Tag Archives: Database

SYSAUX LOB segment for auditing bug not released in Standard Edition


Last week we were struck by an issue, which turned out to be a bite from a bug!
SYSAUX table-space had quickly filled up to the “my data-file is full”-limit, which in the end was fixed by adding a data-file.

Strange thing though, that for a very small footprint database, we now have a very big SYSAUX table-space.

Some investigation brought me to the Unified Auditing being standard active in database 12c (you can read up on that background with my friend Ann Sjökvist here).
We are faced though with a different (and possibly a little more obscure) Bug 20077418 – RECLAIMING THE SECUREFILE LOB SEGEMENT IN 12.1 Standard Edition.
What this bug boils down to is the following:
There is a lot of audit data recorded by default, the ORA_SECURECONFIG profile is running out of the box. I haven’t taken the time to figure exactly out what is written, where and how, but I know it involves a LOB segment (SYS_LOB0000091833C00014$ by SYSAUD) which is, in our case in comparison to the total database size, HUGHE!! The management of this audit data, usually driven by DBMS_AUDIT_MGMT, has absolutely no effect on this segment (at least not on shrinking it).

Searching for the mentioned bug you just find to EE bugs (18109788 & 22272580) but they at least they give _some_ clues… The actual bug is undisclosed and in status 11 (being worked on).
In the end it means that auditing is fine, even in SE, but, for the moment, restrain yourself… The data you gather cannot be managed (yet). And for the rest:

If
select policy_name
from audit_unified_enabled_policies
;

yields any results, consider switching this auditing off (eg.SQL> noaudit policy ORA_SECURECONFIG;)

Hope this helps…


#DBADev (Ops), who knows what is going on…

I have been considering writing this article for quite some time now.
APEX Connect 2016 in Germany’s capital Berlin and the DOAG Database days have finally persuaded me to talk more about #DBADev, let me explain why…

Whenever in the stone age…

During my career as DBA, I was always working closely together with Oracle Forms & Reports developers. In retrospect, the cooperation in that time was remarkable.
These Forms & Reports developers had always been used to working on a host-based platform.

For those of you who actually remember Oracle Forms & Reports and wonder…
Was there ever Forms & Reports host based?
Yes there was, but it is creepily long ago!!

Because of the nature of Forms & Reports, there always was a lot of consideration about where to place application code. This especially became true when PL/SQL was introduced and the migration to Oracle Forms & Reports 6.5 came about.
This brought the transition to client/server based computing and introduced physical distance between the database and the “front-end”.
Front-end between quotation marks, as in today’s world we don’t actually know “front-end” anymore in this same qualification. The “Frond-end” was always more elegantly and fittingly described as a “fat-client”, because of the sheer size of the software and utilities that were required on the end-users workstation.

The physical separation and distance between the presentation entity and the data manipulation engine required and inspired a lot of thought and debate on where the bulk of data processing had to be done.
You can imagine the impact of having a specific data manipulation done inside an Oracle Form that lived on a desktop on the other end of the network. Especially when the required data set is large. Having 1,000 records being fetched, where 2 where manipulated and then send back in bulk, repeated 100 times, 4 times a minute on a 10 Mbps network. OK, clear, that needs to be done smarter.
The solution: work with small data sets and do database side manipulation to limit client/server communication. And actually, that worked quite well!!

All good and fine… But how does this tie in to #DBADev? This already sounds so harmonious. And how could APEX Connect 2016 have inspired this article?

Well… Let’s see

Later on, I found that this cooperation appeared to be not so normal.
If you step out of the world of client-server computing and move on to “todays world”, that started more or less in the nineties with web based computing – or cloud-computing “avant la lettre“ or “my stuff on your computer” or however you describe it – you find a world that consists of “strange things”.
I find these things “strange things” because I believe they are suboptimal, and luckily I find myself not alone in this corner.
Suboptimal in a way that data manipulation solutions (lets call them applications for now) should be considered to be database agnostic. This independence dictates that you use the database as just a data store or even more accurately, as a persistency store. Blane Carter 2 minute TechTip

In another scenario these applications are designed and build by developers who are very good at creating intuitive and sharp looking user interfaces. Unfortunately often with a lesser developed understanding of the mechanics involved in dishing up and serving data to this newly established middle tier.

