How much free space can be reclaimed from a segment?
You have the feeling that your table takes more blocks than it should? Here are the queries I use to quickly check the free space. The idea is to call DBMS_SPACE.SPACE_USAGE and infer the minimum space...
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MERGE JOIN CARTESIAN: a join method or a join type?
I’ll present about join methods at POUG and DOAG. I’ll show how the different join methods work in order to better understand them. The idea is to show Nested Loops, Hash Join, Sort Merge Join, Merge...
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ATP vs ADW – the Autonomous Database lockdown profiles
The Oracle database has always distinguished two types of workloads: transactional (OLTP) and datawarehouse (VLDB, DWH, DSS, BI, analytics). There is the same idea in the managed Oracle Cloud with two...
View ArticleTRANSPORT_CONNECT_TIMEOUT and RETRY_COUNT
When you have a Data Guard configuration, you want the application to connect to the right server, where the primary is, without taking too much time. The default TCP timeout is 1 minute which is too...
View Article18c runInstaller -silent
You find two different ‘runInstaller’ under an Oracle Home. The old one, the Oracle Universal Installer, in $ORACLE_HOME/oui/bin. And the new one, in $ORACLE_HOME directly. They have the same name but...
View ArticleORACLE_HOME with symbolic link and postupgrade_fixups
Here is a quick post you may google into if you got the following error when running postupgrade_fixups.sql after an upgrade: ERROR - Cannot open the preupgrade_messages.properties file from the...
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Oracle Database on OpenShift
By Franck Pachot . In a previous post I described the setup of MiniShift on my laptop in order to run OpenShift for test purpose. I even pulled the Oracle Database image from the Docker Store. But the...
View ArticleThe size of Oracle Home: from 9GB to 600MB
This is research only and totally unsupported. When building docker images to run Oracle Database in a container, we try to get the smallest image possible. One way is to remove some subdirectories...
View ArticleA tribute to Natural Join
By Franck Pachot . I know that lot of people are against the ANSI join syntax in Oracle. And this goes beyond the limits when talking about NATURAL JOIN. But I like them and use them quite often. Why...
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strace the current Oracle session process
Here is my way to trace system calls from the current session process. This must not be done in production.An strace.log file will be generated with system callsconnect / as sysdbacolumn spid new_value...
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Oracle archivelog deletion policy
Here are my posts on the dbi-services blog about archivelog deletion policy.The deletion policy on a dataguard configuration should be: CONFIGURE ARCHIVELOG DELETION POLICY TO APPLIED ON ALL...
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Stays One Step Ahead With Certification
I started with Oracle certifications at the time of 8i. I had good experience on development side, but more limited on operation side. The certification, 4 exams at that time, was the way for me to...
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Oracle: connection rate to the listener
A single line command to read the listener log, filter the message from a date (you can change it), and group by hour to count the connections:adrci exec='set home diag/tnslsnr ; show alert -term -p...
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Installing ZFS on OEL7 UEK4
Here are the commands I use to setup ZFS on Oracle Linux#This was tested on OEL 7.2 in Oracle Cloud Compute Classic and OEL 7.5 in Oracle Cloud infrastructureset -xcat /etc/oracle-releaseyum -y install...
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Conferences 2018
Here are the conferences where I speak this end of yearJoin Methods: Nested Loop, Hash, Sort, Merge, AdaptiveThis is an explanation of the join methods, with live demos on very simple cases, reading...
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Download your SR content from MOS
You may want to keep track of your Oracle Service Requests offline. Or simply be able to read them as simple text. Here is a simple way to download all of them to a simple text file.First, it is easy...
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ASM Filter Driver — simple test on filtering
Here is a simple test on ASM Filter Driver showing that when filtering is enabled the disks presented to ASM are protected from external writes.On a 12.2 Grid Infrastructure installation I have my...
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Recursive queries on IM_DOMAIN$ at each cursor execution
At POUG 2018 conference I explained join methods by putting gdb breakpoints on the qer (Query Execution Rowsource) functions that are behind the execution plan operations. I was a bit annoyed by...
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How to gather Oracle optimizer statistics with minimal risks of regression
Here is, on the Databases at CERN blog, an example to lower to risks when you need to gather statistics in production:use pending stats to be able to test them before publishingbe ready to restore old...
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Start/Stop your Autonomous Databases
The ATLAS experiment in LEGO®Here are two blog posts on the Databases at CERN blog:Oracle Cloud Infrastructure API Keys and OCIDOracle Cloud: start/stop automatically the Autonomous DatabasesThe idea...
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