Oracle Multitenant – Part 1 – What is multitenant?

The Oracle database multitenant architecture was introduced in version 12c release 1. This architecture consists of a container database (CDB) that contains one or more pluggable databases (PDB). The CDB acts as a metadata repository for the PDBs and a source of user accounts that are utilized across the PDBs called common users. The CDB and PDB share resources, but not data. A PDB template or “seed” database allows the quick deployment of PDBs out of the CDB. This architecture was created with consolidation in mind and according to the Oracle 12c release 1 documentation, will become the default database architecture as the non-CDB architecture is deprecated (https://docs.oracle.com/database/121/UPGRD/deprecated.htm#BABDBCJI).

My current work has been in non-CDB environments, but given that non-CDB databases are being deprecated, it is in my interest to start working with CDB databases. I plan to share this work with you in a series of posts for (hopefully) mutual benefit.

The multitenant architecture is a separately licensed option from Oracle, but there is an exception. If the CDB contains a single PDB, then no additional licensing is required.   This way, you can start converting non-CDB databases to CDB without having to accrue additional licensing cost.

The PDBs can be ‘plugged’ and ‘unplugged’ between container databases within limits. Access to the PDBs within a CDB is handled via SQL*Net. Whenever a PDB is created, a service of the same name is also created to handle the PDB connections and the service is automatically registered with the database listener.   It is recommended to change the name of this service for security reasons.

While the CDB and PDB share resources such as memory and processes, each has their own SYS and SYSAUX tablespace with associated objects.   There is one common UNDO tablespace at the CDB level (one per instance for RAC) to be shared, but each PDB has its own TEMP tablespace.

There is a laundry list of features in the Oracle Documentation that this new architecture provides involving consolidation:

  • Cost reduction: By consolidating hardware and sharing database memory and files, you reduce costs for hardware, storage, availability, and labor. For example, 100 PDBs on a single server share one database instance and one set of database files, thereby requiring less hardware and fewer personnel.
  • Easier and more rapid movement of data and code: By design, you can quickly plug a PDB into a CDB, unplug the PDB from the CDB, and then plug this PDB into a different CDB. The implementation technique for plugging and unplugging is similar to the transportable tablespace technique.
  • Easier management and monitoring of the physical database: The CDB administrator can attend to one physical database (one set of files and one set of database instances) rather than split attention among dozens or hundreds of non-CDBs. Backup strategies and disaster recovery are simplified.
  • Separation of data and code: Although consolidated into a single physical database, PDBs mimic the behavior of non-CDBs. For example, if user error loses critical data, a PDB administrator can use Oracle Flashback or point-in-time recovery to retrieve the lost data without affecting other PDBs.
  • Secure separation of administrative duties: A user account is common, which means that it can connect to any container on which it has privileges, or local, which means that it is restricted to a specific PDB. A CDB administrator can use a common user account to manage the CDB. A PDB administrator uses a local account to manage an individual PDB. Because a privilege is contained within the container in which it is granted, a local user on one PDB does not have privileges on other PDBs within the same CDB.
  • Ease of performance tuning: It is easier to collect performance metrics for a single database than for multiple databases. It is easier to size one SGA than 100 SGAs.
  • Support for Oracle Database Resource Manager: In a multitenant environment, one concern is contention for system resources among the PDBs running on the same computer. Another concern is limiting resource usage for more consistent, predictable performance. To address such resource contention, usage, and monitoring issues, you can use Oracle Database Resource Manager.
  • Fewer database patches and upgrades: It is easier to apply a patch to one database than to 100 databases, and to upgrade one database than to upgrade 100 databases.

The previous benefits were from the first release of CDB in Oracle version 12c release 1. Oracle 12c release 2 added the following features, although this is not a complete list:

  • CDBs can now support “thousands” of PDBs instead of the previous maximum of 252.
  • A PDB can now have a different character set than the CDB
  • Point-in-time copies of PDBs possible for development and testing purposes
  • PDB flashback now possible by setting up restore points
  • PDBs can have their own UNDO tablespaces
  • Upgrade a CDB with one or more PDBs in a single operation

 

Next up in this series – Creating, connecting to, removing, and querying CDBs and PDBs

 

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Creating Corruption for Recovery Practice

Backup and recovery should be the first item on any DBA’s list when administering a new environment.  Often the emphasis is placed on backups and that is only half of creating a successful backup and recovery solution for a production environment.  Making sure recovery is possible from a situation such as block corruption using the backups is the other and arguably the more important half.

As newer versions of Oracle more availability features and higher reliability, block corruption rarely happens. New recovery features, like table recovery in version 12c are also introduced over time.  This is a good thing, but the problem is practicing recovery methods when recovery is not necessary.  The only option most DBA’s have is recovering production database backups into a non-production  environment.  While this may be enough of a backup validation process for most, it leaves the question of knowing how to handle a situation where less than a full recovery of production data is necessary.  Documenting proven recovery steps for full as well as partial recoveries will help during times of crisis when tension is high.

Using a virtual environment, I will demonstrate how to manually corrupt a database so that recovery becomes necessary.  The actual steps to recover the database once it is damaged will not be covered in this post as it has already been documented extensively in both the Oracle documentation and other DBA posts.

My virtual environment will consist of a single-instance non-ASM non-container database version 12.1.0.2.0 on a Oracle Enterprise Linux 7u3 platform.  I will mention additional steps to perform this process on an ASM or Windows-hosted environment as well.  In this Linux environment, we will use the utility dd to perform the actual corruption.

After ensuring my database was in archivelog mode, I created my test objects:

SQL> create tablespace jontest_tsp datafile '/u01/app/oracle/oradata/JON12C/datafile/jontest_tsp1.dbf'
size 100M autoextend on next 1M extent management local segment space management auto;
  2  
Tablespace created.

SQL> create user jontest identified by semperf1 default tablespace jontest_tsp;

User created.

SQL> grant connect, resource to jontest;

Grant succeeded.

SQL> alter user jontest quota unlimited on jontest_tsp;

User altered.

SQL> conn jontest/semperf1
Connected.


SQL> create table table_dbc as select dbms_random.value(0,100) N1 from dual connect by level <= 1000;

Table created.

 

SQL> column segment_name format a10;

SQL> select segment_name, tablespace_name from user_segments where 
segment_name='TABLE_DBC';
  2  
SEGMENT_NA TABLESPACE_NAME
---------- ------------------------------
TABLE_DBC  JONTEST_TSP

Now that we have our test objects in place, it is time to get a backup of our environment.

RMAN> backup database plus archivelog delete input;

Starting backup at 07-JUN-17
current log archived
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=17 device type=DISK
channel ORA_DISK_1: starting archived log backup set
channel ORA_DISK_1: specifying archived log(s) in backup set
input archived log thread=1 sequence=4 RECID=1 STAMP=946036509
input archived log thread=1 sequence=5 RECID=2 STAMP=946040464
channel ORA_DISK_1: starting piece 1 at 07-JUN-17
channel ORA_DISK_1: finished piece 1 at 07-JUN-17
piece handle=/u01/app/oracle/fast_recovery_area/JON12C/backupset/2017_06_07/o1_mf_annnn_FULL_20170607_dmjhv16k_.bkp tag=FULL_20170607 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
channel ORA_DISK_1: deleting archived log(s)
archived log file name=/u01/app/oracle/fast_recovery_area/JON12C/archivelog/2017_06_07/o1_mf_1_4_dmjczcsb_.arc RECID=1 STAMP=946036509
archived log file name=/u01/app/oracle/fast_recovery_area/JON12C/archivelog/2017_06_07/o1_mf_1_5_dmjhv02b_.arc RECID=2 STAMP=946040464
Finished backup at 07-JUN-17

