Infrastructure at your Service

All posts by Clemens Bleile

Clemens Bleile
Senior Consultant

Clemens Bleile has more than 24 years of IT experience, thirteen in Oracle Support and eight in Oracle Consulting. He is specialized in Oracle Database Performance Tuning (SQL Tuning, DB Tuning) and developing an Oracle DB IT architecture (highly available, low-maintenance, cost efficient storage of data). He is an expert in problem analysis and resolution. Prior to joining dbi services, Clemens Bleile was Manager of the EMEA Database Performance team at the Oracle Global Customer Support Services. Clemens Bleile is Oracle Certified Professional 11g, 12c and Oracle Certified Expert for Performance Management and Tuning and holds a Master Degree, Business Information Systems from the Fachhochschule Furtwangen, Germany.
Clemens Bleile

DOAG 2017: avg_row_len with virtual columns

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

At the DOAG I attended a session “Top-level DB design for Big Data in ATLAS Experiment at CERN” provided by Gancho Dimitrov. The presentation was actually very interesting. As part of Gancho’s improvement activities to reduce space in a table he stored data in a 16 Bytes raw format (instead of a string representing hex values which requires 36 Bytes) and use virtual columns to actually calculate the real hex-string. So the original value is…

 
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Clemens Bleile

Recommended DB Parameters on the Oracle Database Appliance (ODA)

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

When creating a DB on the ODA using # oakcli create database -db <db-name> a template is used to set a couple of DB parameters like e.g. _datafile_write_errors_crash_instance=FALSE _db_writer_coalesce_area_size=16777216 _disable_interface_checking=TRUE _ENABLE_NUMA_SUPPORT=FALSE _FILE_SIZE_INCREASE_INCREMENT=2143289344 _gc_policy_time=0 _gc_undo_affinity=FALSE db_block_checking=’FULL’ db_block_checksum=’FULL’ db_lost_write_protect=’TYPICAL’ filesystemio_options=’setall’ parallel_adaptive_multi_user=FALSE parallel_execution_message_size=16384 parallel_threads_per_cpu=2 use_large_pages=’ONLY’ In recent projects I saw a couple of DBs running on ODA, which did not have (all) those parameters set, because the DBs were migrated from a non-ODA-platform and the customer took over…

 
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Clemens Bleile

Workaround for bug 19566227/20563128 doing Cross Platform Migration (MOS Note 1389592.1)

By | Database Administration & Monitoring, Database management | One Comment

In a project I have to move an Oracle 11.2.0.4-DB (around 7TB in size) from Sparc Solaris (called Source in the remainder of this Blog) to Linux x86-64 (called Target in the remainder of the Blog). I.e. a platform migration from Big Endian to Little Endian. A good method to do that is described in My Oracle Support Note 1389592.1: 11G – Reduce Transportable Tablespace Downtime using Cross Platform Incremental Backup Basically I copy the…

 
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Clemens Bleile

Trace files segmented in multiple parts as a workaround for bug 23300142

By | Database Administration & Monitoring | No Comments

Today I visited a customer, who deleted a Data Guard configuration (i.e. a temporary Data Guard setup through the broker was deleted). The LOG_ARCHIVE_DEST_STATE_2 on the primary database was set to DEFER temporarily. That resulted in trace-files with name *tt*.trc to become huge (GBytes after a couple of days). Analysis showed that this was caused by bug 23300142 in 12.1.0.2. See My Oracle Support Note Bug 23300142 – TT background process trace file message: async…

 
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Clemens Bleile

SQL Plan Directives in 12cR2. Behavior is different than in 12cR1.

By | Database Administration & Monitoring, Database management | 10 Comments

During the Frankfurter IT Tage I provided a presentation about SQL Plan Directives and how to reproduce a testcase in a test environment for a plan with used SQL Plan Directives (SPD). In that context I did a couple of tests with 12cR2 (12.2.0.1) and wanted to blog about the change in behavior in that release. Here is my testcase I did initially run in 12.1.0.2: First I created a table with 4 columns: A,…

 
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Clemens Bleile

OTN Appreciation Day : External tables

By | Database Administration & Monitoring | No Comments

As part of the OTN Appreciation Day (see https://oracle-base.com/blog/2016/09/28/otn-appreciation-day/) I’m writing about one of my favorite Oracle features: External tables. Traditionally people loaded data in an Oracle database using SQL*Loader. With the introduction of external tables, SQL*Loader became obsolete (in my view ;-)), because external tables provide the same loading capabilities and so much more than SQL*loader. Why? Because external tables can be accessed through SQL. You have all possibilities SQL-queries offer. Prallelism, difficult joins…

 
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Clemens Bleile

Oracle Open World 2016 – Day 4 and 5

By | Database Administration & Monitoring | No Comments

At the end of Oracle Open World my last BLOG concerning OOW 2016 covering day 4 and 5: Wednesday is the day of the Party: Oracle’s appreciation event, a concert with Gwen Stefani and Sting at the AT&T Park (Stadium of the San Francisco Baseball team, the Giants). It was a great event with awesome musicians. Before the party I visited the session “Oracle Active Data Guard: Power, Speed, Ease and Protection” provided by Larry…

 
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Clemens Bleile

Oracle Open World 2016 – Day 3

By | Database Administration & Monitoring | 2 Comments

On day 3 I visited various sessions about In-Memory and its many new features in 12gR2. Yesterday I already listed some new features of In-Memory. In this post I want to explain the new features more in detail:   In-Memory Join Groups: Columns are specified, which are used to join tables: CREATE INMEMORY JOIN GROUP V_name_jg (VEHICLES(NAME), SALES(NAME)); Those columns share the compression dictionary. My understanding on how this works is as follows: The joins…

 
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Clemens Bleile

Oracle Open World 2016 – Day 2

By | Database Administration & Monitoring | One Comment

Day 2 is the first official day of the Oracle Open World (OOW) 2016. As a parallel event the Oak Table Network organized his Oak Table World (OTW) close to the Open World. I attended several sessions from OOW and OTW: Jeremy Schneider: Ansible Ansible is a very light software written in Python, which allows automation in deploying applications and managing systems. The main goal of the developer of Ansible Michael DeHaan was to make…

 
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Clemens Bleile

Oracle Open World 2016 – Day 1

By | Database Administration & Monitoring | No Comments

Oracle Open World 2016 started on Sunday. The first day is always reserved for presentations provided by members of the various Oracle User Groups. However, the last part of the day is the first Keynote from Larry Elison. But let’s start by some of the sessions I visited Sunday: Ludovica Caldara: Migrating to Oracle Databases 12c: 300 databases in 300 days. Ludovica provided a presentation about the experience he gained during the migration project of…

 
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