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ORA-01722: upgrade error
I received an email recently from someone who had just upgraded the Oracle 11i Business Suite (11.5.9) from 9.2.0.6 to 10.2.0.2. After the upgrade, the following SQL statement (shown here with its...
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System Statistics
In chaper 2 of Cost Based Oracle – Fundamentals, I made the following comment about system statistics. “… you could simply calibrate your hardware (or at least the I/O subsystem) for absolute...
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System Stats strategy
A few days ago I received an email about system statistics. I decided it was worth replying to, provided I wrote my response up as a series of questions and answers on the blog. (I don’t tend to...
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System Statistics 3
In a recent thread on one of the Oracle Forums, someone asked the question: So, in general, if systems statistics are in effect, would you or would you not make any adjustments to the...
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System Statistics
I wrote an article about system statistics / CPU Costing for Oracle magazine a few years ago – and last week I realised that I’ve never supplied a link to it in the notes and comments I’ve made about...
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System Stats
A quick collation – and warning – for 11.2 MOS (Metalink): Bug 9842771 - Wrong SREADTIM and MREADTIM statistics in AUX_STATS$ [ID 9842771.8] (needs MOS account) Comment from Sokrates in a Charles...
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System Stats
Several years ago I wrote the following in “Cost Based Oracle – Fundamentals” (p.47): The maxthr and slavethr figures relate to throughput for parallel execution slaves. I believe that the figures...
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maxthr – 2
Actually, there hasn’t been a “maxthr – 1″, I called the first part of this series“System Stats”. If you look back at it you’ll see that I set up some system statistics, excluding the maxthr and...
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maxthr – 3
In part 1 of this mini-series we looked at the effects of costing a tablescan serially and then parallel when the maxthr and slavethr statistics had not been set. In part 2 we looked at the effect of...
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sreadtim
Here’s a question that appeared in my email a few days ago: Based on the formula: “sreadtim = ioseektim + db_block_size/iotrfrspeed” sreadtim should always bigger than ioseektim. But I just did a...
View Articlegather_system_stats
What happens when you execute dbms_stats.gather_system_stats() with the ‘Exadata’ option ? Here’s what my system stats look like (12.2.0.1 test results) after doing so. (The code to generate the two...
View Articlesystem_stats() hint
Starting from 18.3 Oracle introduced the system_stats() hint, apparently allowing you to set the system statistics for the duration of a query. However the hint didn’t seem to have any effect in that...
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