Starting backup at 07-JUN-17
using channel ORA_DISK_1
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00001 name=/u01/app/oracle/oradata/JON12C/datafile/o1_mf_system_dmj83mqt_.dbf
input datafile file number=00003 name=/u01/app/oracle/oradata/JON12C/datafile/o1_mf_sysaux_dmj82jkj_.dbf
input datafile file number=00005 name=/u01/app/oracle/oradata/JON12C/datafile/jontest_tsp1.dbf
input datafile file number=00004 name=/u01/app/oracle/oradata/JON12C/datafile/o1_mf_undotbs1_dmj851z7_.dbf
input datafile file number=00006 name=/u01/app/oracle/oradata/JON12C/datafile/o1_mf_users_dmj850wr_.dbf
channel ORA_DISK_1: starting piece 1 at 07-JUN-17
channel ORA_DISK_1: finished piece 1 at 07-JUN-17
piece handle=/u01/app/oracle/fast_recovery_area/JON12C/backupset/2017_06_07/o1_mf_nnndf_TAG20170607T130106_dmjhv391_.bkp tag=TAG20170607T130106 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:01:25
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
including current control file in backup set
including current SPFILE in backup set
channel ORA_DISK_1: starting piece 1 at 07-JUN-17
channel ORA_DISK_1: finished piece 1 at 07-JUN-17
piece handle=/u01/app/oracle/fast_recovery_area/JON12C/backupset/2017_06_07/o1_mf_ncsnf_TAG20170607T130106_dmjhxrz3_.bkp tag=TAG20170607T130106 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:02
Finished backup at 07-JUN-17

Starting backup at 07-JUN-17
current log archived
using channel ORA_DISK_1
channel ORA_DISK_1: starting archived log backup set
channel ORA_DISK_1: specifying archived log(s) in backup set
input archived log thread=1 sequence=6 RECID=3 STAMP=946040554
channel ORA_DISK_1: starting piece 1 at 07-JUN-17
channel ORA_DISK_1: finished piece 1 at 07-JUN-17
piece handle=/u01/app/oracle/fast_recovery_area/JON12C/backupset/2017_06_07/o1_mf_annnn_FULL_20170607_dmjhxt9k_.bkp tag=FULL_20170607 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
channel ORA_DISK_1: deleting archived log(s)
archived log file name=/u01/app/oracle/fast_recovery_area/JON12C/archivelog/2017_06_07/o1_mf_1_6_dmjhxt47_.arc RECID=3 STAMP=946040554
Finished backup at 07-JUN-17

RMAN>

If your particular environment is using ASM for datafile storage instead of the filesystem like my environment, follow these steps to copy the datafile to the OS where you can apply the corruption process.  Make note of the backup tag identifier.

alter database datafile '+DATA/RAC/DATAFILE/jontest_tsp1.df' offline;

rman target=/

RMAN> BACKUP AS COPY DATAFILE '+DATA/RAC/DATAFILE/jontest_tsp1.df' FORMAT '/tmp/jontest_tsp_%f';

After the datafile is out of ASM or the datafile is in a filesystem, check the header block as a SYSDBA user:

SQL> select header_file, header_block from dba_segments where segment_name='TABLE_DBC';

HEADER_FILE HEADER_BLOCK
----------- ------------
   5      130

The header of segment (table) is block 130, so if we damage the next block with dd, we will cause a datafile/table corruption.

[oracle@localhost ~]$ dd of=/u01/app/oracle/oradata/JON12C/datafile/jontest_tsp1.dbf bs=8192 conv=notrunc seek=131 <<EOF
> #corrupt_this#
> EOF
0+1 records in
0+1 records out
15 bytes (15 B) copied, 8.3023e-05 s, 181 kB/s

Execute DBVERIFY to confirm that we have generated some corruption:

[oracle@localhost ~]$ dbv file=/u01/app/oracle/oradata/JON12C/datafile/jontest_tsp1.dbf blocksize=8192

DBVERIFY: Release 12.1.0.2.0 - Production on Wed Jun 7 14:08:25 2017

Copyright (c) 1982, 2014, Oracle and/or its affiliates.  All rights reserved.

DBVERIFY - Verification starting : FILE = /u01/app/oracle/oradata/JON12C/datafile/jontest_tsp1.dbf
Page 131 is marked corrupt
Corrupt block relative dba: 0x01400083 (file 5, block 131)
Bad header found during dbv: 
Data in bad block:
 type: 35 format: 3 rdba: 0x74707572
 last change scn: 0x2373.6968745f seq: 0xa flg: 0x04
 spare1: 0x6f spare2: 0x72 spare3: 0x0
 consistency value in tail: 0x8ca90602
 check value in block header: 0xb1ea
 computed block checksum: 0x176

As an interesting side note, even though DBVERIFY noticed the corruption, if we queried v$database_block_corruption, we would not see any entries:

SQL> select * from v$database_block_corruption;

no rows selected

If we immediately query the affected table, the database will see the corruption:

SQL> select count(*)
  2  from table_dbc;
select count(*)
       *
ERROR at line 1:
ORA-01578: ORACLE data block corrupted (file # 5, block # 131)
ORA-01110: data file 5: '/u01/app/oracle/oradata/JON12C/datafile/jontest_tsp1.dbf'

The v$database_block_corruption view now has the appropriate entries

SQL> select * from v$database_block_corruption;

     FILE#     BLOCK#   BLOCKS CORRUPTION_CHANGE# CORRUPTIO   CON_ID
---------- ---------- ---------- ------------------ --------- ----------
  5   131        1    0 CORRUPT        0

RMAN will also populate this view if it encounters corrupt blocks.  This is why it is a good practice to either review RMAN backup logfiles or query the v$database_block_corruption view at the end of a backup.

If this was an ASM datafile, restore it to the original location:

rman target /

RUN
{
SET MAXCORRUPT FOR DATAFILE '+DATA/RAC/DATAFILE/jontest_tsp1.df' TO 3;
RESTORE DATAFILE '+DATA/RAC/DATAFILE/jontest_tsp1.df' FROM TAG
'TAG20120303T111330';
RECOVER DATAFILE '+DATA/RAC/DATAFILE/jontest_tsp1.df';
}

After restore and recover the datafile must be brought online

alter database datafile '+DATA/RAC/DATAFILE/jontest_tsp1.df' online;

Now you can practice a datafile, table, or block recovery.

If we wanted to corrupt a datafile in a Windows environment, we could use an editor such as UltraEdit GUI editor, which is also available in a Linux version.  Using this editor, we can either modify the header of the file to corrupt the datafile, or scroll to the table data to corrupt just the table to practice table or block recovery.

I know this goes without saying, but just like the warning labels on hair dryers that tell you not to use them in the bathtub, YOU SHOULD NOT PERFORM THIS PROCESS AGAINST A PRODUCTION DATABASE, EVEN IF YOU CREATE A SEPARATE TABLESPACE THAT CONTAINS NO PRODUCTION DATA.  You know the reason for most warning labels is that someone probably did the very thing the label warns against doing.

 

ORA-16957: SQL Analyze time limit interrupt

time_expired

First thing this morning, I was greeted with an email from my alert log monitor containing the error in the title.  This is one of the less cryptic error messages from an Oracle database, but what does it mean?

If you are an Oracle DBA and have been dealing with performance issues for any length of time, you are familiar with the SQL Tuning Advisor.  This tool is part of the Oracle Tuning Pack .  It takes one or more SQL statements as input, analyzes them, and displays recommendations to tune the statements with rationale and expected benefits.  These recommendations can include collecting object statistics, creating indexes, creating SQL profiles or SQL plan baselines, and even recommendations to rewrite.

The SQL Tuning Advisor has two modes – automatic and manual.  The automatic mode is referred to as the Automatic SQL Tuning Task or SQL Analyze for short.  This task when enabled runs nightly as part of the default maintenance plan.  Usually it runs happily in the background and goes mostly unnoticed.  Other times it generates an ORA-16957 error. This error means that it has not completed within its limit settings. You can view these settings like this:

COLUMN parameter_value FORMAT A30  

SELECT parameter_name, parameter_value  
FROM dba_advisor_parameters  
WHERE task_name = 'SYS_AUTO_SQL_TUNING_TASK'  
AND parameter_name IN ('TIME_LIMIT','DEFAULT_EXECUTION_TYPE',
'SQL_LIMIT','LOCAL_TIME_LIMIT');

PARAMETER_NAME                 PARAMETER_VALUE  

------------------------------ ------------------------------  

LOCAL_TIME_LIMIT               1200  
TIME_LIMIT                     7200  
DEFAULT_EXECUTION_TYPE         TUNE SQL
SQL_LIMIT                      -1

The time_limit value is the total time in seconds that the SQL Analyze job is allowed per execution within the maintenance window.  The local_time_limit is the value in seconds that the SQL Analyze job is allowed to spend analyzing each individual SQL statement.  The sql_limit parameter is the number of SQL statements to examine per execution of the job.  The -1 number indicates no limit to the number of SQL statements the job can review within its time limit.