With the continuing professionalization of IT over the past 20 years, we have seen the creation of a wide variety of disciplines. These range from those who think about IT (architects, managers, designers) to those who build IT (programmers, engineers) to those who run IT (system administrators, operators) and the majority of these disciplines today are self-contained groups of professionals and specialists who excel at their own game. Basically that is good as the profession is wide and complex enough to support this.
The problem is that there is no longer anyone who has the whole picture.

Bring it on / together!

apex-logoAPEX Connect 2016, to me personally, was the first time I really saw #DBADev in practice. With the following two examples I want to illustrate my inspiration.

The first talk of this genre was @alexnuijten with his confessions, and subsequent smart tips and best practices in “Structuring an APEX application”.
As a pure database developer like Alex, you are automatically more prone to thinking about “DBA-stuff”. A lot of these best practices, although they are very database centric, like using a view for each application screen, are obviously primarily there to help the developer. And, don’t get me wrong, that is a very good thing! Alex inspires to try and combine the best of both worlds, which helps getting the most out of your application, your database, and therewith frankly, out of your total investment.

The second example was the information-packed presentation by Dietmar Aust @daust_de, called “Oracle APEX Scripting – die Kommandozeile ist Dein Freund“ (the command line is your friend).
Much more than “just about developing”, this presentation bridged gaps in more than one way. Perhaps it is even #DBADevOps if you think about it.

The recent DOAG Database days held a few additional surprises with the presence of @cczarski and @nielsdb. A very will pitched presentation by Bruno Cirone really sparked the growing interest in the topic!!

It is funny how an idea that was initiated some 18 months ago, conceived together with Sabine Heimsath @flederbine has grown and evolved out of natural demand. For me, this is one other aspect of the industry, where APEX is setting new frontiers.
With a growing awareness and more people recognizing the gap, the deficits it is bringing and the benefits cooperation brings, I have good hopes.

APEX is not only the technology that enables you to create web-based apps super quickly, it is also the technology that brings developers and DBA’s truly closer to each other, ensuring a maximum bang for the buck when it comes to utilizing your database infrastructure investments!
I am not saying we are there, but this is definitely a first step in the right direction!

DBA_FEATURE_USAGE_STATISTICS and SE2

This blog post is inspired on work I have been doing on Standard Edition databases and the returning confusion about what is and what is not part of Standard Edition.

DBA_FEATURE_USAGE_STATISTICS is a tool in determining license usage for the Oracle database. It is good to understand the implications of each entry, know what is happening in your database and thus be able to have a substantial conversation about the usage of your license, being SE, SEO, SE2 or EE!

This list is the full list of DBA_FEATURE_USAGE_STATISTICS and I have found no source where there is a mapping of these features to database editions. As it is a lot of tedious work I call upon the community to help complete the list and make it as accurate as can be. So, if you have news, improvements, other bits of information, please send it to me and I will make sure it gets added!

WARNING: Still… with all the work that goes into these answers, it is not the law, it is a very serious interpretation of facts which will pay a part in helping you make the right decision when it comes to database licensing.

