROOT                                         2         97        0         1         0.021     0.000     0.03      1.00
13:07:46   CBDT1        PDB$SEED                                         0         0         0         0         0.000     0.000     0.00      0.00
13:07:46   CBDT1        P_1                                              0         0         0         0         0.000     0.000     0.00      0.00
13:07:46   CBDT1        P_2                                              0         0         0         0         0.000     0.000     0.00      0.00
13:07:46   CBDT1        P_3                                              0         0         0         0         0.000     0.000     0.00      0.00
13:07:46   CBDT2                                                         1         96        0         1         0.010     0.000     0.09      2.00
13:07:46   CBDT2        CDB$ROOT                                         1         96        0         1         0.010     0.000     0.09      2.00
13:07:46   CBDT2        PDB$SEED                                         0         0         0         0         0.000     0.000     0.00      0.00
13:07:46   CBDT2        P_1                                              0         0         0         0         0.000     0.000     0.00      0.00
13:07:46   CBDT2        P_2                                              0         0         0         0         0.000     0.000     0.00      0.00
13:07:46   CBDT2        P_3                                              0         0         0         0         0.000     0.000     0.00      0.00

 

Report the IO type metrics per… I let you finish the sentence as the utility is customizable enough ;-)

You can download it from this repository or copy the source code from this page.

Conclusion:

Three utilities are now available to report IO metrics in real time depending on our needs:

  1. asm_metrics for reads and writes metrics related to ASM.
  2. db_io_metrics for reads and writes metrics related to data files and temp files.
  3. db_io_type_metrics for reads, writes, small, large and synchronous metrics related to data files, temp files,control files, log files, archive logs, and so on.

Enjoy and don’t hesitate to come back to me in case of questions, issues or suggestions.

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2 Responses to Report database physical IO activity per IO type and oracle files type in real time

  1. Mohan says:

    The script is prompting for show_fields package – Where to get that pkg?

    • bdrouvot says:

      Hello Mohan,

      show_fields is part of the script, so most probably you got copy/paste issues with the source code.

      I suggest to download the script instead.

      Once downloaded you may get :

      ./db_io_type_metrics.pl
      : No such file or directory

      In that case, dos2unix the script or launch it invoking perl that way: perl ./db_io_type_metrics.pl

      Hope it helps,
      Bertrand

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