How does it determine which statements need to be analyzed?  From the Oracle documentation, the following quote is taken:

The automated SQL tuning task does not process the following types of SQL:

  • Ad hoc SQL statements or SQL statements that do not repeat within a week
  • Parallel queries
  • Queries that take too long to run after being SQL profiled, so that it is not practical for SQL Tuning Advisor to test execution
  • Recursive SQL

 You can run SQL Tuning Advisor on demand to tune the preceding types of SQL statements.

 

Can we find out what SQL statement caused the ORA-16957 error?

Get the execution_name for the long run day:

set lines 200 pages 100 
col error_message for a60 
col execution_name for a15 

select execution_name, advisor_name,to_char(execution_start,'dd-mon-yy hh:mi:ss'), to_char(execution_end,'dd-mon-yy hh:mi:ss'), status,error_message 
from dba_advisor_executions 
where task_name = 'SYS_AUTO_SQL_TUNING_TASK' 
order by execution_start desc;

Take the name of the execution you are interested in and place it into the query below to identify the ID of the SQL causing the overrun.  If a sufficient amount of time has passed, you may not get any data from this query.

SELECT sql_id, sql_text FROM dba_hist_sqltext 
WHERE sql_id IN (SELECT attr1 FROM dba_advisor_objects 
WHERE execution_name = '&execution_name' 
AND task_name = 'SYS_AUTO_SQL_TUNING_TASK' 
AND type = 'SQL' AND bitand(attr7,64) <> 0 );


 Then you can take the SQL_ID from the query above and run it through the manual mode of the SQL Tuning Advisor:

Create the tuning task:

DECLARE 
l_sql_tune_task_id VARCHAR2(100); 
BEGIN 
l_sql_tune_task_id := DBMS_SQLTUNE.create_tuning_task ( 
sql_id => '&SQL_ID', 
scope => DBMS_SQLTUNE.scope_comprehensive, 
time_limit => 99999,   --I use a large time out value 
task_name => 'my_tuning_task', 
description => 'Tuning task for statement blahblah.'); 
DBMS_OUTPUT.put_line('l_sql_tune_task_id: ' || l_sql_tune_task_id); 
END; 
/

 

Execute the tuning task:

BEGIN 
DBMS_SQLTUNE.EXECUTE_TUNING_TASK( task_name => 'my_tuning_task'); 
end; 
/

When the task is complete, get the report:

SET LONG 5000 
SET LONGCHUNKSIZE 5000 
SET LINESIZE 200 
SELECT DBMS_SQLTUNE.REPORT_TUNING_TASK('my_tuning_task') from DUAL;

Be sure to drop the tuning task before executing another.  NOTE – If the tuning task results recommend using a SQL Profile, then you MUST accept the profile before dropping the tuning task.  Otherwise, the recommended profile will be lost and you will need to run the tuning task again.

BEGIN
  dbms_sqltune.drop_tuning_task (task_name => 'my_tuning_task');
END;
/

 

In the event that the ORA-16957 error is seen on a regular basis, you may need to adjust the SQL Analyze task limits or limit the number of SQL statements analyzed. Use the DBMS_SQL_AUTOTUNE.SET_TUNING_TASK_PARAMETER procedure to change these values.  Here is an example of changing the time limit to 7200 seconds (2 hours):

BEGIN 
DBMS_SQLTUNE.SET_TUNING_TASK_PARAMETER(task_name => 'SYS_AUTO_SQL_TUNING_TASK', 
parameter => 'TIME_LIMIT', value => 7200); 
END; 
/

 

If you need to determine if the SQL Analyze job is running against your database, use this query:

SELECT CLIENT_NAME, STATUS
 FROM   DBA_AUTOTASK_CLIENT
 WHERE  CLIENT_NAME = 'sql tuning advisor';
  
 CLIENT_NAME          STATUS
 -------------------- --------
 sql tuning advisor   ENABLED

 

You can disable or enable the SQL Analyze job with these commands:

BEGIN
   DBMS_AUTO_TASK_ADMIN.ENABLE (
     client_name => 'sql tuning advisor'
 ,   operation   => NULL
 ,   window_name => NULL
 );
 END;
 /


 BEGIN
   DBMS_AUTO_TASK_ADMIN.DISABLE (
     client_name => 'sql tuning advisor'
 ,   operation   => NULL
 ,   window_name => NULL
 );
 END;
 /

If you are interested in viewing the latest SQL Analyze report:

VARIABLE l_report CLOB;

BEGIN
:l_report := DBMS_SQLTUNE.report_auto_tuning_task(
begin_exec => NULL,
end_exec => NULL,
type => DBMS_SQLTUNE.type_text,
level => DBMS_SQLTUNE.level_typical,
section => DBMS_SQLTUNE.section_all,
object_id => NULL,
result_limit => NULL
);
END;
/

SET LONG 1000000
PRINT :l_report

If this task is enabled in your database, then take advantage of its analysis.  Regular viewing of its output may help identify ‘usual suspects’ that continue to run poorly.

 

Blast from the past – Rollback segments

Those of us that have worked with Oracle databases over the years have seen new features come along that relieved some of the more challenging aspects of database administration (i.e. things that drove us crazy).  One of the new features we were happy to see was automatic undo management in Oracle 9i release 1.  This new feature made the challenge of managing rollback segments obsolete. In the days before automatic undo management, the DBA not only had to create the rollback tablespace, but also size and manage the rollback segments it contained.

For newer DBA’s, these terms may not be familiar, so a little background may be in order.  Before the undo tablespace, there was the rollback tablespace.  This was where Oracle maintained changed, but uncommitted data for read consistency, much like the undo tablespace.  The rollback tablespace was comprised of rollback segments which needed to be manually created by the DBA.  The number and size of these segments was at the discretion of the DBA.  If the number or size of the rollback segments was insufficient for the amount of database activity, then contention for the rollback segment data blocks was a real, and common, occurrence.

Here is a typical database creation script from the Oracle 8i release 3 (8.1.7) documentation:

CREATE DATABASE rbdb1
    CONTROLFILE REUSE
    LOGFILE '/u01/oracle/rbdb1/redo01.log' SIZE 1M REUSE,
            '/u01/oracle/rbdb1/redo02.log' SIZE 1M REUSE,
            '/u01/oracle/rbdb1/redo03.log' SIZE 1M REUSE,
            '/u01/oracle/rbdb1/redo04.log' SIZE 1M REUSE
    DATAFILE '/u01/oracle/rbdb1/system01.dbf' SIZE 10M REUSE 
      AUTOEXTEND ON
      NEXT 10M MAXSIZE 200M 
    CHARACTER SET WE8ISO8859P1;

CREATE ROLLBACK SEGMENT rb_temp STORAGE (INITIAL 100 k NEXT 250 k);

-- Alter temporary system tablespace online before proceding
ALTER ROLLBACK SEGMENT rb_temp ONLINE;

-- Create additional tablespaces ...
-- RBS: For rollback segments
-- USERs: Create user sets this as the default tablespace
-- TEMP: Create user sets this as the temporary tablespace
CREATE TABLESPACE rbs
    DATAFILE '/u01/oracle/rbdb1/rbs01.dbf' SIZE 5M REUSE AUTOEXTEND ON
      NEXT 5M MAXSIZE 150M;
CREATE TABLESPACE users
    DATAFILE '/u01/oracle/rbdb1/users01.dbf' SIZE 3M REUSE AUTOEXTEND ON
      NEXT 5M MAXSIZE 150M;
CREATE TABLESPACE temp
    DATAFILE '/u01/oracle/rbdb1/temp01.dbf' SIZE 2M REUSE AUTOEXTEND ON
      NEXT 5M MAXSIZE 150M;