Feature Standard Edition
Active Data Guard – Real-Time Query on Physical Standby NO !
ADDM NO !
Advanced Replication NO !
Application Express YES
ASO native encryption and checksumming NO – EE option !
Audit Options NO !
Automatic Maintenance – Optimizer Statistics Gathering YES
Automatic Maintenance – Space Advisor YES
Automatic Maintenance – SQL Tuning Advisor NO !
Automatic Memory Tuning
Automatic Segment Space Management (system) YES
Automatic Segment Space Management (user)
Automatic SGA Tuning YES
Automatic SQL Execution Memory YES
Automatic SQL Tuning Advisor NO !
Automatic Storage Management
Automatic Undo Management
Automatic Workload Repository
AWR Baseline NO !
AWR Baseline Template NO !
AWR Report NO !
Backup BASIC Compression
Backup BZIP2 Compression
Backup Encryption
Backup HIGH Compression
Backup LOW Compression
Backup MEDIUM Compression
Backup Rollforward
Backup ZLIB Compression
Baseline Adaptive Thresholds
Baseline Static Computations
Bigfile Tablespace
Block Media Recovery NO !
Change Data Capture NO !
Change-Aware Incremental Backup
Character Semantics
Character Set
Client Identifier
Clusterwide Global Transactions
Compression Advisor
Crossedition Triggers
CSSCAN
Data Guard NO !
Data Mining NO – EE option !
Data Recovery Advisor
Database Migration Assistant for Unicode
Database Replay: Workload Capture NO ! 1
Database Replay: Workload Replay NO ! 1
DBMS_STATS Incremental Maintenance
Deferred Open Read Only
Deferred Segment Creation NO !
Direct NFS
Dynamic SGA
Editioning Views
Editions
EM Database Control
EM Grid Control
EM Performance Page
Encrypted Tablespaces
Exadata
Extensibility
File Mapping
Flashback Data Archive NO ! 2
Flashback Database NO !
GoldenGate NO – EE option ! 3
HeapCompression
Hybrid Columnar Compression NO !
Instance Caging NO !
Internode Parallel Execution
Job Scheduler
Label Security NO – EE option !
LOB
Locally Managed Tablespaces (system) YES
Locally Managed Tablespaces (user)
Locator YES
Logfile Multiplexing
Long-term Archival Backup
Materialized Views (User) NO !
Messaging Gateway NO !
MTTR Advisor
Multi Section Backup
Multiple Block Sizes
Object
OLAP – Analytic Workspaces NO – EE option !
OLAP – Cubes NO – EE option !
Oracle Database Vault NO – EE option !
Oracle Java Virtual Machine (system) YES
Oracle Java Virtual Machine (user)
Oracle Managed Files
Oracle Multimedia
Oracle Multimedia DICOM
Oracle Secure Backup
Oracle Text
Oracle Utility Datapump (Export)
Oracle Utility Datapump (Import)
Oracle Utility External Table
Oracle Utility Metadata API
Oracle Utility SQL Loader (Direct Path Load)
Parallel SQL DDL Execution NO !
Parallel SQL DML Execution NO !
Parallel SQL Query Execution NO !
Partitioning (system) YES
Partitioning (user) NO – EE option !
PL/SQL Native Compilation
Quality of Service Management NO !
Read Only Tablespace
Real Application Clusters (RAC) YES 4
Real-Time SQL Monitoring
Recovery Area
Recovery Manager (RMAN) YES
Resource Manager NO !
Restore Point
Result Cache NO !
RMAN – Disk Backup
RMAN – Tape Backup
Rules Manager
SecureFile Compression (system) YES
SecureFile Compression (user)
SecureFile Deduplication (system) YES
SecureFile Deduplication (user)
SecureFile Encryption (system) YES
SecureFile Encryption (user)
SecureFiles (system) YES
SecureFiles (user)
Segment Advisor (user)
Segment Shrink
Semantics/RDF NO !
Server Flash Cache
Server Parameter File
Services
Shared Server
Spatial NO – EE option !
SQL Access Advisor
SQL Monitoring and Tuning pages NO – EE option !
SQL Performance Analyzer NO !
SQL Plan Management NO !
SQL Profile
SQL Repair Advisor
SQL Tuning Advisor
SQL Tuning Set (system) YES
SQL Tuning Set (user)
SQL Workload Manager
Streams (system) YES 5
Streams (user)
Transparent Data Encryption
Transparent Gateway YES – option
Transportable Tablespace NO ! 6
Tune MView
Undo Advisor
Very Large Memory
Virtual Private Database (VPD) NO !  7
Workspace Manager
  1. Unless used for upgrade to Enterprise Edition.
  2. Unless used without history table optimization.
  3. Goldengate can also be used with Standard Edition, it is a separate product.
  4. RAC on Enterprise Edition is an option.
  5. No capture from redo.
  6. Import transportable tablespaces in all editions.
  7. Policies on XDB$ACL$xd_sp in sys.v_$vpd_policy are internal ( “out of the box”) policies that are used by XDB to control the access to certain internal tables. All the logic is implemented in the xdb.DBMS_XDBZ package and there is no way one can control / influence the way this is working.

