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Let us finally focus on my problem.I will come back to my query : As a reminder – the predicates which are of the greatest importance are the following : The state before tuning If not timed out after 2 minutes (such constraint was applied at the application layer) with the SQL Plan depicted below…
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After this rather long discussion of what led the optimizer to choose one index over another — and, more importantly, of the significant consequences this choice brought — let us return to my test query.Bad news though – we are still not done with the optimizer’s internal decision-making, so this means diving yet again into…
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A time ago I stumbled upon a multi-dimensional performance problem where the OEM sessions got completely stuck spawning a growing pile of SQL executions that felt practically never-ending.The culprit was a standard OEM query that returns genuinely useful information (you’ll recognize it immediately from the SQL text): tablespace space utilization, temp tablespace details, and related…
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This post continues from :”When OEM meets the CBO: cardinality chaos across containers – Part 1“ Getting down to a single & simple query and using “FROM CONTAINERS” to my own advantage Let’s further “divide and conquer” –to confirm that each component of the “UNION ALL” being executed at the CDB level (which looks like that…
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Latest posts
- Be cautious when the optimizer estimates a cardinality of 1 – Part2
- Be cautious when the optimizer estimates a cardinality of 1 – Part1
- Be cautious when the optimizer estimates a cardinality of 1 – Part3
- When OEM meets the CBO: cardinality chaos across containers – Part 1
- When OEM meets the CBO: cardinality chaos across containers – Part 2
- Auto SQL Plan Management (look under the hood) – part 1
- Auto SQL Plan Management (look under the hood) – part 3
- Auto SQL Plan Management (look under the hood) – part 2
- Converting of CPU Costing in the Cost Based Optimizer 10053 Trace File
- Why this extra physical read while performing index scan?