-- Create rollback segments.  
CREATE ROLLBACK SEGMENT rb1 STORAGE(INITIAL 50K NEXT 250K)
  tablespace rbs;
CREATE ROLLBACK SEGMENT rb2 STORAGE(INITIAL 50K NEXT 250K)
  tablespace rbs;
CREATE ROLLBACK SEGMENT rb3 STORAGE(INITIAL 50K NEXT 250K)
  tablespace rbs;
CREATE ROLLBACK SEGMENT rb4 STORAGE(INITIAL 50K NEXT 250K)
  tablespace rbs;

-- Bring new rollback segments online and drop the temporary system one
ALTER ROLLBACK SEGMENT rb1 ONLINE;
ALTER ROLLBACK SEGMENT rb2 ONLINE;
ALTER ROLLBACK SEGMENT rb3 ONLINE;
ALTER ROLLBACK SEGMENT rb4 ONLINE;

ALTER ROLLBACK SEGMENT rb_temp OFFLINE;
DROP ROLLBACK SEGMENT rb_temp ;

As you can see, you had to create and online one system rollback segment in the system tablespace before you could create the other tablespaces including rollback with its inclusive rollback segments.  You then had to bring the rollback segments you created online.  The temporary rollback segment was taken offline and removed at the end for housekeeping.

Rollback segments still exist in the newer versions of the Oracle database, but they are automatically created and managed by internal processes.  Additional segments are automatically created as needed.

Here is the output from a 9i release 1 database.  The sys-owned rollback segment takes the place of the rb_temp rollback segment in the 8i database creation script present during the creation of the database.  The difference here is that it is created automatically as part of the database creation process.  The remaining rollback segments were created automatically when the undo tablespace was created.

SQL> select * from v$version;

BANNER
----------------------------------------------------------------
Oracle9i Enterprise Edition Release 9.0.1.1.1 - Production
PL/SQL Release 9.0.1.1.1 - Production
CORE    9.0.1.1.1       Production
TNS for 32-bit Windows: Version 9.0.1.1.0 - Production
NLSRTL Version 9.0.1.1.1 - Production


SQL> select segment_name, owner from dba_rollback_segs;

SEGMENT_NAME                   OWNER
------------------------------ ------
SYSTEM                         SYS
_SYSSMU1$                      PUBLIC
_SYSSMU2$                      PUBLIC
_SYSSMU3$                      PUBLIC
_SYSSMU4$                      PUBLIC
_SYSSMU5$                      PUBLIC
_SYSSMU6$                      PUBLIC
_SYSSMU7$                      PUBLIC
_SYSSMU8$                      PUBLIC
_SYSSMU9$                      PUBLIC
_SYSSMU10$                     PUBLIC


Except for the segment naming convention, things look very similar in a version 11.2.0.4.0 database

SQL> select * from v$version;

BANNER
--------------------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
PL/SQL Release 11.2.0.4.0 - Production
CORE    11.2.0.4.0      Production
TNS for Linux: Version 11.2.0.4.0 - Production
NLSRTL Version 11.2.0.4.0 - Production

SQL> select segment_name, owner from dba_rollback_segs;

SEGMENT_NAME                   OWNER
------------------------------ ------
SYSTEM                         SYS
_SYSSMU10_1197734989$          PUBLIC
_SYSSMU9_1650507775$           PUBLIC
_SYSSMU8_517538920$            PUBLIC
_SYSSMU7_2070203016$           PUBLIC
_SYSSMU6_1263032392$           PUBLIC
_SYSSMU5_898567397$            PUBLIC
_SYSSMU4_1254879796$           PUBLIC
_SYSSMU3_1723003836$           PUBLIC
_SYSSMU2_2996391332$           PUBLIC
_SYSSMU1_3724004606$           PUBLIC

When automatic undo management was first introduced, you could choose between MANUAL or AUTO.  The manual setting was the default and I suspect this had to do with not wanting to force this new feature on anyone.  It wasn’t until 11g release 1 that the AUTO setting became the default for this parameter.  These days, I don’t know of anyone who still uses manual redo management, although it is still available as of 12c release 2.   Although there are occasional ORA-01555 (snapshot too old) errors encountered with the use of auto undo management, this is one feature that I think was worth the wait.

 

 

SQL Server Health Check v2

The new version of my SQL Server health check script adds the following improvements:

–Added queries for database start time and up time
–Added query to display memory usage of in-memory OLTP tables

----------------------------------------------------------Start of script
--sql_server_health_check_v2.sql
--v2
--This is a non-intrusive script written to give an overall informational view of a 
--SQL Server 2005-2016(CTP3) server instance for the purpose of first-time review.
--
--Version 2 additions
--Added queries for start time and up time
--Added query to display memory usage of in-memory OLTP tables


use master
GO

--Node name

SELECT SERVERPROPERTY('ComputerNamePhysicalNetBIOS') AS [CurrentNodeName];

--Version

select @@version as [VERSION];


--Instance parameters

print N'Instance Parameter';


SELECT  *
FROM    sys.configurations
ORDER BY name ;


--Database listing

print N'Database list with Status and Recovery Model';

--Database startup time

print N'Start time';

SELECT DATEADD(ms,-sample_ms,GETDATE() )AS StartTime
FROM sys.dm_io_virtual_file_stats(1,1);


--Database uptime

print N'Up time';


DECLARE @server_start_time DATETIME,
@seconds_diff INT,
@years_online INT,
@days_online INT,
@hours_online INT,
@minutes_online INT,
@seconds_online INT ;

SELECT @server_start_time = login_time
FROM master.sys.sysprocesses
WHERE spid = 1 ;

SELECT @seconds_diff = DATEDIFF(SECOND, @server_start_time, GETDATE()),
@years_online = @seconds_diff / 31536000,
@seconds_diff = @seconds_diff % 31536000,
@days_online = @seconds_diff / 86400,
@seconds_diff = @seconds_diff % 86400,
@hours_online = @seconds_diff / 3600,
@seconds_diff = @seconds_diff % 3600,
@minutes_online = @seconds_diff / 60,
@seconds_online = @seconds_diff % 60 ;

SELECT @server_start_time AS server_start_time,
@years_online AS years_online,
@days_online AS days_online,
@hours_online AS hours_online,
@minutes_online AS minutes_online,
@seconds_online AS seconds_online ;


SELECT substring(name,1,40) AS name,  substring(state_desc,1,20) AS STATE, 
substring(recovery_model_desc,1,20) AS RECOVERY_MODEL
   FROM sys.databases
order by name;



--Database file size and growth settings

print N'Size and Growth';


select substring(b.name,1,40) AS DB_Name, substring(a.name,1,40) AS Logical_name, 
substring(a.filename,1,100) AS File_Name,
cast((a.size * 8.00) / 1024 as numeric(12,2)) as DB_Size_in_MB,
case when a.growth > 100 then 'In MB' else 'In Percentage' end File_Growth,
cast(case when a.growth > 100 then (a.growth * 8.00) / 1024
else (((a.size * a.growth) / 100) * 8.00) / 1024
end as numeric(12,2)) File_Growth_Size_in_MB,
case when ( maxsize = -1 or maxsize=268435456 ) then 'AutoGrowth Not Restricted' else 'AutoGrowth Restricted' end AutoGrowth_Status
from sysaltfiles a
join sysdatabases b on a.dbid = b.dbid
where DATABASEPROPERTYEX(b.name, 'status') = 'ONLINE'
order by b.name;


--Is this a Cluster Node?

SELECT 'Clustered', case when SERVERPROPERTY('IsClustered') = 0 then 'No'
else 'Yes' end;

--Nodes in Cluster

print N'Cluster Nodes';

SELECT * FROM fn_virtualservernodes();


--Is AlwaysOn enabled (2012 and above)?

