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6.830 Lecture 6

Lab 1 Tutorial – Tomorrow, 7 PM, 32-144. 6.830 Lecture 6. Cost Estimation and Access Methods. Study Break. Assuming disk can do 100 MB/sec I/O And the following schema: grades ( cid int , g _sid int , grade char(2)) s tudents ( s_int , name char(100))

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6.830 Lecture 6

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  1. Lab 1 Tutorial – Tomorrow, 7 PM, 32-144 6.830 Lecture 6 Cost Estimation and Access Methods

  2. Study Break • Assuming disk can do 100 MB/sec I/O • And the following schema: grades (cidint, g_sidint, grade char(2)) students (s_int, name char(100)) • Estimate time to sequentially scan grades, assuming it contains 1M records (Consider: field sizes, headers) • Estimate time to join these two tables, using nested loops, assuming students fits in memory but grades does not, and students contains 10K records.

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