@HrOUG_2015 in Rovinj, Croatia

In a hectic year it is good to attend and contribute to Oracle user group sessions. This adds an element of a ‘Working Holiday’ to someones schedule. I can promise you, the vacation isle of Rovinj is a perfect venue for this and especially since it is the last week of the opening of the Hotel for this season.
Of course you can find all information about contributing to these events right here!!

@HrOUG_2015, as the official twitter-account of the conference goes, brings just this!! Content combined with pleasure. Ranging from quality sessions by Rock star speakers to relaxation in the pool and late night party in “The Castle”.

Currently the biggest worry is rain… At least for the attendees. As always the (very) hard working organizers are doing their best to create a super experience for everyone attending the conference, and my personal biggest worry is that the participants will actually bring their laptop to the hands-on experience. Actually doing logical replication yourself is so much cooler than seeing it demonstrated. It will be an interesting experience anyhow.

This conference also led to another series of Oracle Hero’s I got to meet in person!

And as always there is really serious stuff going on as well. One of the main challenges or worries today is the developments surrounding Oracle Database Standard Edition Two, and the impact it brings for the development of the European market.
Eliminating this database version forces emerging projects to use the Oracle Cloud, as the super-sharp priced project startup version is no longer available. We had this with Standard Edition One. It also counters Oracles own statement, quite recently presented by Andrew Sutherland, of hybrid cloud functionality, since there is no “on-premise” equivalent for a small scale project anymore!
We are hoping for a good discussion on Friday during the Standard Edition Round Table version at HrOUG, co-hosted by Philippe Fierens, as this development is very heartfelt in Croatia as it is in many European countries.

If you want to read more about this years event in Croatia, please checkout the many tweets and facebook entries by @helifromfinland, @alexnuijten, @roelhartman (ps. Vote for Roel as member of the ODTUG board) and many more!!

Oh, and as far a basic life’s needs go… The Internet on the island is the best ever!!

dbms_redefinition houskeeping

dbms_redefinition actually is a nifty, but powerful little toolkit that let’s you change table-definitions without actually locking the table in such a manner that it would prevent regular operations from being interrupted.

You can read loads about it in the Oracle documentation or in the wealthy library by Mr. Tim Hall.

housekeepingOne thing I noticed, and which I want to share here has lots to do with the house keeping that is automatically done by dbms_redefinition. Actually it talks about some of the bits it didn’t brush up after itself.

dbms_redefinition works using triggers and materialized views to help switch from your current active production table, via a so-called interim table, back to your shiny new, redefined production table. You can follow this beautifully by querying the dba_segments view along the way.
For this it obviously creates this materialized view and the other required components and it removes them after you finish your redefinition-trip. After all that is done, you can just remove your interim table and be done with it.

At least, that is what happened in most of the cases and is what you would expect!

Though, in some cases… it proved impossible to drop the interim table. To me this was somewhat scary… did the redefinition not finish, or did it not finish correctly?

What happened?

There was this table that I redefined. It had referential integrity constraints (aka. foreign key constraints) pointing towards it. Of course dbms_redefinition neatly created version of these to the interim table to be sure nothing went wrong.build-in-flight

When finishing redefinition (with dbms_redefinition.finish_redef_table) most of the interim bits and pieces are cleared away and you just have to drop your interim table manually (okay, we can discuss if this actually would / could / should be automated, but let’s leave that).

