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December 2012

Debra Lilley’s email disclaimer…

I think I’m going to reply to all of Debra Lilley‘s emails with my own disclaimer that says,

Unless otherwise stated, this email has got nothing to do with Debra Lilley or the massive disclaimer that gets added to every email she sends… Even the iddy-biddy 3 word emails…

That Fujitsu email disclaimer is one serious piece of text!

Heaven forbid you get an out of office reply… :)

Cheers

Tim…

Storage Indexes vs Database Indexes Part II: Clustering Factor (Fast Track)

Two posts in two days !! Well, with Christmas just around the corner, I thought I better finish off a couple of blog posts before I get fully immersed in the festive season The Clustering Factor (CF) is the most important index related statistic, with the efficiency of an index performing multi-row range scans very much […]

Some stuff about dates and timestamps in Oracle

set null ~ pagesize 40 linesize 132;
column id format 90;
column datetrunc format a30;
column dateuntrunc format a30;
column timetrunc format a30;
column timeuntrunc format a30;
create table time_size2
(
id number,
datetrunc date,
dateuntrunc date,
timetrunc timestamp,
timeuntrunc timestamp
);
insert into time_size2
select rownum, trunc(sysdate), sysdate,trunc(sysdate),sysdate
from dual;
insert into time_size2 values (2,null,null,null,null);
commit;
select * from time_size2;
select
to_char(datetrunc, 'YYYY MM DD HH24:MI:SS') "datetrunc",
to_char(dateuntrunc,'YYYY MM DD HH24:MI:SS') "dateuntrunc",
to_char(timetrunc, 'YYYY MM DD HH24:MI:SS.FF9') "timetrunc",
to_char(timeuntrunc,'YYYY MM DD HH24:MI:SS.FF9') "timeuntrunc"
from
time_size2;

Snapper v3.61 released – and more work is in progress!

Here’s the latest version of my Oracle session level performance Snapper tool:
https://github.com/tanelpoder/tpt-oracle/blob/master/snapper.sql I’m going to add more stuff to Snapper in coming days, but thought to release something for testing already :)
There are some cosmetic changes, like printing empty lines and header lines for better readability (still controllable by the pagesize parameter, look into the scripts). I’ve made some changes in the visual “graph” column just for easier readability when glancing at a snapper report: the @-character is used for CPU time (@ looks like a letter C a bit, doesn’t it :)

Snapper v3.61 released – and more work is in progress!

Here’s the latest version of my Oracle session level performance Snapper tool:
https://github.com/tanelpoder/tpt-oracle/blob/master/snapper.sql I’m going to add more stuff to Snapper in coming days, but thought to release something for testing already :)
There are some cosmetic changes, like printing empty lines and header lines for better readability (still controllable by the pagesize parameter, look into the scripts). I’ve made some changes in the visual “graph” column just for easier readability when glancing at a snapper report: the @-character is used for CPU time (@ looks like a letter C a bit, doesn’t it :)

Snapper v3.61 released – and more work is in progress!

Here’s the latest version of my Oracle session level performance Snapper tool:

I’m going to add more stuff to Snapper in coming days, but thought to release something for testing already :)

Database Virtualization

What is database virtualization? Database virtualization, as opposed to operating system virtualization, is sharing a read only copy of a source database between clone databases. The clone databases are called virtual databases (also called thin provision clones as distinct from full physical copy clones).  Virtual databases are much more than simple read only databases. The virtual databases can also write to the data files. How can the virtual databases write to the data file when the data files are read only? Writing to the data files is accomplished either through one of two basic mechanisms. Those mechanisms are block pointer copy on write file systems or journal file systems. When a virtual database writes to the data files the changes are not written to the data file but are kept in a private area only visible to that virtual database. Each virtualized database sees what appears to be a private read/write copy of the database.

Who Stole gettimeofday() System Calls From Oracle strace() sessions?

I’ve been meaning to write this blog post for a while now but never seemed to find the time. Hopefully this posting will be useful information for anyone that spends a lot of time tracing processes in Oracle from the Linux Operating System. I’m one of those people, so it was good to get to … Continue reading "Who Stole gettimeofday() System Calls From Oracle strace() sessions?"

Who Stole gettimeofday() System Calls From Oracle strace() sessions?

I’ve been meaning to write this blog post for a while now but never seemed to find the time. Hopefully this posting will be useful information for anyone that spends a lot of time tracing processes in Oracle from the Linux Operating System. I’m one of those people, so it was good to get to … Continue reading "Who Stole gettimeofday() System Calls From Oracle strace() sessions?"

Who Stole gettimeofday() System Calls From Oracle strace() sessions?

I’ve been meaning to write this blog post for a while now but never seemed to find the time. Hopefully this posting will be useful information for anyone that spends a lot of time tracing processes in Oracle from the Linux Operating System. I’m one of those people, so it was good to get to … Continue reading "Who Stole gettimeofday() System Calls From Oracle strace() sessions?"