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5 Databases issues that are costing you time and money

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Companies rely on applications to supply the information that business uses to make decisions that generate revenue.

How to get dreadful database performance

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I love this video on “getting dreadful database performance” by Stephane Faroult.
The video is hilarious and informative:

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SQL*Plus Procedures and Password Encryption

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Sampling Performance Data on Oracle

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I want to be a simplifier – thanks Steve Jobs

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Any intelligent fool can make things bigger and more complex. It takes a touch of genius – and a lot of courage – to move in the opposite direction.

Why did Google succeed? Yahoo shuts altavista down

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Yahoo shut  #2970a6;" href="">Altavista down a couple of years ago. Why did Google succeed when Altavista had index the web before Google ever started?

Dan Rosensweig former COO at Yahoo responding to the question: Why did Google succeed in search over Yahoo?

Date conversions

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#555555;">Dates are a surprising pain for correlating data an at the same time being understandable to the human reader.

#555555;">For a generic form we can take seconds since 1970, on UNIX, with

#555555;">$ date '+%s'

#555555;">but then how to we convert it back? There is a neat trick for that, “date -d @”

#555555;">$ date -d @1311372938  +%H:%M:%S

#555555;">so in scripts we can load up the date into seconds, that can be subtracted to get deltas and at the same time converted easily to any date format :

I/O wait histograms in Oracle

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#555555;">DBA_HIST_EVENT_HISTOGRAM has a history of I/O latency histograms. DBA_HIST_EVENT_HISTOGRAM is only on 11g, so for 10g, it requires collecting the histogram deltas manually off of V$EVENT_HISTOGRAM, something like

set pagesize 150
col event format a25
col tm format a14
select event,
       to_char(sysdate,'J')||to_char(round(sysdate-trunc(sysdate),5)) tm,
from v$event_histogram
where event in ('log file parallel write' ,
                'db file scattered read' ,
                'db file sequential read' )
order by event;

#555555;">and collecting this information every N seconds and taking the deltas.

Version control a multi-terrabyte database?! Yes !

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Can you version control database?

How do you manage databases in application development?  For all the advances in application development such as machine virtualization , agile development, devops practices, the database still stands as a huge barrier to development agility.

NFS max “rsize” on Solaris – gotcha

Laptop and Stethoscope

#555555;">When mounting NFS file systems there is an option to set the max rsize requested. For example:

#555555;">mount -o rsize=1048576,wsize=1048576,proto=tcp,vers=3 /foo

#555555;">The general rsize used is 32K,  for example in Oracle documentation, but for large sequential I/O the larger rsize can make a big difference. In some tests the larger rsize was twice as fast.