But… when you are then manually dropping this interim table (in a busy production system, I tend to want to be careful and just issue ‘drop table int_<tablename>‘. That does not work. dbms_redefinition “forgets” to remove these referential integrity constraints in the other tables (which are neatly names tmp$$_<constraintname>).
This than means either issue ‘drop table int_<tablename> cascade constraints‘, which is more then the basic ‘drop table‘ or find these constraints and remove them manually first:

select 'alter table '||owner||'.'||table_name||' drop constraint '||constraint_name||';'
from dba_constraints dc
where constraint_type='R'
and r_constraint_name in
(
select constraint_name
from all_constraints
where table_name = 'INT_<tablename>'
);
alter table <schema>.<foreign table> drop constraint TMP$$_<constraint name>;

I guess, personally, I would like dbms_redefinition to do this for me…

It’s smart enough! it created them!

Just a quick and additional note, setting ddl_lock_timeout to 30 or 60 for your session can actually help and prevent a lot of non-sense on a busy system.

Hope this helps someone sometime 😉

Introducing FETCHER in a running replication process

This is no regular bit of work and it will probably (and hopefully) never hit you in a production setup…

The prerequisite is that you know how on-line data replication in general, and Dbvisit Replicate specifically, work.

The following case is true:
I had half of a replication pair running.
It means that the MINE process was running, converting REDO-log in PLOG-format. The APPLY process had not yet started because the target database was still being prepared.

dbvisit-replicate-logical-replication-made-easy-18-638-300x225The reason for this is that we needed to start converting redo-log information to PLOG information while we were setting up the target environment. The reason for that was that the setup (exporting source, copying dump to target and importing) was taking quite a bit of time, which would impact redo-log storage to heavily in this specific situation.

It was my suspicion that the MINE process was unable to get enough CPU-cycles from the production server to actually MINE more redo-log seconds than wall-clock seconds passed. In effect, for every second of redo-log information that was mined, between 1 and 6 seconds passed.

This means that the replication is lagging behind and will never be able to catch up.

To resolve this, the plan was to take the MINE process of the production server and placed on an extra server. On the production server, a process called FETCHER would be introduced. The task of this process is to act as a broker between the database and the MIN process, forwarding the requested on-line an archived redo log files.

Normally (!) you would use the nifty opportunities that Replicate offers with the setup wizard and just create a new setup. And actually, this is what I used to figure out this setup. And, if you can, please do use this…

Why didn’t I then, you would rightfully ask?

Well… The instantiation process would take to long, and did I say we were under time-pressure?

  • Setup wizard, 5 minutes
  • The famous *-all.sh script, ~ 1 hr.
  • Datapump Export, ~ 10 hrs.
  • Copy from DC old to DC new,  ~ 36 hrs.
  • Datapump Import, ~ 10 hrs.

So, totally we could spend 57:05 hrs. to try to fix this on the go…

Okay, here we go:

Note: cst-migration is the name of the replication project as you specified it in setup wizard when setting up Replication.

TIP: When setting up on-line replication, it is worth your effort to create separate tnsnames.ora entries for your project, like ‘repl-source’ and ‘repl-target’ acros all nodes.
It can get hellishly confusing if you have, as in this case, a database that is called <cst> and is called the same on the source and target server!

1. Step one:
We obviously had the ./cst-migration/config directory from our basic setup with just MINE & APPLY. This directory holds (among others) the ./cst-migration/config/cst-migration-ontime.ddc file. This file holds the Dbvisit Replicate Repository contents that is needed to run the processes.

From this setup, MINE is actually running. We actually concluded the fact that we were not catching up from this process.

2. Step two:
Now we run dbvrep -> setup wizard again and create a Replicate setup directory with FETCHER and isolate the ./cst-migration+fetcher/config/cst-migration+fetcher-onetime.ddc.

By comparing the two files, I was able to note the differences and therewith conclude the changes necessary to introduce a FETCHER process. It is a meticulous job to make sure all the paths on all the three servers are correct, that port numbers are correct and that all the individual steps are take in the right order. This is the overview.

