G
George Potemkin
Guest
For terrabyte databases the main factor that affects the performance of the reads from disks is a seek time. Slowness is growing much faster than db size. Also the record fragmentation "hurts" performance much stonger in the large databases. In presentation "DBAnalys To The Rescue!" we had an example: Table size: 25.5G 20% records are fragmented 33.6% blocks are on RM Chain Reads of the whole table from disk was 35 times slower than when all records are not fragmented. Fortunately the record fragmentation can be fixed online. Seek time factor can be eliminated by SSD disks.
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