Monday, November 19, 2018

How to use rman to create a backup-based clone on a remote server


It has been a while since I needed to use this technique, since we rely on storage snapshot clones these days. Sometimes though, a good old-fashioned rman clone based on backups is the only way to solve a problem.
Since I always avoid working on the production server during cloning, most steps are done logged onto the auxiliary server.

The method I used is based on "Backup-Based Duplication Without a Target Database and Recovery Catalog Connection"
Here is what I did:

1. On the production server, backup of the source database using RMAN:
rman target / nocatalog
backup database plus archivelog;

From this point and onwards, everything is done while logged onto the destination server.

2. Get the files from the source server:
ssh testserver
cd /u05
mkdir bup
cd bup
scp -r prodserver:/u05/flash_recovery_area/PRODDB01/2018_11_16/* .

3. Prepare the auxiliar pfile. Note that the parameters I use exceeds the actual required parameters.
But since the auxiliary instance will replace an already existing database instance, which is already tuned and has the correct memory parameters, I choose to include them. Notice also the db_file_name_convert and log_file_name_convert parameters. They control where rman will place the files during the restore process.
cd $ORACLE_HOME/dbs
vi inittest1.ora

Add the following:

*.db_name='test1'
*.db_unique_name='test1'
*.audit_file_dest='/u01/oracle/admin/test1/adump'
*.audit_trail='DB'
*.compatible='12.2.0'
*.control_files='/u02/oradata/test1/control01.ctl','/u04/fra/test1/control02.ctl'
*.db_block_size=8192
*.db_file_name_convert='proddb01','test1'
*.log_file_name_convert='proddb01','test1'
*.db_recovery_file_dest='/u05/flash_recovery_area/test1'
*.db_recovery_file_dest_size=1000G
*.diagnostic_dest='/u01/oracle'
*.nls_language='NORWEGIAN'
*.nls_territory='NORWAY'
*.open_cursors=300
*.optimizer_adaptive_plans=FALSE
*.optimizer_dynamic_sampling=0
*.optimizer_mode='ALL_ROWS'
*.pga_aggregate_target=7222M
*.processes=1500
*.remote_login_passwordfile='EXCLUSIVE'
*.sga_target=21696M
*.shared_pool_size=2624M
*.streams_pool_size=256M
*.undo_tablespace='UNDOTBS1'
*.diagnostic_dest=/u01/oracle

4. I prefer using an spfile over a pfile. Therefore I take the time here to create an spfile:
sqlplus / as sysdba
startup nomount pfile=inittest1.ora
create spfile from pfile;

5. Startup the auxiliary instance in nomount-mode using the spfile:
shutdown abort
startup nomount

6. Start the duplication process:
rman auxiliary /
duplicate database to test1
backup location '/u05/fra/bup';

RMAN went through the normal restore, name switching and recovery phases. Finally, the database was opened with the resetlog option.

Wednesday, November 14, 2018

New parameter in dbms_redefinition.finish_redef_table in 12c



Oracle 12c adds a potentiall very useful feature to the dbms_redefinition package, in the procedure finish_redef_table: dml_lock_timeout

It specifies a time limit in seconds for how long a DML statment waits in a DML lock queue, before the procedure terminates gracefully.

By default, this parameter is set to 0 which means no waiting at all; the procedure will simply error out if it cannot get a lock on the table.

The maximumm value is 1000000 and will cause any DML statements to wait in perpetuity to aquire a DML lock.

Here is an example of its usage, where I have set the limit to 5 minutes (300 seconds):
BEGIN
DBMS_REDEFINITION.FINISH_REDEF_TABLE(uname=>'SCOTT',
                                     orig_table=>'EMP',
                                     int_table=>'EMP_INTERIM', 
                                     dml_lock_timeout=>300);
END;
/

Monday, October 29, 2018

How do you configure an Oracle Golden Gate extract to run in Integrated Capture Mode?

There are different parameters valid for Golden Gate extracts, depending on which mode you choose (integrated mode or classical mode).

* Integrated extract parameters are found here
* Classical extract parameters are founnd here

Some of the parameters can be used in both configuration, while others are specific to one or the other.

An example of a parameter that is unique for Integrated Capture mode, is
TRANLOGOPTIONS INTEGRATEDPARAMS( option, ...)