SELECT 'AlwaysOn', case when SERVERPROPERTY('IsHadrEnabled') = 0 then 'No'
                        when SERVERPROPERTY('IsHadrEnabled') = 1 then 'Yes'
                        else SERVERPROPERTY('IsHadrEnabled') end;


--AlwaysOn status

declare @c int;
declare @rd nvarchar(60); 
declare @osd nvarchar(60);
declare @rhd nvarchar(60); 
declare @shd nvarchar(60); 
declare @csd nvarchar(60);
select @c = COUNT(name) 
from sys.all_objects
where name = 'dm_hadr_availability_replica_states';
if @c = 0
print N'No AlwaysOn Status';
else
select @rd = role_desc, @osd= case when operational_state_desc is null then 'Replica is not local'
                  else operational_state_desc end,
       @rhd = recovery_health_desc, @shd = synchronization_health_desc,
       @csd = connected_state_desc
from sys.dm_hadr_availability_replica_states;
print @rd
print @osd
print @rhd
print @shd
print @csd
  
	

--Memory usage per database

print N'Memory Usage per User Database';


SELECT 
                substring(DB_NAME(database_id),1,40) AS [Database Name]
                ,COUNT(*) * 8/1024.0 AS [Cached Size (MB)]
FROM 
                sys.dm_os_buffer_descriptors
WHERE 
                database_id > 4 
                AND database_id <> 32767
                AND db_name(database_id) <> 'SSISDB'
GROUP BY DB_NAME(database_id)
ORDER BY [Cached Size (MB)] DESC OPTION (RECOMPILE);



--Memory usage of in-memory OLTP tables

print N'In-memory OLTP table usage';
				      SELECT object_name(object_id) AS Name, *  
				      FROM sys.dm_db_xtp_table_memory_stats;


--Last backup time per database

SELECT substring(sdb.Name,1,40) AS DatabaseName,
COALESCE(CONVERT(VARCHAR(12), MAX(bus.backup_finish_date), 101),'-') AS LastBackUpTime
FROM sys.sysdatabases sdb
LEFT OUTER JOIN msdb.dbo.backupset bus ON bus.database_name = sdb.name
where sdb.Name <> 'tempdb'
GROUP BY sdb.Name;


--No log backups for FULL or BULK_LOGGED recovery model databases in last 30 days


print N'Databases with FULL or BULK_LOGGED recovery model and no log backups in last 30 days';


SELECT name AS at_risk_database
   FROM sys.databases
where recovery_model_desc in('FULL','BULK_LOGGED')
and name not in(
SELECT 
msdb.dbo.backupset.database_name AS DBName 
FROM msdb.dbo.backupmediafamily 
INNER JOIN msdb.dbo.backupset ON msdb.dbo.backupmediafamily.media_set_id = msdb.dbo.backupset.media_set_id 
WHERE (CONVERT(datetime, msdb.dbo.backupset.backup_start_date, 102) >= GETDATE() - 30)
and msdb..backupset.type = 'L'
group by msdb.dbo.backupset.database_name
);



--Databases with no backups at all in the last 30 says

print N'Databases with NO backups in last 30 days';

SELECT name AS at_risk_database
   FROM sys.databases
where name <> 'tempdb'
and name not in(
SELECT 
substring(msdb.dbo.backupset.database_name,1,40) AS DBName 
FROM msdb.dbo.backupmediafamily 
INNER JOIN msdb.dbo.backupset ON msdb.dbo.backupmediafamily.media_set_id = msdb.dbo.backupset.media_set_id 
WHERE (CONVERT(datetime, msdb.dbo.backupset.backup_start_date, 102) >= GETDATE() - 30)
group by msdb.dbo.backupset.database_name
);


--Backups for the previous week per database

print N'All backups for previous week';

SELECT 
CONVERT(CHAR(40), SERVERPROPERTY('Servername')) AS Server, 
substring(msdb.dbo.backupset.database_name,1,40) AS DBName, 
msdb.dbo.backupset.backup_start_date, 
msdb.dbo.backupset.backup_finish_date, 
msdb.dbo.backupset.expiration_date, 
CASE msdb..backupset.type 
WHEN 'D' THEN 'Database' 
WHEN 'L' THEN 'Log'
WHEN 'F' THEN 'File'
WHEN 'P' THEN 'Partial'
WHEN 'I' THEN 'Differential database'
WHEN 'G' THEN 'Differential file'
WHEN 'Q' THEN 'Differential partial'
WHEN NULL THEN msdb..backupset.type 
END AS backup_type, 
msdb.dbo.backupset.backup_size, 
substring(msdb.dbo.backupmediafamily.logical_device_name,1,50) AS logical_device_name, 
substring(msdb.dbo.backupmediafamily.physical_device_name,1,50) AS physical_device_name, 
substring(msdb.dbo.backupset.name,1,50) AS backupset_name, 
substring(msdb.dbo.backupset.description,1,50) AS description 
FROM msdb.dbo.backupmediafamily 
INNER JOIN msdb.dbo.backupset ON msdb.dbo.backupmediafamily.media_set_id = msdb.dbo.backupset.media_set_id 
WHERE (CONVERT(datetime, msdb.dbo.backupset.backup_start_date, 102) >= GETDATE() - 7) 
ORDER BY 
msdb.dbo.backupset.database_name, 
msdb.dbo.backupset.backup_finish_date;


--Jobs that failed in the last 24 hours

print N'Jobs Failing in last 24 hours';

-- Variable Declarations
DECLARE @PreviousDate datetime
DECLARE @Year VARCHAR(4)
DECLARE @Month VARCHAR(2)
DECLARE @MonthPre VARCHAR(2)
DECLARE @Day VARCHAR(2)
DECLARE @DayPre VARCHAR(2)
DECLARE @FinalDate INT
-- Initialize Variables
SET @PreviousDate = DATEADD(dd, -1, GETDATE()) -- Last 1 day
SET @Year = DATEPART(yyyy, @PreviousDate)
SELECT @MonthPre = CONVERT(VARCHAR(2), DATEPART(mm, @PreviousDate))
SELECT @Month = RIGHT(CONVERT(VARCHAR, (@MonthPre + 1000000000)),2)
SELECT @DayPre = CONVERT(VARCHAR(2), DATEPART(dd, @PreviousDate))
SELECT @Day = RIGHT(CONVERT(VARCHAR, (@DayPre + 1000000000)),2)
SET @FinalDate = CAST(@Year + @Month + @Day AS INT)
-- Final Logic
SELECT substring(j.[name],1,40) AS JOB,
substring(s.step_name,1,40) AS Step,
h.step_id,
substring(h.step_name,1,40) AS Step,
h.run_date,
h.run_time,
h.sql_severity,
substring(h.message,1,100) AS Message,
h.server
FROM msdb.dbo.sysjobhistory h
INNER JOIN msdb.dbo.sysjobs j
ON h.job_id = j.job_id
INNER JOIN msdb.dbo.sysjobsteps s
ON j.job_id = s.job_id AND h.step_id = s.step_id
WHERE h.run_status = 0 -- Failure
AND h.run_date > @FinalDate
ORDER BY h.instance_id DESC;



--Missing indexes

print N'Missing Indexes';


SELECT substring(so.name,1,40) AS Name
, (avg_total_user_cost * avg_user_impact) * (user_seeks + user_scans) as Impact
, ddmid.equality_columns
, ddmid.inequality_columns
, ddmid.included_columns
FROM sys.dm_db_missing_index_group_stats AS ddmigs
INNER JOIN sys.dm_db_missing_index_groups AS ddmig
ON ddmigs.group_handle = ddmig.index_group_handle
INNER JOIN sys.dm_db_missing_index_details AS ddmid
ON ddmig.index_handle = ddmid.index_handle
INNER JOIN sys.objects so WITH (nolock)
ON ddmid.object_id = so.object_id
WHERE ddmigs.group_handle IN (
SELECT TOP (5000) group_handle
FROM sys.dm_db_missing_index_group_stats WITH (nolock)
ORDER BY (avg_total_user_cost * avg_user_impact)*(user_seeks+user_scans)DESC);



--Duplicate indexes

print N'Duplicate Indexes';

