Oracle Database 12.2 New Features – SQL* Plus Enhancements

I want to start a series of posts about Oracle Database 12.2 new features this new year 2018.
There’s no better start of this series than to start with SQL*Plus.
SQL*Plus is probably one of the most utilized tools by DBA’s (sqlcl is gaining steam) and here I show some really cool new features.

SQL*Plus History

With this command HIST[ORY] and if turned on; you can run, edit, delete or list previously used SQL or PL/SQL commands for the current session.
  
 $ sqlplus sys as sysdba
SQL*Plus: Release 12.2.0.1.0 Production on Fri Jan 5 12:28:58 2018
Copyright (c) 1982, 2016, Oracle.  All rights reserved.
Enter password:
Connected to:
Oracle Database 12c Enterprise Edition Release 12.2.0.1.0 – 64bit Production
SQL> show history
history is OFF
SQL> set history on
SQL> show history
history is ON and set to “100”
SQL> set history 1000
SQL> show history
history is ON and set to “1000”
SQL> show user
USER is “SYS”
SQL> desc dual
 Name                                                      Null?    Type
 —————————————– ——– —————————-
 DUMMY                                                                 VARCHAR2(1)
SQL> select * from dual;
D
X
SQL> hist
  1  show history
  2  show user
  3  desc dual
  4  select * from dual;
SQL> hist 4 run
D
X
SQL>

SQL*Plus SET MARKUP CSV

This setting is going to present the output is CVS format. 
SQL> set markup csv on
SQL> select * from emp;
“EMPNO”,”ENAME”,”JOB”,”MGR”,”HIREDATE”,”SAL”,”COMM”,”DEPTNO”
7839,”KING”,”PRESIDENT”,,”17-NOV-81″,5000,,10
7698,”BLAKE”,”MANAGER”,7839,”01-MAY-81″,2850,,30
7782,”CLARK”,”MANAGER”,7839,”09-JUN-81″,2450,,10
7566,”JONES”,”MANAGER”,7839,”02-APR-81″,2975,,20
7788,”SCOTT”,”ANALYST”,7566,”19-APR-87″,3000,,20
7902,”FORD”,”ANALYST”,7566,”03-DEC-81″,3000,,20
7369,”SMITH”,”CLERK”,7902,”17-DEC-80″,800,,20
7499,”ALLEN”,”SALESMAN”,7698,”20-FEB-81″,1600,300,30
7521,”WARD”,”SALESMAN”,7698,”22-FEB-81″,1250,500,30
7654,”MARTIN”,”SALESMAN”,7698,”28-SEP-81″,1250,1400,30
7844,”TURNER”,”SALESMAN”,7698,”08-SEP-81″,1500,0,30
7876,”ADAMS”,”CLERK”,7788,”23-MAY-87″,1100,,20
7900,”JAMES”,”CLERK”,7698,”03-DEC-81″,950,,30
7934,”MILLER”,”CLERK”,7782,”23-JAN-82″,1300,,10
14 rows selected.

SQL*Plus SET FEEDBACK ONLY

This option will display the number of rows selected without displaying the data. Useful to measure fetch time.
SQL> set feedback only
SQL> set timing on
SQL> select * from emp;
14 rows selected.
Elapsed: 00:00:00.01

SQL*Plus Performance Settings


SET ROWPREFECTH (default 1 | 2G max)
This setting pre-fetches rows in a result set. It can reduce the number of round trips between OCI execute calls.
I had an interesting question from a colleague about this setting. What is the difference between this ROWPREFECTH and ARRAYSIZE?
I’m still struggling to find the differences. Here are both definitions extracted from Oracle’s documentation:
SET ARRAYSIZE
Sets the number of rows that SQL*Plus will fetch from the database at one time. Valid values are 1 to 5000.
The effectiveness of setting ARRAYSIZE depends on how well Oracle Database fills network packets and your network latency and throughput. In recent versions of SQL*Plus and Oracle Database, ARRAYSIZE may have little effect. Overlarge sizes can easily take more SQL*Plus memory which may decrease overall performance.

