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optimizer_index_caching can affect unexpectedly results returned by query

edited Aug 19, 2017 5:02AM in SQL Performance (MOSC) 4 commentsAnswered

Hi,

Sometimes when tuned sql queries  (after collect statistics different ways, move tables and rebuild or create new indexes, etc.)  is necessary to adjust some knowledge optimize parameters like optimizer_index_caching, optimizer_index_cost_adj, optimizer_mode, optimizer_dynamic_sampling ,etc. and consequently get good results. Until today i practice this naturally without fear about get wrong results or non consistent values, when i use :

- optimizer_index_caching > 100 , no get result on query,  (wrong)

- optimizer_index_caching < 100 , get result on query. (correct)

Oracle version:   10.2.0.1, 11.2.0.3

S.O.: Oracle Linux

Someone has already experienced something similar, I looked for information in the documentation and support knowlegde (metalink) without success.

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