You instruct the Golden Gate software to start your extract in Integrated mode by the following ggsci commands:

ADD EXTRACT MYEXT INTEGRATED TRANLOG, BEGIN NOW

To instruct the Golden Gate software to start the same extract in classical mode, alter the instructions slightly:
ADD EXTRACT MYEXT, TRANLOG, BEGIN NOW

Potential solution to Golden Gate error message "Parameter [INTEGRATEDPARAMS] is not valid for this configuration"


I was trying to set up an Integrated Capture in my Golden Gate environement, and kept getting the following error when starting my extract process:

OGG-10144  Oracle GoldenGate Capture for Oracle, myext.prm:  (myext.prm) line 3: Parameter [INTEGRATEDPARAMS] is not valid for this configuration.
ERROR   OGG-01668  Oracle GoldenGate Capture for Oracle, myext.prm:  PROCESS ABENDING.

In my case, this was caused by the fact that the extract was configured with classical capture, like this:

ADD EXTRACT MYEXT, TRANLOG, BEGIN NOW

The correct way to configure an extract in integrated capture mode is:

ADD EXTRACT MYEXT INTEGRATED TRANLOG, BEGIN NOW

How to lookup parameter definitions in Golden Gate 12.2


A potentially very useful feature when working with Golden Gate configurations is the ability to lookup parameter definition usage, with the new command

GGSCI (myserver.mydomain.com as ggadmin@testdb01) 31> info param tranlogoptions.INTEGRATEDPARAMS

param name  : tranlogoptions.integratedparams
description : (Oracle) Valid for Extract in integrated capture mode (Oracle Standard or Enterprise Edition 11.2.0.3 or later) 
Passes parameters and values to the Oracle database logmining server when Extract is in integrated capture mode.
argument    : no argument
options     : ANNOTATEDDLSIZE, CAPTURE_IDKEY_OBJECTS
              CAPTURE_SEQUENCE_NEXTVAL, DISABLE_ON_LIMIT
              DOWNSTREAM_REAL_TIME_MINE, ENABLE_PROCEDURAL_REPLICATION
              IGNORE_TRANSACTION, IGNORE_UNSUPPORTED_TABLE, INCLUDE_OBJECTS
              INLINE_LOB_OPTIMIZATION, INLINE_SFLOB_OPTIMIZATION, MAXIMUM_SCN
              MAX_SGA_SIZE, MERGE_THRESHOLD, MESSAGE_LIMIT
              MESSAGE_TRACKING_FREQUENCY, PARALLELISM
              SKIP_AUTOFILTERED_TABLE_DDL, SPLIT_THRESHOLD, STARTUP_SECONDS
              TIME_LIMIT, TRACE_LEVEL, USE_RAC_SERVICE, WRITE_ALERT_LOG
              XOUT_CLIENT_EXISTS
component(s): EXTRACT
mode(s)     : Integrated Extract
platform(s) : AIX
              HPUX-IT
              HPUX-PA
              Linux
              Solaris SPARC
              Solaris x86
              Windows x64
versions    :
    max ver : 12.3.0.1.85
database(s) : all supported databases (on the supported platforms).
status      : current
mandatory   : false
dynamic     : false
relations   : none

Source: http://www.oracle-scn.com/oracle-goldengate-12-2-new-feature-info-param/

Friday, October 26, 2018

How to avoid OGG-10470 during and "add trandata" operation

When configuring a table for an Oracle GoldenGate replication, you need to enable supplemental logging for the table.

If you see the following message at the end of ADD TRANDATA command in ggsci:
GGSCI (myserver.mydomain.com as gg@testdb01) 8> ADD TRANDATA SCOTT.EMP

2018-10-25 11:59:35  INFO    OGG-15132  Logging of supplemental redo data enabled for table SCOTT.EMP.

2018-10-25 11:59:35  INFO    OGG-15133  TRANDATA for scheduling columns has been added on table SCOTT.EMP.

2018-10-25 11:59:35  INFO    OGG-15135  TRANDATA for instantiation CSN has been added on table SCOTT.EMP.

2018-10-25 11:59:35  ERROR   OGG-10470  Error encountered during gathering support information on table SCOTT.EMP.
ERROR: OCI Error ORA (status = 942-ORA-00942: table or view does not exist)

You need to grant access to the dictionary for your golden gate databaser user. In my case:
GRANT SELECT ANY DICTIONARY TO GG; 

From now on, any attempt to add supplemental logging for tables will end without errors, like this:

2018-10-26 13:01:41  INFO    OGG-10471  ***** Oracle Goldengate support information on table SCOTT.EMP. *****
Oracle Goldengate support native capture on table SCOTT.EMP.
Oracle Goldengate marked following column as key columns on table SCOTT.EMP: EMP_ID.

How to add supplemental logging on a table

alter table scott.emp 
add supplemental log group gg_feed (feed_id) always;

To reverse:
alter table scott.emp
drop supplemental log group gg_feed;