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Applying Block Sampling When Statistics Collection Is Delayed

Document Type | Troubleshooting

Category | Monitoring/Inspection

Applicable Product Version | 6FS07

Document Number | TMOTS024

 

Issue

Due to delays in statistics collection, the collection process continues, causing an impact on the service. 
 
 
 

Cause

As data volume increases, the time required to collect statistical information lengthens, resulting in the collection process continuing throughout business hours. 

 

 

Solutions

Apply the patch to resolve the issue. (Applied Patch: 191464)
  • It is ideal to schedule the statistics collection time according to the service characteristics; however, if unavoidable, consider applying the block sampling method to shorten the statistics collection time.
Caution
Apply the patch through technical support provided by Tmax TIBERO.
 
Note
  • Block Sampling: Sampling is performed in block units; while the accuracy of the sample size is lower, the collection speed is faster.
  • Row Sampling: Sampling is performed in row units; while the sample size accuracy is higher, the collection speed is comparatively slower.
=> Block sampling retrieves blocks without exploring inside each block, so accuracy is lower but time is reduced. Therefore, it can shorten the time when sampling large tables.
 
 
 
 
 

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