SET ROWPREFETCH {1 | n}

Sets the number of rows that SQL*Plus will prefetch from the database at one time.
The default value is 1.
What I can see from here is that ARRAYSIZE takes place during the fetch step and probably ROWPREFECTH is just before the fetch step?
I even tried to identify this by using the autotrace option and by tracing a test session, but unfortunately I was not able to find any differences. Maybe the amount of data queried wasn’t large enough.
$ sqlplus scott/****
SQL*Plus: Release 12.2.0.1.0 Production on Fri Jan 5 13:18:41 2018
Copyright (c) 1982, 2016, Oracle.  All rights reserved.
Last Successful login time: Fri Jan 05 2018 13:15:53 -05:00
Connected to:
Oracle Database 12c Enterprise Edition Release 12.2.0.1.0 – 64bit Production
SQL> set autotrace on
SQL> select * from emp;
14 rows selected.
Execution Plan
———————————————————-
Plan hash value: 3956160932
————————————————————————–
| Id  | Operation         | Name | Rows  | Bytes | Cost (%CPU)| Time    |
————————————————————————–
|   0 | SELECT STATEMENT  |         |    14 |  1218 |     3   (0)| 00:00:01 |
|   1 |  TABLE ACCESS FULL| EMP  |    14 |  1218 |     3   (0)| 00:00:01 |
————————————————————————–
Note
—–
   – dynamic statistics used: dynamic sampling (level=2)
Statistics
———————————————————-
            0  recursive calls
            0  db block gets
            8  consistent gets
            0  physical reads
            0  redo size
       1537  bytes sent via SQL*Net to client
          608  bytes received via SQL*Net from client
            2  SQL*Net roundtrips to/from client
            0  sorts (memory)
            0  sorts (disk)
           14  rows processed
SQL> set rowprefetch 10
SQL> select * from emp;
14 rows selected.
Execution Plan
———————————————————-
Plan hash value: 3956160932
————————————————————————–
| Id  | Operation         | Name | Rows  | Bytes | Cost (%CPU)| Time    |
————————————————————————–
|   0 | SELECT STATEMENT  |         |    14 |  1218 |     3   (0)| 00:00:01 |
|   1 |  TABLE ACCESS FULL| EMP  |    14 |  1218 |     3   (0)| 00:00:01 |
————————————————————————–
Note
—–
   – dynamic statistics used: dynamic sampling (level=2)
Statistics
———————————————————-
            0  recursive calls
            0  db block gets
            8  consistent gets
            0  physical reads
            0  redo size
       1534  bytes sent via SQL*Net to client
          608  bytes received via SQL*Net from client
            2  SQL*Net roundtrips to/from client
            0  sorts (memory)
            0  sorts (disk)
           14  rows processed
SQL> set rowprefetch 5
SQL> select * from emp;
14 rows selected.
Execution Plan
———————————————————-
Plan hash value: 3956160932
————————————————————————–
| Id  | Operation         | Name | Rows  | Bytes | Cost (%CPU)| Time    |
————————————————————————–
|   0 | SELECT STATEMENT  |         |    14 |  1218 |     3   (0)| 00:00:01 |
|   1 |  TABLE ACCESS FULL| EMP  |    14 |  1218 |     3   (0)| 00:00:01 |
————————————————————————–
Note
—–
   – dynamic statistics used: dynamic sampling (level=2)
Statistics
———————————————————-
            0  recursive calls
            0  db block gets
            8  consistent gets
            0  physical reads
            0  redo size
       1534  bytes sent via SQL*Net to client
          608  bytes received via SQL*Net from client
            2  SQL*Net roundtrips to/from client
            0  sorts (memory)
            0  sorts (disk)
           14  rows processed
SQL> set arraysize 5
SQL> select * from emp;
14 rows selected.
Execution Plan
———————————————————-
Plan hash value: 3956160932
————————————————————————–
| Id  | Operation         | Name | Rows  | Bytes | Cost (%CPU)| Time    |
————————————————————————–
|   0 | SELECT STATEMENT  |         |    14 |  1218 |     3   (0)| 00:00:01 |
|   1 |  TABLE ACCESS FULL| EMP  |    14 |  1218 |     3   (0)| 00:00:01 |
————————————————————————–
Note
—–
   – dynamic statistics used: dynamic sampling (level=2)
Statistics
———————————————————-
            0  recursive calls
            0  db block gets
            8  consistent gets
            0  physical reads
            0  redo size
       1534  bytes sent via SQL*Net to client
          608  bytes received via SQL*Net from client
            2  SQL*Net roundtrips to/from client
            0  sorts (memory)
            0  sorts (disk)
           14  rows processed
SQL> set rowprefetch 1
SQL> select * from emp;
14 rows selected.
Execution Plan
———————————————————-
Plan hash value: 3956160932
————————————————————————–
| Id  | Operation         | Name | Rows  | Bytes | Cost (%CPU)| Time    |
————————————————————————–
|   0 | SELECT STATEMENT  |         |    14 |  1218 |     3   (0)| 00:00:01 |
|   1 |  TABLE ACCESS FULL| EMP  |    14 |  1218 |     3   (0)| 00:00:01 |
————————————————————————–
Note
—–
   – dynamic statistics used: dynamic sampling (level=2)
Statistics
———————————————————-
            0  recursive calls
            0  db block gets
           10  consistent gets
            0  physical reads
            0  redo size
       1919  bytes sent via SQL*Net to client
          630  bytes received via SQL*Net from client
            4  SQL*Net roundtrips to/from client
            0  sorts (memory)
            0  sorts (disk)
           14  rows processed
As you can see the only visible changes are the SQL*Net roundtrips to/from client of the ARRAYSIZE setting.
SET LOBPREFETCH (default 0 bytes | 2G max)
Similar to ROWPREFECTH but for LOB data.

