Forum Post: Re: Performance Degradation After Dump&load

  • Thread starter Thread starter George Potemkin
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George Potemkin

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> Where do you see scanning of 2 phases? Example, for sports db: Scanning .\sports_8.d1 From dbkey 32 to dbkey 2528 Scan of Customer/Order Area extent 1 10% complete Scan of Customer/Order Area extent 1 20% complete Scan of Customer/Order Area extent 1 30% complete Scan of Customer/Order Area extent 1 41% complete Scan of Customer/Order Area extent 1 50% complete Scan of Customer/Order Area extent 1 60% complete Scan of Customer/Order Area extent 1 70% complete Scan of Customer/Order Area extent 1 80% complete Scan of Customer/Order Area extent 1 91% complete Scan of Customer/Order Area extent 1 100% complete Rebuilt RM chain with 0 blocks on object 0/8. Rebuilt RM chain with 0 blocks on object 2/1. Rebuilt RM chain with 0 blocks on object 16/2. Rebuilt RM chain with 0 blocks on object 4/1. Rebuilt RM chain with 0 blocks on object 21/2. Rebuilt RM chain with 0 blocks on object 5/1. Also I did timing on large db with partition enabled. Rebuild of RM chains with 1000 blocks ("Rebuilt RM chain" phase) may take a few minutes. If we answer Yes to the question: "Scan Backward (Yes/No)?" then the scan is very slow (5-6 hours for 20 GB area) and the result is funny: blocks on RM chains will be sorted in the descending order by the clusters but in the ascending order by dbkey inside each cluster. If the answer is No then the scan is going much (many times) faster and the chains will be rebuilt in right order.

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