DECLARE @SCHEMANAME VARCHAR(30);
DECLARE @TABLENAME VARCHAR(127);
WITH ind_list AS(
  select o.schema_id, i.object_id, i.index_id,
    i.name, i.type_desc,
    i.is_unique, i.is_primary_key, 
    STUFF( (SELECT ',' + tc.name
            FROM sys.index_columns ic
              JOIN sys.columns tc
               ON tc.column_id = ic.column_id AND
                  tc.object_id = ic.object_id
            WHERE ic.object_id = i.object_id AND
                  ic.index_id = i.index_id 
              AND ic.is_included_column = 0
            ORDER BY ic.index_column_id
            FOR XML PATH ('') ),1,1,'' ) index_columns,
    STUFF( (SELECT ',' + tc.name
            FROM sys.index_columns ic
              JOIN sys.columns tc
               ON tc.column_id = ic.column_id AND
                  tc.object_id = ic.object_id
            WHERE ic.object_id = i.object_id AND
                  ic.index_id = i.index_id
               AND ic.is_included_column = 1
            ORDER BY ic.index_column_id
            FOR XML PATH ('') ),1,1,'' ) include_columns
  FROM sys.indexes i
    JOIN sys.objects o ON o.object_id = i.object_id
  WHERE i.index_id > 0 AND i.type_desc <> 'XML'
    AND object_name(i.object_id) LIKE @TABLENAME
    AND i.is_disabled = 0 
    AND schema_name(o.schema_id) LIKE @SCHEMANAME )
SELECT substring(schema_name(included_indexes.schema_id),1,30) AS owner, 
  object_name(included_indexes.object_id) table_name,
  (SELECT SUM(st.row_count) FROM sys.dm_db_partition_stats st
   WHERE st.object_id = included_indexes.object_id
     AND st.index_id < 2 ) num_rows,
  included_indexes.name included_index_name, 
  included_indexes.index_columns included_index_columns, 
  included_indexes.include_columns
       included_index_include_columns,
  included_indexes.type_desc included_index_type, 
  included_indexes.is_unique included_index_uniqueness,
  included_indexes.is_primary_key included_index_PK,
  (SELECT SUM(a.total_pages) * 8 FROM sys.allocation_units a
    JOIN sys.partitions p ON a.container_id = p.partition_id
   WHERE p.object_id = included_indexes.object_id AND
     p.index_id = included_indexes.index_id
  ) included_index_size_kb,
  including_indexes.name including_index_name, 
  including_indexes.index_columns including_index_columns, 
  including_indexes.include_columns
       including_index_include_columns,
  including_indexes.type_desc including_index_type, 
  including_indexes.is_unique including_index_uniqueness,
  including_indexes.is_primary_key including_index_PK,
  (SELECT SUM(a.total_pages) * 8 FROM sys.allocation_units a
     JOIN sys.partitions p ON a.container_id = p.partition_id
   WHERE p.object_id = including_indexes.object_id AND
    p.index_id = including_indexes.index_id
  ) including_index_size_kb
FROM ind_list included_indexes
  JOIN ind_list including_indexes
    ON including_indexes.object_id = included_indexes.object_id
  JOIN sys.partitions ing_p 
   ON ing_p.object_id = including_indexes.object_id AND
      ing_p.index_id = including_indexes.index_id
  JOIN sys.allocation_units ing_a
   ON ing_a.container_id = ing_p.partition_id
WHERE including_indexes.index_id <> included_indexes.index_id
  AND LEN(included_indexes.index_columns) <= LEN(including_indexes.index_columns) AND included_indexes.index_columns + ',' = SUBSTRING(including_indexes.index_columns,1, LEN(included_indexes.index_columns + ',')) ORDER BY 2 DESC; --High index fragmentation check print N'Index with HIGH Fragmentation'; EXEC sp_MSforeachdb ' USE [?] SELECT ''?'' AS DB_NAME, QUOTENAME(sysind.name) AS [index_name], indstat.* FROM sys.dm_db_index_physical_stats (DB_ID(), NULL, NULL, NULL, ''LIMITED'') AS indstat INNER JOIN sys.indexes sysind ON indstat.object_id = sysind.object_id AND indstat.index_id = sysind.index_id where avg_fragmentation_in_percent >= 30
ORDER BY avg_fragmentation_in_percent DESC;
'

use master
GO


--Wait stats

print N'Wait Stats';

SELECT *
FROM sys.dm_os_wait_stats
where wait_time_ms > 10000
ORDER BY wait_time_ms DESC;


--Users and roles

print N'Users and Roles';

WITH Roles_CTE(Role_Name, Username)
AS
(
	SELECT 
		User_Name(sm.[groupuid]) as [Role_Name],
		user_name(sm.[memberuid]) as [Username]
	FROM [sys].[sysmembers] sm
)

SELECT  
    Roles_CTE.Role_Name,
    [DatabaseUserName] = princ.[name],
    [UserType] = CASE princ.[type]
                    WHEN 'S' THEN 'SQL User'
                    WHEN 'U' THEN 'Windows User'
                    WHEN 'G' THEN 'Windows Group'
                    WHEN 'A' THEN 'Application Role'
                    WHEN 'R' THEN 'Database Role'
                    WHEN 'C' THEN 'User mapped to a certificate'
                    WHEN 'K' THEN 'User mapped to an asymmetric key'
                 END
FROM 
    sys.database_principals princ 
JOIN Roles_CTE on Username = princ.name
where princ.type in ('S', 'U', 'G', 'A', 'R', 'C', 'K')
ORDER BY princ.name;


--Job information

print N'Job Information';