SET STATEMENTCACHE (default 0 | 32767 max)
This setting will cache similar SQL statements for the current session reducing the amount of necessary parses.
Thanks,

Alfredo

Free Database Seminar in Timisoara, Romania

Today I want to talk about a free Database Seminar that ACI is sponsoring in Timisoara, Romania. A friend of mine and former co-worker asked me to speak in the seminar about Oracle Enterprise Manager Administration. 

Because of the Time zone’s differences, I’m going to make a recording of the presentation and upload it to the blog, so he can show it there.

If you are nearby Timisoara, don’t loose the opportunity to assist and learn little bit more about databases.

The event is going to take place April, 8th at 5 pm @ City Business Centre, building D, Timisoara, RO.

Did I forget to mention that the event is for free?

For more information go to:






Thanks,

Alfredo

Oracle Enterprise Manager – Reducing the noise, Part 1

Enterprise Manager 12c is a great monitoring tool, with it you can monitor a wide range of target types from databases to middleware; although out-of-the-box metrics can suit your monitoring requirements they can generate a considerable amount of white noise. In order to reduce this noise first you have to identify which are the top alerts in your system; Cloud Control comes with several predefined reports that help you to dig into multiple areas of your system, there’s a report “20 Most Common Alerts” which shows you the incidence of common alerts.


In the picture above, you can clearly see that metric “Database Time Spent Waiting (%)” appears twice in my Top 3, let’s find out our metric setting for my DB targets; in order to do this we must go to a DB home page then Oracle Database -> Monitoring -> Metrics and Collection Settings.  

 
Wait a minute! Why I’m receiving alerts if there are no thresholds setup for any of those metrics?, this behavior is clearly explained in MOS note 1500074.1 about a default warning threshold of 30% inside the database configuration. Let’s take a look to dba_threshold to confirm.
set lines 300
column METRICS_NAME format a30
column WARNING_OPERATOR format a30
column WARNING_VALUE format a30
column CRITICAL_OPERATOR format a30
column CRITICAL_VALUE format a30
SELECT METRICS_NAME,WARNING_OPERATOR ,WARNING_VALUE,CRITICAL_OPERATOR ,CRITICAL_VALUE FROM DBA_THRESHOLDS;
METRICS_NAME                        WARNING_OPERATOR               WARNING_VALUE                  CRITICAL_OPERATOR              CRITICAL_VALUE
———————————– —————————— —————————— —————————— ——————————
Average Users Waiting Counts        GT                             10                             NONE
Average Users Waiting Counts        GT                             10                             NONE
Average Users Waiting Counts        GT                             10                             NONE
Average Users Waiting Counts        GT                             10                             NONE
Average Users Waiting Counts        GT                             10                             NONE
Average Users Waiting Counts        GT                             10                             NONE
Average Users Waiting Counts        GT                             30                             NONE
Average Users Waiting Counts        GT                             30                             NONE
Blocked User Session Count          GT                             0                              NONE
Current Open Cursors Count          GT                             1200                           NONE
Database Time Spent Waiting (%)     GT                             30                             NONE
Database Time Spent Waiting (%)     GT                             30                             NONE
Database Time Spent Waiting (%)     GT                             30                             NONE
Database Time Spent Waiting (%)     GT                             30                             NONE
Database Time Spent Waiting (%)     GT                             30                             NONE
Database Time Spent Waiting (%)     GT                             30                             NONE
Database Time Spent Waiting (%)     GT                             50                             NONE
Database Time Spent Waiting (%)     GT                             50                             NONE
Logons Per Sec                      GE                             100                            NONE
Session Limit %                     GT                             90                             GT                             97
Tablespace Bytes Space Usage        DO NOT CHECK                   0                              DO_NOT_CHECK                   0
Tablespace Space Usage              GE                             85                             GE                             97
22 rows selected.
There you go!, all metrics for “Database Time Spent Waiting (%)” are set to 30% or 50% values, now the trick to disable these metrics is to set them to a different value like 99%; this will override the default value as follows:

  
Let’s look at the database setting again:
set lines 300
column METRICS_NAME format a30
column WARNING_OPERATOR format a30
column WARNING_VALUE format a30
column CRITICAL_OPERATOR format a30
column CRITICAL_VALUE format a30
METRICS_NAME                        WARNING_OPERATOR               WARNING_VALUE                  CRITICAL_OPERATOR              CRITICAL_VALUE
———————————– —————————— —————————— —————————— ——————————
Average Users Waiting Counts        GT                             10                             NONE
Average Users Waiting Counts        GT                             10                             NONE
Average Users Waiting Counts        GT                             10                             NONE
Average Users Waiting Counts        GT                             10                             NONE
Average Users Waiting Counts        GT                             10                             NONE
Average Users Waiting Counts        GT                             10                             NONE
Average Users Waiting Counts        GT                             30                             NONE
Average Users Waiting Counts        GT                             30                             NONE
Blocked User Session Count          GT                             0                              NONE
Current Open Cursors Count          GT                             1200                           NONE
Database Time Spent Waiting (%)     GT                             99                             NONE
Database Time Spent Waiting (%)     GT                             99                             NONE
Database Time Spent Waiting (%)     GT                             99                             NONE
Database Time Spent Waiting (%)     GT                             99                             NONE
Database Time Spent Waiting (%)     GT                             99                             NONE
Database Time Spent Waiting (%)     GT                             99                             NONE
Database Time Spent Waiting (%)     GT                             99                             NONE
Database Time Spent Waiting (%)     GT                             99                             NONE
Database Time Spent Waiting (%)     GT                             99                             NONE
Database Time Spent Waiting (%)     GT                             99                             NONE
Database Time Spent Waiting (%)     GT                             99                             NONE
Logons Per Sec                      GE                             100                            NONE
Session Limit %                     GT                             90                             GT                             97
Tablespace Bytes Space Usage        DO NOT CHECK                   0                              DO_NOT_CHECK                   0
Tablespace Space Usage              GE                             85                             GE                             97
25 rows selected.
We successfully modified these metrics to a very high value; at this point you can decide to stay at 99% or you can remove that threshold in order to completely disable them.

Now let’s confirm those settings in the database:
set lines 300
column METRICS_NAME format a30
column WARNING_OPERATOR format a30
column WARNING_VALUE format a30
column CRITICAL_OPERATOR format a30
column CRITICAL_VALUE format a30
METRICS_NAME                        WARNING_OPERATOR               WARNING_VALUE                  CRITICAL_OPERATOR              CRITICAL_VALUE
———————————– —————————— —————————— —————————— ——————————
Average Users Waiting Counts        GT                             10                             NONE
Average Users Waiting Counts        GT                             10                             NONE
Average Users Waiting Counts        GT                             10                             NONE
Average Users Waiting Counts        GT                             10                             NONE
Average Users Waiting Counts        GT                             10                             NONE
Average Users Waiting Counts        GT                             10                             NONE
Average Users Waiting Counts        GT                             30                             NONE
Average Users Waiting Counts        GT                             30                             NONE
Blocked User Session Count          GT                             0                              NONE
Current Open Cursors Count          GT                             1200                           NONE
Logons Per Sec                      GE                             100                            NONE
Session Limit %                     GT                             90                             GT                             97
Tablespace Bytes Space Usage        DO NOT CHECK                   0                              DO_NOT_CHECK                   0
Tablespace Space Usage              GE                             85                             GE                             97
14 rows selected.
The metrics are not there anymore and hopefully the alerts neither. This behavior is also noted for “Average Users Waiting Counts” metric, if you are receiving considerable white noise for this metric you can disable as well following the same procedure. A good practice is to create a Monitoring template to help you modify these thresholds for multiple targets at once.
Stay tuned for my next post about reducing OEM 12c noise.
Thanks,

Alfredo

Extract AWR data to build Response Time graphs (awrrtsys.sql)