Having these changes, it is all downhill from now.

3. Step three:
Using the Dbvisit Replicate console, the new entries and the changes were made to the DDC-information stored in the Replicate repository. You can enter these manually or execute your change-file by executing @<change-file-name> inside the console.

4. Step four:
Create the ./cst-migration directory on the system you will use for the relocated MINE process and copy the cst-migration-MINE.ddc and cst-migration-run-source-node.sh in this directory.
Rename the cst-migration-run-source-node.sh to cst-migration-run-mine-node.sh to reduce confusion.
Make sure that the paths mentioned in the cst-migration-MINE.ddc are correct for the system you are starting it on!

NOTE: Please make sure that you can reach both the source and the target database from this node using the tnsnames-entries you have created for the replication setup.

5. Step five:
Rename the cst-migration-MINE.ddc on the source node (!) to cst-migration-FETCHER.ddc and change the cst-migration-run-source-node.sh file to start the FETCHER process in stead of MINE process.

You are now ready to start your new replication processes!

NOTE: If you are running APPLY already, there are some additional things you need to be aware of.

Although it was not the case when I came across this challenge, I am happy to say that Dbvisit have verified and accepted this solutions as a supported action.

Hope this helps.

My picks, no, Agenda… for UKOUG_Tech15

I went over the agenda for UKOUG_Tech15 and took my picks & suggestions.
Then I thought, why not share these…

MONDAY

The Oracle Database In-Memory Option: Challenges & Possibilities
Christian Antognini – Trivadis AG

Standard Edition Something for the Enterprise or the Cloud?
Ann Sjökvist – SE – JUST LOVE IT

All about Table Locks: DML, DDL, Foreign Key, Online Operations,…
Franck Pachot – DBi Services

Silent but Deadly : SE Deserves Your Attention
Philippe Fierens – FCP
Co-presenter(s): Jan Karremans – JK-Consult (Having a link here would be silly, right)

Oracle SE – RAC, HA and Standby are Still Available. Even Cloud!
Chris Lawless – Dbvisit

SE DBA’s Life a Bed of Roses?
Ann Sjökvist – SE – JUST LOVE IT

Oracle Standard Edition Round Table
Joel Goodman – Oracle
Co-presenter(s): Ann Sjokvist, Philippe Fierens, Jan Karremans

TUESDAY

Watch out for #RepAttack… all day long!!
And earn your RepAttack badge-ribbon…

Advanced ASH Analytics: ASHmasters
Kyle Hailey – Delphix

Community Keynote – Dominic Giles

Oracle BI Cloud Service – Moving Your Complete BI Platform to the Cloud
Mark Rittman – Rittman Mead

Infiniband for Engineerd Systems
Klaas-Jan Jongsma – VX Company

Oracle Database In-Memory Option – Under the Hood
Maria Colgan – Oracle

Do an Oracle Data Guard Switchover without Your Applications Even Knowing
Marc Fielding – Pythian

Using Oracle NoSQL to Prioritise High Value Customers
James Anthony – RedStack tech

WEDNESDAY

HA for Single Instance Databases without Breaking the Bank
Niall Litchfield – Markit

Database Password Security
Pete Finnigan – PeteFinnigan.com

Connecting Oracle & Hadoop
Tanel Poder – PoderC LLC

Enterprise Use Cases for Internet of Things
Lonneke Dikmans – eProseed
Co-presenter(s): Luc Bors – eProseed

Bad Boys of On-line Replication – Changing Everything
Bjoern Rost – portrix Systems GmbH
Co-presenter(s): Jan Karremans – JK-Consult

RMAN 12c Live : It’s All About Recovery,Recovery,Recovery
René Antúnez – Pythian

Hopefully it will attend you to some interesting session for you!

Kscope15, a celebration of tech…

Kscope15 promised to be a brand new experience in more than one way.

