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nenadnoveljic.com | ||
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www.bobbydurrettdba.com
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| | | | | We have been discussing query tuning at work and I've come back to an example of the Oracle optimizer choosing the wrong plan due to an error in its calculation of the number of rows returned... | |
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iusoltsev.wordpress.com
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| | | | | ??????? ?????? ?? ??????? ??????????? 465 ??????! SELECT A.ID, A.LOGIN, A.NAME, A.LASTNAME, A.EMAIL FROM ACCOUNT A WHERE (A.LOGIN LIKE '%%') AND (A.NAME LIKE '%????????%' OR A.LASTNAME LIKE '%????????%') AND A.COMPANY_ID = 1 ORDER BY A.LOGIN ??? ???????, ????????? ???? ?? ??????? A.COMPANY_ID = 1 ???????? ??????? ???????????????? SQL> SELECT 'ALL' as "Condition", count(*) FROM ACCOUNT... | |
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leonotes.wordpress.com
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| | | | | ????????transitive closure?Wiki??????????Oracle????????... | |
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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. | ||