This SQL script extract AWR data required to perform Response Time analysis for Oracle Databases. All information about it will be presented in the IOUG Collaborate 2014 session “553: Oracle Database Performance: Are Database Users Telling Me The Truth?”
–#********************************************************************
–#– Filename           : awrrtsys.sql
–#– Author             : Alfredo Krieg
–#– Original           : 17-Oct-12
–#– Last Update        : 21-Ago-13
–#– Description        : awrrtsys.sql- System Response time per snapshot in the last x days
–#                        per desired unit of work –
–#– Usage              : start awrrtsys.sql
–#– This script use AWR data (licensing is required)
–#********************************************************************
set termout on
set feedback off
set heading on
set linesize 150
set pagesize 100
set feedback off verify off
col snap_id           format  999999     heading “Snapshot Id”
col instance_number   format  99         heading “Instance Number”
col snap_time         format  a25        heading “Snap Begin Time”
col non_idle_wait     format  9999999.99 heading “Qt (s)”
col cpu_time          format  9999999.99 heading “St (s)”
col lio               format  9999999.99 heading “LIO”
col pio               format  9999999.99 heading “PIO”
col uw_variable       format  9999999.99 heading “UC”
col rt_ms_per_lio     format  9999999.99 heading “RT (ms/lio)”
col rt_ms_per_pio     format  9999999.99 heading “RT (ms/pio)”
col rt_ms_per_uw      format  9999999.99 heading “RT (ms/uc)”
SELECT a.SNAP_ID,
         b.instance_number,
         TO_CHAR (END_INTERVAL_TIME, ‘mon/dd/yyyy HH24:mi’) AS snap_time,
         non_idle_wait,
         background_cpu+
         db_cpu as cpu_time,
         lio,
         pio,
         uwvariable AS UW_VARIABLE,
         ROUND (
            ( ( (background_cpu + db_cpu) / lio) + (non_idle_wait / lio))
            * 1000,
            4)
            AS RT_ms_per_lio,
         ROUND (
            ( ( (background_cpu + db_cpu) / pio) + (non_idle_wait / pio))
            * 1000,
            4)
            AS RT_ms_per_pio,
         ROUND (
            ( ( (background_cpu + db_cpu) / (uwvariable))
             + (non_idle_wait / (uwvariable)))
            * 1000,
            4)
            AS RT_ms_per_uw
    FROM ( 
    SELECT SNAP_ID,
                   SUM (non_idle_wait) AS non_idle_wait,
                   ROUND (SUM (background_cpu), 0) AS background_cpu,
                   ROUND (SUM (db_cpu), 0) AS db_cpu,
                   SUM (lio) AS lio,
                   SUM (pio) AS pio,
                   SUM (uwvariable) AS uwvariable
              FROM (
              SELECT SNAP_ID,
                           ROUND (time_secs, 0) non_idle_wait,
                           0 AS background_cpu,
                           0 AS db_cpu,
                           0 AS lio,
                           0 AS pio,
                           0 AS uwvariable
                      FROM (  SELECT snap_id,
                                     ‘WAIT’ AS wait_class,
                                     ‘Non Idle’ AS name,
                                     (SUM (VALUE) – SUM (value1)) / 1000000
                                        AS time_secs
                                FROM (  SELECT snap_id,
                                               0 AS snap2,
                                               SUM (time_waited_micro) AS VALUE,
                                               0 AS value1
                                          FROM dba_hist_system_event
                                         WHERE wait_class ‘Idle’
                                      GROUP BY snap_id
                                      UNION
                                        SELECT snap_id + 1,
                                               snap_id,
                                               0,
                                               SUM (time_waited_micro) AS value1
                                          FROM dba_hist_system_event
                                         WHERE wait_class ‘Idle’
                                      GROUP BY snap_id)
                            GROUP BY snap_id)
                    UNION
                      SELECT snap_id,
                             0,
                             (SUM (VALUE) – SUM (value1)) / 1000000
                                AS background_cpu,
                             0,
                             0,
                             0,
                             0                       
                        FROM (SELECT snap_id,
                                     0 AS snap2,
                                     stat_name,
                                     VALUE,
                                     0 AS value1
                                FROM dba_hist_sys_time_model
                               WHERE stat_name IN (‘background cpu time’)
                              UNION
                              SELECT snap_id + 1,
                                     snap_id,
                                     stat_name,
                                     0,
                                     VALUE AS value1
                                FROM dba_hist_sys_time_model
                               WHERE stat_name IN (‘background cpu time’))
                    GROUP BY snap_id, stat_name
                    UNION
                      SELECT snap_id,
                             0,
                             0,
                             (SUM (VALUE) – SUM (value1)) / 1000000 AS db_cpu,
                             0,
                             0,
                             0                          
                        FROM (SELECT snap_id,
                                     0 AS snap2,
                                     stat_name,
                                     VALUE,
                                     0 AS value1
                                FROM dba_hist_sys_time_model
                               WHERE stat_name IN (‘DB CPU’)
                              UNION
                              SELECT snap_id + 1,
                                     snap_id,
                                     stat_name,
                                     0,
                                     VALUE AS value1
                                FROM dba_hist_sys_time_model
                               WHERE stat_name IN (‘DB CPU’))
                    GROUP BY snap_id, stat_name
                    UNION
                      SELECT snap_id,
                             0,
                             0,
                             0,
                             SUM (VALUE) – SUM (value1) AS lio,
                             0,
                             0                           
                        FROM (SELECT snap_id,
                                     0 AS snap2,
                                     stat_name,
                                     VALUE,
                                     0 AS value1
                                FROM DBA_HIST_SYSSTAT
                               WHERE stat_name IN (‘session logical reads’)
                              UNION
                              SELECT snap_id + 1,
                                     snap_id,
                                     stat_name,
                                     0,
                                     VALUE AS value1
                                FROM DBA_HIST_SYSSTAT
                               WHERE stat_name IN (‘session logical reads’))
                    GROUP BY snap_id, stat_name
                    UNION
                      SELECT snap_id,
                             0,
                             0,
                             0,
                             0,
                             SUM (VALUE) – SUM (value1) AS pio,
                             0                           
                        FROM (SELECT snap_id,
                                     0 AS snap2,
                                     stat_name,
                                     VALUE,
                                     0 AS value1
                                FROM DBA_HIST_SYSSTAT
                               WHERE stat_name IN (‘physical reads’)
                              UNION
                              SELECT snap_id + 1,
                                     snap_id,
                                     stat_name,
                                     0,
                                     VALUE AS value1
                                FROM DBA_HIST_SYSSTAT
                               WHERE stat_name IN (‘physical reads’))
                    GROUP BY snap_id, stat_name
                    UNION
                      SELECT snap_id,
                             0,
                             0,
                             0,
                             0,
                             0,
                             SUM (VALUE) – SUM (value1) AS uwvariable                          
                        FROM (SELECT snap_id,
                                     0 AS snap2,
                                     stat_name,
                                     VALUE,
                                     0 AS value1
                                FROM DBA_HIST_SYSSTAT
                               WHERE stat_name IN (‘&1’)
                              UNION
                              SELECT snap_id + 1,
                                     snap_id,
                                     stat_name,
                                     0,
                                     VALUE AS value1
                                FROM DBA_HIST_SYSSTAT
                               WHERE stat_name IN (‘&1’))
                    GROUP BY snap_id, stat_name
                    )
          GROUP BY snap_id
            HAVING SUM (background_cpu) >= 0
          ORDER BY snap_id DESC) a, DBA_HIST_SNAPSHOT B
   WHERE a.SNAP_ID = b.SNAP_ID AND BEGIN_INTERVAL_TIME > SYSDATE – &2