SELECT	 [JobName] = [jobs].[name]
		,[Category] = [categories].[name]
		,[Owner] = SUSER_SNAME([jobs].[owner_sid])
		,[Enabled] = CASE [jobs].[enabled] WHEN 1 THEN 'Yes' ELSE 'No' END
		,[Scheduled] = CASE [schedule].[enabled] WHEN 1 THEN 'Yes' ELSE 'No' END
		,[Description] = [jobs].[description]
		,[Occurs] = 
				CASE [schedule].[freq_type]
					WHEN   1 THEN 'Once'
					WHEN   4 THEN 'Daily'
					WHEN   8 THEN 'Weekly'
					WHEN  16 THEN 'Monthly'
					WHEN  32 THEN 'Monthly relative'
					WHEN  64 THEN 'When SQL Server Agent starts'
					WHEN 128 THEN 'Start whenever the CPU(s) become idle' 
					ELSE ''
				END
		,[Occurs_detail] = 
				CASE [schedule].[freq_type]
					WHEN   1 THEN 'O'
					WHEN   4 THEN 'Every ' + CONVERT(VARCHAR, [schedule].[freq_interval]) + ' day(s)'
					WHEN   8 THEN 'Every ' + CONVERT(VARCHAR, [schedule].[freq_recurrence_factor]) + ' weeks(s) on ' + 
						LEFT(
							CASE WHEN [schedule].[freq_interval] &  1 =  1 THEN 'Sunday, '    ELSE '' END + 
							CASE WHEN [schedule].[freq_interval] &  2 =  2 THEN 'Monday, '    ELSE '' END + 
							CASE WHEN [schedule].[freq_interval] &  4 =  4 THEN 'Tuesday, '   ELSE '' END + 
							CASE WHEN [schedule].[freq_interval] &  8 =  8 THEN 'Wednesday, ' ELSE '' END + 
							CASE WHEN [schedule].[freq_interval] & 16 = 16 THEN 'Thursday, '  ELSE '' END + 
							CASE WHEN [schedule].[freq_interval] & 32 = 32 THEN 'Friday, '    ELSE '' END + 
							CASE WHEN [schedule].[freq_interval] & 64 = 64 THEN 'Saturday, '  ELSE '' END , 
							LEN(
								CASE WHEN [schedule].[freq_interval] &  1 =  1 THEN 'Sunday, '    ELSE '' END + 
								CASE WHEN [schedule].[freq_interval] &  2 =  2 THEN 'Monday, '    ELSE '' END + 
								CASE WHEN [schedule].[freq_interval] &  4 =  4 THEN 'Tuesday, '   ELSE '' END + 
								CASE WHEN [schedule].[freq_interval] &  8 =  8 THEN 'Wednesday, ' ELSE '' END + 
								CASE WHEN [schedule].[freq_interval] & 16 = 16 THEN 'Thursday, '  ELSE '' END + 
								CASE WHEN [schedule].[freq_interval] & 32 = 32 THEN 'Friday, '    ELSE '' END + 
								CASE WHEN [schedule].[freq_interval] & 64 = 64 THEN 'Saturday, '  ELSE '' END 
							) - 1
						)
					WHEN  16 THEN 'Day ' + CONVERT(VARCHAR, [schedule].[freq_interval]) + ' of every ' + CONVERT(VARCHAR, [schedule].[freq_recurrence_factor]) + ' month(s)'
					WHEN  32 THEN 'The ' + 
							CASE [schedule].[freq_relative_interval]
								WHEN  1 THEN 'First'
								WHEN  2 THEN 'Second'
								WHEN  4 THEN 'Third'
								WHEN  8 THEN 'Fourth'
								WHEN 16 THEN 'Last' 
							END +
							CASE [schedule].[freq_interval]
								WHEN  1 THEN ' Sunday'
								WHEN  2 THEN ' Monday'
								WHEN  3 THEN ' Tuesday'
								WHEN  4 THEN ' Wednesday'
								WHEN  5 THEN ' Thursday'
								WHEN  6 THEN ' Friday'
								WHEN  7 THEN ' Saturday'
								WHEN  8 THEN ' Day'
								WHEN  9 THEN ' Weekday'
								WHEN 10 THEN ' Weekend Day' 
							END + ' of every ' + CONVERT(VARCHAR, [schedule].[freq_recurrence_factor]) + ' month(s)' 
					ELSE ''
				END
		,[Frequency] = 
				CASE [schedule].[freq_subday_type]
					WHEN 1 THEN 'Occurs once at ' + 
								STUFF(STUFF(RIGHT('000000' + CONVERT(VARCHAR(8), [schedule].[active_start_time]), 6), 5, 0, ':'), 3, 0, ':')
					WHEN 2 THEN 'Occurs every ' + 
								CONVERT(VARCHAR, [schedule].[freq_subday_interval]) + ' Seconds(s) between ' + 
								STUFF(STUFF(RIGHT('000000' + CONVERT(VARCHAR(8), [schedule].[active_start_time]), 6), 5, 0, ':'), 3, 0, ':') + ' and ' + 
								STUFF(STUFF(RIGHT('000000' + CONVERT(VARCHAR(8), [schedule].[active_end_time]), 6), 5, 0, ':'), 3, 0, ':')
					WHEN 4 THEN 'Occurs every ' + 
								CONVERT(VARCHAR, [schedule].[freq_subday_interval]) + ' Minute(s) between ' + 
								STUFF(STUFF(RIGHT('000000' + CONVERT(VARCHAR(8), [schedule].[active_start_time]), 6), 5, 0, ':'), 3, 0, ':') + ' and ' + 
								STUFF(STUFF(RIGHT('000000' + CONVERT(VARCHAR(8), [schedule].[active_end_time]), 6), 5, 0, ':'), 3, 0, ':')
					WHEN 8 THEN 'Occurs every ' + 
								CONVERT(VARCHAR, [schedule].[freq_subday_interval]) + ' Hour(s) between ' + 
								STUFF(STUFF(RIGHT('000000' + CONVERT(VARCHAR(8), [schedule].[active_start_time]), 6), 5, 0, ':'), 3, 0, ':') + ' and ' + 
								STUFF(STUFF(RIGHT('000000' + CONVERT(VARCHAR(8), [schedule].[active_end_time]), 6), 5, 0, ':'), 3, 0, ':')
					ELSE ''
				END
		,[AvgDurationInSec] = CONVERT(DECIMAL(10, 2), [jobhistory].[AvgDuration])
		,[Next_Run_Date] = 
				CASE [jobschedule].[next_run_date]
					WHEN 0 THEN CONVERT(DATETIME, '1900/1/1')
					ELSE CONVERT(DATETIME, CONVERT(CHAR(8), [jobschedule].[next_run_date], 112) + ' ' + 
						 STUFF(STUFF(RIGHT('000000' + CONVERT(VARCHAR(8), [jobschedule].[next_run_time]), 6), 5, 0, ':'), 3, 0, ':'))
				END
FROM	 [msdb].[dbo].[sysjobs] AS [jobs] WITh(NOLOCK) 
		 LEFT OUTER JOIN [msdb].[dbo].[sysjobschedules] AS [jobschedule] WITh(NOLOCK) 
				 ON [jobs].[job_id] = [jobschedule].[job_id] 
		 LEFT OUTER JOIN [msdb].[dbo].[sysschedules] AS [schedule] WITh(NOLOCK) 
				 ON [jobschedule].[schedule_id] = [schedule].[schedule_id] 
		 INNER JOIN [msdb].[dbo].[syscategories] [categories] WITh(NOLOCK) 
				 ON [jobs].[category_id] = [categories].[category_id] 
		 LEFT OUTER JOIN 
					(	SELECT	 [job_id], [AvgDuration] = (SUM((([run_duration] / 10000 * 3600) + 
																(([run_duration] % 10000) / 100 * 60) + 
																 ([run_duration] % 10000) % 100)) * 1.0) / COUNT([job_id])
						FROM	 [msdb].[dbo].[sysjobhistory] WITh(NOLOCK)
						WHERE	 [step_id] = 0 
						GROUP BY [job_id]
					 ) AS [jobhistory] 
				 ON [jobhistory].[job_id] = [jobs].[job_id];


--Existing linked server listing


print N'Linked Server Information';


declare @x int;
select @x = COUNT(name) 
from sys.all_objects
where name = 'Servers';
if @x <> 0
SELECT * 
--c.name, provider, data_source, is_remote_login_enabled, b.modify_date
FROM sys.Servers a
LEFT OUTER JOIN sys.linked_logins b ON b.server_id = a.server_id
LEFT OUTER JOIN sys.server_principals c ON c.principal_id = b.local_principal_id
where a.server_id <> 0;
else
exec sp_linkedservers;


Script review

script-review-blog

I have written dozens of scripts over the years and some of my favorites have been ones I created to reverse-engineer various database objects such as indexes and packages.  These scripts proved useful during difficult database migrations or when source code was needed to troubleshoot performance problems.

As Oracle tools and features have improved, I have used these scripts less and less, but every once in awhile, there is a situation when I have to reach back and put them to use once more.  Sometimes, though, they don’t work that well on newer versions of the Oracle database.  I then have to rework them to bring them up to speed.

One of these scripts is the one I use to reverse-engineer packages.  Originally, I used a temp table and output from dba_source to get the desired output.  Later on, I reworked this script to utilize the dbms_metadata.get_ddl function to get my output.  Last week, I noticed that this script wasn’t giving me the output I needed, so it was back to the drawing board.

When I first started using the dbms_metadata.get_ddl function, I was using a variable with a LONG datatype to store the returned value, then parsing the variable’s contents line-by-line.  It turns out that the actual datatype returned from that function is a CLOB.  I can only guess in my earlier version of my script that there was an implicit conversion happening.  My latest reworking of my package reverse-engineer script does a better job of converting CLOB data into something readable.  Since it uses the dbms_metadata.get_ddl function to return the desired object’s code, this script can be reworked to reverse-engineer other database objects such as indexes, tables, and procedures.  You can refer to the Oracle documentation on the dbms_metadata package to get more detail on the kinds of objects supported.

Keep in mind the number of objects you are trying to reverse-engineer.  In database environments with thousands of packages and procedures, such as EBS, it would be better to narrow the scope of the driving query.

