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Franck Pachot

Covering indexes in Oracle, and branch size

By | Oracle | No Comments

A covering index is an index that contains all the columns required by your query, so that you don’t have to do a TABLE ACCESS BY INDEX ROWID, which is the major cost of an index range scan. You don’t need any special feature to do that in Oracle. Just add the required columns at the end of the index. In the execution plan you will see the columns used as index keys for the…

 
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Marc Wagner

Dbvisit Standby Archive Log Daemon

By | Database Administration & Monitoring, Oracle | No Comments

Dbvisit Standby version 8 comes with a nice feature, a daemon, which gives the benefit to send and apply the archive log automatically in the background. Bypassing the system scheduling, the daemon will facilitate customer RPO (Recovery Point Objective) and RTO (Recovery Time Objective) fine tuning. Monitoring to apply logs to the Standby only when needed, will also optimize use of resources. Originally available for the Linux based environments, the feature has been made available…

 
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Clemens Bleile

sqlplus and its column output

By | Database Administration & Monitoring, Database management | No Comments

During tuning or normal DBA activities one of the most annoying things is sqlplus with its default column output when running queries. I.e. even after setting a linesize of 1000 and a pagesize of 1000 the output may look as follows in your preferred terminal emulation (putty here): Most people address this by using other tools like sqldeveloper (or sqlcl with sqlformat ansiconsole). However, a lot of people still use sqlplus. How can you address…

 
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Franck Pachot

Docker: efficiently building images for large software

By | Oracle | No Comments

I see increasing demand to build a Docker image for the Oracle Database. But the installation process for Oracle does not really fit the Docker way to install by layers: you need to unzip the distribution, install from it to the Oracle Home, remove the things that are not needed, strop the binaries,… Before addressing those specific issues, here are the little tests I’ve done to show how the build layers increase the size of…

 
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Jérôme Dubar

How reimaging detects the ODA hardware?

By | Database Administration & Monitoring | No Comments

A long time ago, ODA referred to the only model that existed (nearly). Actually, not so long time ago, as ODA X3, X4 and X5 were released between 2013 and 2015. And it was quite the same hardware. Now there is 3 current models in the X7 range, and they were 4 in the previous generation (X6). ODA is now divided in 2 main lines. High Availability models, understand 2 nodes and a shared storage…

 
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Franck Pachot

Result cache invalidation caused by DML locks

By | Oracle | No Comments

In a previous post about Result Cache, I was using ‘set autotrace on’ in my session to see when the result cache hit saves the logical reads. I got a comment, by e-mail and with full test case, mentioning that the invalidation I had when doing some DML does not occur when autotrace is set to off. I reproduced the problem, on 18c because I use my cloud services to do my tests, but it…

 
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Clemens Bleile

Connect-times to the DB suddenly become very slow using sqlcl

By | Database Administration & Monitoring, Database management, Development & Performance, Oracle | 2 Comments

I recently wrote a couple of sql-scripts which had to run on all of my customer’s DBs. The sql-scripts had to be started from a Linux-client, which does not have any Oracle client software installed. So I thought of using sqlcl (see http://www.oracle.com/technetwork/developer-tools/sqlcl/downloads/index.html), because there is no need to “install” something then. All I needed was an installed JRE on the Linux-machine. Fortunately that was available. So I downloaded the newest version of sqlcl and…

 
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David Hueber

ODA migration challenges: Non-OMF to OMF + 11.2.0.3 to 11.2.0.4

By | Database Administration & Monitoring | One Comment

To do some application and performances tests, I had to copy a database from a third party Linux server to an ODA X7-2M. Looks pretty simple on the paper, but 2 small challenges came into the game. The first was that of course the source database was in Non-OMF while ODA works fully in OMF. The second was that the source database is running 11.2.0.3 which is not supported and cannot be installed on the…

 
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Pierre Sicot

ORA-12547 TNS lost contact on SLES12 and oracle 11.2.0.x

By | Database Administration & Monitoring | No Comments

On a client’s site, I have migrated successfully Oracle 12c databases from RedHat to SLES12 without any problem. I encountered a problem doing the same work with Oracle 11.2.0.3 and oracle 11.2.0.4 on SLES 12. Once I have moved the database data files, redo logs, control files and spfile to the new server, when I try to startup the database, I receive the error message: oracle@server:/u00/app/oracle/diag/ [db1] sq SQL*Plus: Release 11.2.0.3.0 Production on Thu Feb…

 
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