ORDER BY 1;

Oracle 12c ASM new features


Today I will talk about some new features for ASM on 12c version.
Oracle Flex ASM
Oracle Flex ASM is a set of new features that provide critical capabilities required for cloud computing. Oracle Flex ASM redefines the traditional ASM cluster architecture of having one ASM instance on every node in the cluster; this means you can have less ASM instances than nodes in your cluster. In this configuration the number of ASM instances running is called ASM cardinality, by default the ASM cardinality is 3 and can be changed with a Clusterware command.
What are the benefits?
On the traditional architecture when an ASM instance fails; all DB instances connected to that instance in the node will also fail. With Oracle Flex ASM if the ASM instance fail the Clusterware will relocate that ASM instance to a different node and the DB instances will remotely (through private network) connect to the relocated ASM instance, all without disruption to the DB client.
Dedicated ASM Network
This new 12c feature provides the option to dedicate a private network for ASM network traffic only. There’s also the option to use the Oracle Clusterware interconnect private network.
Remote Access
As per the new Oracle Flex ASM feature, the DB instance can remotely connect to ASM instance hence the need of a password file in order to authenticate remote DB instances to ASM. Oracle Flex ASM has the ability of storing password files in a Disk Group and is extended to DB clients; this is really useful to avoid synchronizing multiple password files within the cluster.
Oracle Flex ASM is one of the most important enhancements to ASM in 12c version, however in the below whitepaper describes the rest of new features present.
Bertrand Drouvot has already tested this Oracle Flex ASM feature and uploaded the contents into his own blog (http://bdrouvot.wordpress.com/2013/06/29/build-your-own-flex-asm-12c-lab-using-virtual-box/).
Another interesting feature is the Extent Reading Selection Enhancement which evenly distributes the selection of which copy of a block is read in ASM Disk Groups with normal or high redundancy. This feature is enabled by default in 12c and states that users on I/O bound systems should notice a performance improvement while reading blocks from disks.
Thanks,
Alfredo

Why my new Disk Group is not getting mounted automatically when ASM instance starts?

Today I faced the issue that a new ASM Disk Group created in instance +ASM1 is not getting automatically mounted in instance +ASM2.

The first step was to check DB dependencies:

[oracle@ol5-112-rac2 trace]$ srvctl config database -d RAC
Database unique name: RAC
Database name: RAC
Oracle home: /u01/app/oracle/product/11.2.0/db_1
Oracle user: oracle
Spfile: +DATA/RAC/spfileRAC.ora
Domain: localdomain
Start options: open
Stop options: immediate
Database role: PRIMARY
Management policy: AUTOMATIC
Server pools: RAC
Database instances: RAC1,RAC2
Disk Groups: DATA
Services: reports
Database is administrator managed
You can see that only dependent Disk Groups are ‘DATA’.