Kscope15LogoAs I start to write this report, I am flying from Düsseldorf airport to Atlanta. It will be the first time flying to the United States with a stopover, and because of Erik van Roon, I came prepared. With just carry-on luggage, I should end up at my final destination, Fort Lauderdale, Florida, together with my ‘stuff’. I am flying Delta Airlines this time, and for an airline that promises just a ‘lunch’ during the 9 hours flight, they do come up with a lot of food…

My colleagues of FOEX have already arrived at the event-venue and are setting up our booth.

On arrival at Fort Lauderdale airport, I am scheduled to meet-up with distinguished product manager for PL/SQL and EBR, Bryn Llewellyn. From there, we would travel to Hallandale Beach to check into our hotels. This plan was only hindered by sheer force of wind shear at Atlanta International, which delayed my flight.

The first day, the Sunday, started off with a boiling walk to the Diplomat hotel. Upon registration I was pleasantly surprised that FOEX had graciously upgraded my conference pass to a full pass, which is cool as I get to attend sessions! And the kind ladies of ODTUG had even attached an ACE Associate ribbon to my name-tag, of which I am kind of proud.

I had so many cool meet-ups and run-ins at Kscope. Just to name a few new friends in no particular order:

Of course I spent most of my time in the APEX and database development tracks. If you look at the momentum that APEX is generating, I think we can safely say that we are making a difference… We can say with confidence: #LetsWreckThisTogether!

The “together” bit was beautifully expressed by Joel Kallman as you could hear a pin drop when Carl Backstrom and Scott Spadafore of the APEX team were remembered…

But still there is a lot of work that has to be done to further spread the word on APEX. I guess I have had at least 4 conversations where I had the opportunity to talk about and explain APEX to people who were still oblivious. That is one of the most rewarding this to do.

Nikki beachThe week passed so quickly and most experiences are becoming great memories very quickly now. The countless meet ups with friend and heroes from the Oracle world, the white party at Nikki Beach and the after party at The Mansion and of course the Oracle content which was dished out with great quality.

Just on more thing… Travelling Über is the best! I have been doing this in San Francisco and used the service here to get back to the airport. Why would you take a taxi with this service around? Because of the way it works, the drivers I have met, have been much more friendly than regular ‘cabbies’. I would recommend this any day.

So, now I am heading home, hanging in the sky somewhere between Fort Lauderdale and Atlanta. Thinking back on Roel’s blog post on his first Kscope… will this have changed my life? Quite possibly, but on the other hand things could not get much more crazy than they have been over the last 6 to 12 months!!

If you are looking to read up on the business side of things, please check out the FOEX blog!

Please also don’t forget to check out the #Kscope15 hash tag on Twitter and remember, when you are at an Oracle conference, also use the #orclconf as additional hash tag. This will help to make it even easier to follow your favorite tech-community on-line!

Using a terminal emulator on Mac

Dumb title for a blog post? No, not really I guess…

ZOC Terminal emulatorI have been using a terminal emulator, basically ever since I got away from the VT100 terminal:

  • ICE.TCP Pro
  • KEAVT
  • Reflection ‘X’

And a few other obscure applications that I cannot even recall anymore.
Currently, and over the last 6 to 8 years, I have been using ZOC.

The background of this story is: In the beginning these were the first DOS PC’s and later some Windows based machines that needed to interface with (in my case) VAX VMS, and later with the other UNIXes.

But why use a terminal emulator on MAC, for crying out loud? I hear you think… OS X is a Unix, so it should be all native, right?
Wrong! Well, kind of…

There are so many small (and bigger) differences when using various systems that it pays off to have a program that allows you to tune into these differences. Nothing more annoying than a backspace key that does not work or key-combinations that act different than you would expect.
This is even more true when you work with a mix of different operating systems, Solaris, HP UX, Oracle Linux, perhaps even some IBM OS’s.
And for when you would like to have further tune-ability of you toolkit, ranging from colors, to sizes, from fonts to layout.  Frivolities? Perhaps, but if you spent a lot of your time everyday in such a  tool, it does make a difference.

