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Category Archives: Uncategorized
Scripts to collect, truncate Exadata state dumps
I’m still doing state dumps as described in my previous post. I wanted to collect the state dumps (diag process trace files) from all nodes of my Exadata database and decided to write a couple of scripts to automate it … Continue reading
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oradebug -g all dumps to diag process trace file
One of my favorite children’s books when my children were younger was one about the Berenstain Bears where Father Bear tries to teach his son how to ride a bike and keeps making all these dumb mistakes. “Let that be … Continue reading
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_unnest_subquery=FALSE for PeopleSoft performance?
Oracle support recommends setting the hidden parameter _unnest_subquery to FALSE to improve the performance of PeopleSoft applications on Oracle databases. I’m trying to understand the consequence of changing this parameter from its default setting of TRUE. PeopleSoft applications have a … Continue reading
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SET AUTOTRACE TRACEONLY to test effect of patch
In an earlier post I described the process that I go through to check the plans of production SQL queries to see if they change when you do a system upgrade or patch. Today I’ve been following that process to … Continue reading
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Global index faster than local in some cases
We usually use locally partitioned indexes on partitioned tables. Many of our data warehouse tables are partitioned by date and partitions get added or removed over time. It is much easier to maintain the indexes on this kind of table … Continue reading
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Script to get AWR previous day, week, month
I’ve uploaded a sql script that gets an AWR report for yesterday, a week from yesterday, and four weeks from yesterday for the same time period – 10 am to 4 pm. I’ve been manually reviewing the previous day’s AWR … Continue reading
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Good chapter for V$ views and AWR report
I’m helping a coworker learn how to do Oracle performance tuning and today I think we found some good documentation on which V$ views to use for tuning which can also help with reading an AWR report. In a previous … Continue reading
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Compression preserved on inserts with append hint
I’ve known for a while that if you have an Exadata table compressed with Query High compression and you want to load data into it and have it be compressed as it is loading you have to use direct path … Continue reading
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APPEND_VALUES hint
A coworker of mine just brought a new hint to my attention – the APPEND_VALUES hint. I’m used to the append hint which makes insert statements use direct path instead of conventional loading. Here is what the old standby append … Continue reading
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Cardinality the heart of SQL tuning
I’m at the East Coast Oracle Users Conference and wanted to write a blog post about the first day, which is now done. Rather than summarize all the sessions I thought I would focus on what struck me the most … Continue reading
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