Let us add ‘FRA’ also as dependent Disk Group:

[oracle@ol5-112-rac2 trace]$ srvctl modify database -d RAC -a ‘DATA,FRA’
[oracle@ol5-112-rac2 trace]$ srvctl config database -d RAC
Database unique name: RAC
Database name: RAC
Oracle home: /u01/app/oracle/product/11.2.0/db_1
Oracle user: oracle
Spfile: +DATA/RAC/spfileRAC.ora
Domain: localdomain
Start options: open
Stop options: immediate
Database role: PRIMARY
Management policy: AUTOMATIC
Server pools: RAC
Database instances: RAC1,RAC2
Disk Groups: DATA,FRA
Services: reports
Database is administrator managed
The next step is to add the Disk Groups to ASM_DISKGROUPS parameter:

SQL> ALTER SYSTEM SET ASM_DISKGROUPS=’DATA’,’FRA’ scope=both sid=’+ASM1′;
System altered.
SQL> ALTER SYSTEM SET ASM_DISKGROUPS=’DATA’,’FRA’ scope=both sid=’+ASM2′;
System altered.
After restarting +ASM2 instance we can see that FRA Disk Group is mounted automatically:

[oracle@ol5-112-rac2 trace]$ sqlplus / as sysasm
SQL*Plus: Release 11.2.0.1.0 Production on Wed Jun 12 15:44:44 2013
Copyright (c) 1982, 2009, Oracle.  All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 – Production
With the Real Application Clusters and Automatic Storage Management options
SQL> set lines 1000
SQL> select * from V$ASM_DISKGROUP;
GROUP_NUMBER NAME                           SECTOR_SIZE BLOCK_SIZE ALLOCATION_UNIT_SIZE STATE       TYPE     TOTAL_MB    FREE_MB HOT_USED_MB COLD_USED_MB REQUIRED_MIRROR_FREE_MB USABLE_FILE_MB OFFLINE_DISKS COMPATIBILITY                                                DATABASE_COMPATIBILITY                                       V
———— —————————— ———– ———- ——————– ———– —— ———- ———- ———– ———— ———————– ————– ————- ———————————————————— ———————————————————— –
           1 DATA                                   512       4096              1048576 MOUNTED     EXTERN      15342      12616           0         2726                       0          12616     0 11.2.0.0.0                                                   10.1.0.0.0                                                   N
           2 FRA                                    512       4096              1048576 MOUNTED     EXTERN       6133       5962           0          171                       0           5962     0 11.2.0.0.0                                                   10.1.0.0.0                                                   N
SQL> exit
Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 – Production
With the Real Application Clusters and Automatic Storage Management options
Thanks,

Alfredo

ORA-15097: cannot SHUTDOWN ASM instance with connected client

In 11g R2 Clusterware configurations the OCR is located in ASM disk, that’s why ASM can’t be shutdown while the cluster is running.  You have to shutdown your cluster in order to shutdown ASM instance.

Oracle support note 984663.1

Here’s a good blog about this:
Example, how to shutdown ASM instance on node ol5-112-rac1:
[oracle@ol5-112-rac1 ~]$ crsctl status resource -t
——————————————————————————–
NAME           TARGET  STATE        SERVER                   STATE_DETAILS
——————————————————————————–
Local Resources
——————————————————————————–
ora.DATA.dg
               ONLINE  ONLINE       ol5-112-rac1
               ONLINE  ONLINE       ol5-112-rac2
ora.FRA.dg
               OFFLINE OFFLINE      ol5-112-rac1
               ONLINE  ONLINE       ol5-112-rac2
ora.LISTENER.lsnr
               ONLINE  ONLINE       ol5-112-rac1
               ONLINE  ONLINE       ol5-112-rac2
ora.asm
               ONLINE  ONLINE       ol5-112-rac1
               ONLINE  ONLINE       ol5-112-rac2             Started
ora.eons
               ONLINE  ONLINE       ol5-112-rac1
               ONLINE  ONLINE       ol5-112-rac2
ora.gsd
               OFFLINE OFFLINE      ol5-112-rac1
               OFFLINE OFFLINE      ol5-112-rac2
ora.net1.network
               ONLINE  ONLINE       ol5-112-rac1
               ONLINE  ONLINE       ol5-112-rac2
ora.ons
               ONLINE  ONLINE       ol5-112-rac1
               ONLINE  ONLINE       ol5-112-rac2
——————————————————————————–
Cluster Resources
——————————————————————————–
ora.LISTENER_SCAN1.lsnr
      1        ONLINE  ONLINE       ol5-112-rac1
ora.oc4j
      1        OFFLINE OFFLINE
ora.ol5-112-rac1.vip
      1        ONLINE  ONLINE       ol5-112-rac1
ora.ol5-112-rac2.vip
      1        ONLINE  ONLINE       ol5-112-rac2
ora.rac.db
      1        ONLINE  ONLINE       ol5-112-rac2             Open
      2        ONLINE  ONLINE       ol5-112-rac1
ora.rac.reports.svc
      1        ONLINE  ONLINE       ol5-112-rac1
ora.scan1.vip
      1        ONLINE  ONLINE       ol5-112-rac1
[oracle@ol5-112-rac1 ~]$
Shutdown RAC1 instance first:

[oracle@ol5-112-rac1 ~]$ srvctl stop instance –d RAC –I RAC1 –o immediate
Then proceed to shutdown cluster (root required):

[oracle@ol5-112-rac1 ~]$ su –
[root@ol5-112-rac1 bin]#
[root@ol5-112-rac1 bin]# ./crsctl stop cluster
CRS-2673: Attempting to stop ‘ora.crsd’ on ‘ol5-112-rac1’
CRS-2790: Starting shutdown of Cluster Ready Services-managed resources on ‘ol5-112-rac1’
CRS-2673: Attempting to stop ‘ora.LISTENER.lsnr’ on ‘ol5-112-rac1’
CRS-2673: Attempting to stop ‘ora.DATA.dg’ on ‘ol5-112-rac1’
CRS-2677: Stop of ‘ora.LISTENER.lsnr’ on ‘ol5-112-rac1’ succeeded
CRS-2673: Attempting to stop ‘ora.ol5-112-rac1.vip’ on ‘ol5-112-rac1’
CRS-2677: Stop of ‘ora.ol5-112-rac1.vip’ on ‘ol5-112-rac1’ succeeded
CRS-2672: Attempting to start ‘ora.ol5-112-rac1.vip’ on ‘ol5-112-rac2’
CRS-2676: Start of ‘ora.ol5-112-rac1.vip’ on ‘ol5-112-rac2’ succeeded
CRS-2677: Stop of ‘ora.DATA.dg’ on ‘ol5-112-rac1’ succeeded
CRS-2673: Attempting to stop ‘ora.asm’ on ‘ol5-112-rac1’
CRS-2677: Stop of ‘ora.asm’ on ‘ol5-112-rac1’ succeeded
CRS-2673: Attempting to stop ‘ora.ons’ on ‘ol5-112-rac1’
CRS-2673: Attempting to stop ‘ora.eons’ on ‘ol5-112-rac1’
CRS-2677: Stop of ‘ora.ons’ on ‘ol5-112-rac1’ succeeded
CRS-2673: Attempting to stop ‘ora.net1.network’ on ‘ol5-112-rac1’
CRS-2677: Stop of ‘ora.net1.network’ on ‘ol5-112-rac1’ succeeded
CRS-2677: Stop of ‘ora.eons’ on ‘ol5-112-rac1’ succeeded
CRS-2792: Shutdown of Cluster Ready Services-managed resources on ‘ol5-112-rac1’ has completed
CRS-2677: Stop of ‘ora.crsd’ on ‘ol5-112-rac1’ succeeded
CRS-2673: Attempting to stop ‘ora.cssdmonitor’ on ‘ol5-112-rac1’
CRS-2673: Attempting to stop ‘ora.ctssd’ on ‘ol5-112-rac1’
CRS-2673: Attempting to stop ‘ora.evmd’ on ‘ol5-112-rac1’
CRS-2673: Attempting to stop ‘ora.asm’ on ‘ol5-112-rac1’
CRS-2677: Stop of ‘ora.cssdmonitor’ on ‘ol5-112-rac1’ succeeded
CRS-2677: Stop of ‘ora.evmd’ on ‘ol5-112-rac1’ succeeded
CRS-2677: Stop of ‘ora.ctssd’ on ‘ol5-112-rac1’ succeeded
CRS-2677: Stop of ‘ora.asm’ on ‘ol5-112-rac1’ succeeded
CRS-2673: Attempting to stop ‘ora.cssd’ on ‘ol5-112-rac1’
CRS-2677: Stop of ‘ora.cssd’ on ‘ol5-112-rac1’ succeeded
CRS-2673: Attempting to stop ‘ora.diskmon’ on ‘ol5-112-rac1’
CRS-2677: Stop of ‘ora.diskmon’ on ‘ol5-112-rac1’ succeeded
[root@ol5-112-rac1 bin]# ps -ef|grep pmon
root      7072  5722  0 14:45 pts/2    00:00:00 grep pmon
[root@ol5-112-rac1 bin]# ps -ef|grep +ASM1
root      7074  5722  0 14:46 pts/2    00:00:00 grep +ASM1
[root@ol5-112-rac1 bin]#
At this point ASM & Cluster Ready Services managed resources are down.

In order to start them again just need to issue:

[root@ol5-112-rac1 bin]# ./crsctl start cluster
[root@ol5-112-rac1 bin]# exit
[oracle@ol5-112-rac1 ~]$ srvctl start instance –d RAC –I RAC1

Thanks,
Alfredo