Printer terminal, also a terminal emulatorMore importantly are configurable logging, for documentation and troubleshooting. You can regard this as the modern variation to the old school print terminal (who can remember those?)
Configuring transfer types, modem and commutation settings and keeping these organized. As well as password storage and administrative support.

Well, basically, this is why I use a terminal emulator on my MAC!
And I think I found a valid tool in ZOC, by Markus Schmidt. Please check it out ZOC

Well, I hope you get to enjoy your terminal work as much as I do!

Register redo-log manually with Divisit Replicate

For those of you who haven’t been working with on-line data replication; in short, it is a way to copy data from a source database to a target database and do this on-line (both databases are active) and do it near-real-time.
This means that when you enter data in you source database, you can immediately query it from your target database. This makes on-line data replication ideal for numerous tasks, like moving and / or upgrading your database while it is being used, with almost no downtime at all.

This tale is of an actual project that I conducted. I used Dbvisit Replicate as my tool of choice.

dbvisit-replicate-logical-replication-made-easy-18-638Dbvisit Replicate can use a so-called FETCHER process to act as the “long-arm” for the MINE process. Mining extracts the information from the redo-log files, but, in specific situations, this can be too much of an overhead for the source database server. By moving the MINE to a proxy server, this overhead can be significantly reduced.

In some cases it can be useful to manually transfer redo-log files to the mining stage directory of Dbvisit.
I came across this requirement when catching up a lot of redo from a RAC database. In this case, the RAC cluster creates two streams of redo. When starting the replication processes, the first thread is transferred by FETCHER from the source server to the proxy, before the second thread is transferred. This means mining will pause until the second thread successful delivers the first redo-log file of the second thread. The redo-log information from the second stream is necessary to create consistent and chronologically ordered SQL-statements for the target database. In effect, the SCN’s from first redo-log information of the first stream need to line up with the SCN’s of the second redo-log information.

In this case, this meant having to wait a day or more before mining can start. This is why I decided to copy a number of redo-log files from the source server to the proxy server, where the MINE process is running, manually.
After the copy, the files need to be registered with in the dbvrep-repository. Without this information, the MINE process has no knowledge of the files that are present and about what their contents are.

The update is an easy insert statement, but it should be handled with care, as this needs to be quite precise and it needs a bit of specific information about the redo-log files being added.
You can use the following insert statement to register the files:

insert into dbvrp.dbrsmine_redo_log_history
       (
       ddc_id
     , mine_process_name
     , sequence
     , thread
     , resetlogs_id
     , first_scn
     , next_scn
     , online_name
     , arch_name
     , read_count
     , from_fetcher
     , last_mine_start
     , last_mine_end
     , create_date
     , last_change_date
       )
values
       (
       1
     , ‘MINE’
     , 128779 -- sequence number of the copied file;
     , 2 -- assuming you are updating this thread.
     , 804864915 -- the reset-logs id from the redo-log file
     , 199910296688 -- the first scn from the redo-log file
     , 199911476897 -- the next scn from the redo-log file
     , null
     , ‘/u01/app/oracle/some-big-storage/dbvrep-mine/mine-stage/thread_2_seq_128719.1485.804864915’
       -- full path and name of the file
     , 0
     , ‘Y'
     , null
     , null
     , sysdate
     , sysdate
       )
;

And you can get the information you need about the files here:

select lh.sequence#
     , di.resetlogs_id
     , lh.first_change#
     , lh.next_change#
  from v$log_history lh
 inner join v$database_incarnation di
 using (resetlogs_change#)
 where sequence# = 128779
;

After registering the first file for the second thread, in the Replicate-console, you can watch the MINE process kick off. This process will then again halt after the first file of the second stream is processed in parallel with the first file of the first stream.

Schermafbeelding 2015-05-31 om 21.23.11

I kept adding files until the FETCHER process was able to take over, or you could do this until you test-case or PoC is over.