A couple of weeks back I received an update on my “4k bug” SR (slow multirow DML performance for small block sizes). As it turns out, the observed behavior is not a bug. It’s actually more interesting than that. It is an undocumented feature that controls the insert mode depending on the estimated row size (the sum of all column sizes). If the estimated column size exceeds the size of the block, then Oracle switches to row-by-row processing.
Un billet en cette fin d'année qui approche à grand pas pour vous annoncer la sortie prochaine (fin décembre 2014) du livre SQL Server 2014 : Développer et administrer pour la performance en français et auquel j'ai eu l'immense plaisir de participer avec Frédéric Brouard (alias SQLPro - MVP SQL Server), Nicolas Souquet (alias Elsuket - MVP SQL Server) e
Purpose is to demonstrate how to create HA for Bi-Directional Replication Goldengate installed on ACFS with RAC cluster using XAG.
XAG simplifies the process since there are no requirements to create action scripts.
Please review REFERENCE section for versions used in test case and versions requirements.
Just a quick post to link to the slides from my presentation at the UKOUG Tech14 conference. The slides do not appear to be visible on the Super Sunday site, hence this post. The presentation was called “Testing Jumbo Frames for RAC”, the emphasis as much on the testing as on Jumbo Frames.
A discussion on the usage of Jumbo Frames for the RAC interconnect. We’ll cover background information and how this can be tested at the Oracle level and in the Operating system. We’ll also discuss how testing initially failed and why it’s interesting.
Jephe Wu - http://linuxtechres.blogspot.comObjective: undelete httpd access log file while httpd process is still runningEnvironment: CentOS 6.5 64bitCases Study:Sometime, you deleted a big httpd log file while httpd is still running. As long as httpd process doesn't exit, you still can recover removed deleted httpd log file.Apply to: Recover deleted file, data recovery under Linux, restore deleted file, undo deletionSteps:
I'll present here 3 ways to run a query for each result of another query. Let's take an exemple: get all executions plan (select from dbms_xplan.display_cursor) for each of my queries (identified from v$sql). The 90's way was to run the first query, which generates the second queries into a spool file, and execute that file. Here are easier ways, some of them coming from 12c new features lateral join and implicit statement result.
Jephe Wu - http://linuxtechres.blogspot.comEnvironment: CentOS 5.5 32bit web server with Apache httpd installed. We need to renew one of ssl certificate for our client.Objective: apply for new ssl cert without shutting down server
Anyone that has ever coded PLSQL will be familiar with the error ORA-4068, where you had some state persisted in a session due to a package variable, and then when you change the package, the state is cleared along with an ORA-4068. Here’s a quick example:
Hi, welcome to RDX! Using SUSE Linux Enterprise Server to manage your workstations, servers and mainframes? SUSE recently released a few updates to the solution, dubbed Linux Enterprise Server 12, that professionals should take note of.
For one thing, SUSE addressed the problem with Unix’s GNU Bourne Again Shell, also known as the “Shellshock” bug. This is a key fix, as it disallows hackers from placing malicious code onto servers through remote computers.