Found a total of 10000 related content
SQL Fragmentation Analysis and Resolution
Article Introduction：SQL fragmentation affects database performance and is mainly divided into internal fragments and external fragments. The detection method is to use the sys.dm_db_index_physical_stats function. The processing method selects reorganization or reconstruction according to the fragmentation rate. It is recommended to maintain it regularly to avoid performance degradation.
2025-07-29
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670
What is fragmentation in SQL indexes and how do you fix it?
Article Introduction：Index fragmentation refers to the inconsistent order of the indexes in SQLServer with the physical storage order or the unused space in the page, resulting in a degradation of query performance; it is divided into internal fragments (the page is not filled, adding I/O) and external fragments (the logic does not match the physical order, resulting in random read); indexes with fragmentation rate greater than 10% and page count exceeding 1000 can be detected through the sys.dm_db_index_physical_stats function; 1. There is no need to process the fragmentation rate below 10%; 2.10%-30% are used to organize online; 3. More than 30% are used to recreate the index using ALTERINDEXREBUILD to obtain the optimal structure; the best
2025-08-05
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774
How to deal with Redis memory fragmentation?
Article Introduction：Redis memory fragmentation refers to the existence of small free areas in the allocated memory that cannot be reassigned. Coping strategies include: Restart Redis: completely clear the memory, but interrupt service. Optimize data structures: Use a structure that is more suitable for Redis to reduce the number of memory allocations and releases. Adjust configuration parameters: Use the policy to eliminate the least recently used key-value pairs. Use persistence mechanism: Back up data regularly and restart Redis to clean up fragments. Monitor memory usage: Discover problems in a timely manner and take measures.
2025-04-10
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755
How does index fragmentation impact query performance, and how can it be addressed?
Article Introduction：Index fragmentation does affect query performance. Long-term accumulation will lead to slower queries, increased I/O load and decreased database response capabilities. They are mainly divided into internal fragments (many free space in the page) and external fragments (the pages are not continuous on disk). Detection can be done through the SQLServer's sys.dm_db_index_physical_stats view, focusing on the avg_fragmentation_in_percent and page_count metrics. The processing methods include: 30% recommended reconstruction of fragments (REBUILD). The filling factor setting requires reasonable reservation of space to reduce splitting, but it should not be too low. Not all fragments need to be processed, and priority should be determined based on actual access frequency and table size.
2025-07-08
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285
How to rebuild or reorganize an index in SQL?
Article Introduction：To reconstruct or reorganize the SQLServer index to reduce fragmentation and improve query performance, the method should be selected according to the degree of fragmentation: 1. No operation is required when fragmentation is less than 10%. 2. When fragmentation is between 10% and 30%, use ALTERINDEXindex_nameONtable_nameREORGANIZE for reorganization; 3. When fragmentation is more than 30%, use ALTERINDEXindex_nameONtable_nameREBUILD for reconstruction, which can be combined with WITH options such as FILLFACTOR, SORT_IN_TEMPDB and ONLINE to optimize the process; 4. You can query sys.dm_db_inde
2025-08-11
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153
SQL Server Index Maintenance Best Practices
Article Introduction：The key to index maintenance is to judge the fragmentation rate, select maintenance time, and update statistics. 1. Fragment rate
2025-07-31
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268