————————————————————————————————————————–

–package_code_regenerate.sql
–Substitute the owner for a different schema or remove the where clause
–for the current schema

set pagesize 9999
set linesize 200
set wrap on

set serveroutput on size unlimited;
spool ./pg.out
declare
c clob;
——————————-
procedure printout
(p_clob in out nocopy clob) is
offset number := 1;
amount number := 32767;
len    number := dbms_lob.getlength(p_clob);
lc_buffer varchar2(32767);
i pls_integer := 1;
begin
if ( dbms_lob.isopen(p_clob) != 1 ) then
dbms_lob.open(p_clob, 0);
end if;
while ( offset < len )
loop
— If no more newlines are found, read till end of CLOB
if (instr(p_clob, chr(10), offset) = 0) then
amount := len – offset + 1;
else
amount := instr(p_clob, chr(10), offset) – offset;
end if;

— This is to catch empty lines, otherwise we get a NULL error
if ( amount = 0 ) then
lc_buffer := ”;
else
dbms_lob.read(p_clob, amount, offset, lc_buffer);
end if;
–dbms_output.put_line(‘Line #’||i||’:’||lc_buffer);
dbms_output.put_line(lc_buffer);
— This is to catch a newline on the last line with 0 characters behind it
i := i + 1;
if (instr(p_clob, chr(10), offset) = len) then
lc_buffer := ”;
–dbms_output.put_line(‘Line #’||i||’:’||lc_buffer);
dbms_output.put_line(lc_buffer);
end if;

offset := offset + amount + 1;
end loop;
if ( dbms_lob.isopen(p_clob) = 1 ) then
dbms_lob.close(p_clob);
end if;
exception
when others then
dbms_output.put_line(‘Error : ‘||sqlerrm);
end printout;
—————————
begin  –This is the driving query of the script
for x in (select owner, object_name
from dba_objects
where owner not like ‘%SYS%’
and object_type = ‘PACKAGE’)
loop
SELECT DBMS_METADATA.GET_DDL(‘PACKAGE’, x.object_name, x.owner) into c
FROM dual;
dbms_output.put_line(‘———–‘);
printout(c);
dbms_output.put_line(‘/’);
dbms_output.put_line(chr(10));
end loop;
end;
/

spool off

————————————————————————————————————————–

Working with Oracle external tables in a nutshell

It’s easy to create data sets using a text editor or a spreadsheet utility. With the latest version of these utilities, you can even make them up to a million rows. Once the data is created, it needs to be loaded into a database table or tables so that is can be utilized. Oracle has a couple of utilities for loading data from flat file – SQL Loader and external tables. SQL Loader can be a bit complicated to work with, so I prefer external tables for quickly loading data from flat files. Here’s a quick method I recently used.

I created a .csv file with 1048576 rows and 25 columns.  Here is the first comma-delimited record.  You can copy and paste it into a spreadsheet or a text file over and over, creating as any records as you like:

123456,This is a test,3.14,14-Dec-14,http://www.msn.com/en-us/autos/classic-cars/the-derelict-1952-chrysler-town-and-country-beauty-in-the-beast/ar-BBt2Y1e,123456,This is a test,3.14,14-Dec-14,http://www.msn.com/en-us/autos/classic-cars/the-derelict-1952-chrysler-town-and-country-beauty-in-the-beast/ar-BBt2Y1e,123456,This is a test,3.14,14-Dec-14,http://www.msn.com/en-us/autos/classic-cars/the-derelict-1952-chrysler-town-and-country-beauty-in-the-beast/ar-BBt2Y1e,123456,This is a test,3.14,14-Dec-14,http://www.msn.com/en-us/autos/classic-cars/the-derelict-1952-chrysler-town-and-country-beauty-in-the-beast/ar-BBt2Y1e

This is the table I created to hold the data in the Oracle 11.2.0.1 database (please excuse the lack of creative column names):

create table jontest.jontab(
 ID1              number,
 LABEL1     varchar2(15),
 PI1              number,
 DATE1       date,
 URL1          varchar2(500),
 ID2             number,
 LABEL2     varchar2(15),
 PI2             number,
 DATE2      date,
 URL2         varchar2(500),
 ID3            number,
 LABEL3    varchar2(15),
 PI3             number,
 DATE3      date,
 URL3         varchar2(500),
 ID4             number,
 LABEL4    varchar2(15),
 PI4             number,
 DATE4      date,
 URL4        varchar2(500),
 ID5            number,
 LABEL5   varchar2(15),
 PI5            number,
 DATE5     date,
 URL5       varchar2(500)
 );

Now that the target has been created, we need to set up the system for the external table process.  We need to create a directory object in the database using a directory where the oracle software account has read and write access:

create directory impdir as ‘/home/oracle’;

Make sure the table owner has read and write permission on this directory object:

grant read, write on directory impdir to jontest;

Place the input .csv file (called ironically input.csv) in the directory object location and ensure the ownership and permissions on the file are appropriate.

Next, create the external table to access the input file.  An external table is not actually a physical table in the database, but more like a view that allows access to the data in the file.  Note that this table was created as the ‘jontest’ user.

 

CREATE TABLE extload
 (
 ID1              char(6),
 LABEL1     char(15),
 PI1               char(4),
 DATE1        date,
 URL1          char(500),
 ID2             char(6),
 LABEL2     char(15),
 PI2              char(4),
 DATE2       date,
 URL2         char(500),
 ID3             char(6),
 LABEL3    char(15),
 PI3             char(4),
 DATE3      date,
 URL3         char(500),
 ID4            char(6),
 LABEL4   char(15),
 PI4            char(4),
 DATE4     date,
 URL4       char(500),
 ID5           char(6),
 LABEL5   char(15),
 PI5            char(4),
 DATE5     date,
 URL5       char(500)
 )
 ORGANIZATION EXTERNAL (
 TYPE ORACLE_LOADER
 DEFAULT DIRECTORY impdir
 ACCESS PARAMETERS (
 RECORDS DELIMITED BY NEWLINE
 FIELDS TERMINATED BY ‘,’
 MISSING FIELD VALUES ARE NULL
 (
 ID1              char(6),
 LABEL1     char(15),
 PI1              char(4),
 DATE1       char(10) date_format DATE mask “DD-MON-YY”,
 URL1         char(500),
 ID2            char(6),
 LABEL2    char(15),
 PI2             char(4),
 DATE2      char(10) date_format DATE mask “DD-MON-YY”,
 URL2        char(500),
 ID3            char(6),
 LABEL3   char(15),
 PI3           char(4),
 DATE3     char(10) date_format DATE mask “DD-MON-YY”,
 URL3       char(500),
 ID4          char(6),
 LABEL4  char(15),
 PI4           char(4),
 DATE4    char(10) date_format DATE mask “DD-MON-YY”,
 URL4      char(500),
 ID5          char(6),
 LABEL5  char(15),
 PI5           char(4),
 DATE5    char(10) date_format DATE mask “DD-MON-YY”,
 URL5      char(500)
 )
 )
 LOCATION (‘input.csv’)
 ) reject limit unlimited;

I used the same column names as my target table, again lacking any creativity in this area.  Notice that the column data types are either ‘char’ or ‘date’.  This just makes thing easier and the data can be transformed during the loading into the target table, as I will demonstrate.  You can already see in the second listing of the columns in this table that I am already formatting the date columns.

If the creation is successful, you should be able to perform a count on the number of records in the table, or select one of the column values.  If the count or select comes back with no records or errors, check the directory object location for .bad or .log files with the table name as the prefix of the file name.  These files are created by default even though we did not specify them in the external table creation statement.

Once you can select from the external table, you can treat it like any other read-only table.  We can now perform any data conversion while we load our target table.

insert into jontest.jontab
 select
 to_number(ID1,999999),
 LABEL1,
 to_number(PI1,9.99),
 to_date(DATE1,’DD-MON-YY’),
 URL1,
 to_number(ID2,999999),
 LABEL2,
 to_number(PI2,9.99),
 to_date(DATE2,’DD-MON-YY’),
 URL2,
 to_number(ID3,999999),
 LABEL3,
 to_number(PI3,9.99),
 to_date(DATE3,’DD-MON-YY’),
 URL3,
 to_number(ID4,999999),
 LABEL4,
 to_number(PI4,9.99),
 to_date(DATE4,’DD-MON-YY’),
 URL4,
 to_number(ID5,999999),
 LABEL5,
 to_number(PI5,9.99),
 to_date(DATE5,’DD-MON-YY’),
 URL5
 from jontest.extload;