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www.dbaglobe.com | ||
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oracle-randolf.blogspot.com
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| | | | | When attempting to display only the first n rows of a result set that is ordered the Oracle optimizer offers special optimizations for these... | |
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blog.tanelpoder.com
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| | | | | Hello all fellow Oracle geeks and technology enthusiasts! Long time no see ;-) In the hacking session about Oracle full table scans and direct path reads I explained how the direct path read decision is not done by the optimizer, but instead during every execution, separately for every single segment (partition) scanned in the query. I also explained how the _small_table_thresholdparameter and theX$KCBOQH.NUM_BUF(which keeps track of how many buffers of any segment are currently cached) are used for determining whether to scan using direct path reads or not. - Linux, Oracle, SQL performance tuning and troubleshooting training & writing. | |
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orastory.wordpress.com
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| | | | | There have been some interesting posts from Marcin Przepiorowski and Kerry Osborne about mapping sql plan management (spm) baselines to a corresponding sql id. The key to sql plan baselines (DBA_SQL_PLAN_BASELINES) is SIGNATURE. And why signature? It's not just another change to the key to identifying sql statements (HASH_VALUE -> (NEW_)HASH_VALUE / OLD_HASH_VALUE -> SQL_ID).... | |
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hourim.wordpress.com
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| | | I like very much Tanel Poder snapper and Carlos Sierra SQLTXPLAIN. They represent valuable performance diagnostic tools. Unfortunately I am still waiting to find a customer site where I will be allowed or granted necessary privileges to install and to use them. There are client sites where I have been asked to tune queries without... | ||