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I don't understand what the difference between workload A (50% read, 50% update) and workload F(50% read, 50% read-modify-write) update isn't read-modify-write ? what the difference between read operation and scan operation ? i don't understand exactly what the signification of thread ? (number of request or number of client ?) please help. thanks

user11222729
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You have multiple questions. I am answering the first one, which is the one described in the title.

Update modifies a record without reading it first (though it may read it first by chance, as part of the read operations in the workload). Read-modify-update, as the name indicates, reads the value of a record, modifies it and writes the new value. They are both updates indeed, but the access pattern is different.

Ref: https://github.com/brianfrankcooper/YCSB/wiki/Core-Workloads

cabad
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  • thanks. can you explain the signification of a thread ? – user11222729 Jul 10 '22 at 16:44
  • There's not enough context to answer that question. Are you talking about the computer / OS concept of thread? or are you talking about the example provided in the YCSB documentation (threaded conversations in social networks). In either case, this is outside the scope of this question (and stackoverflow, really). – cabad Jul 11 '22 at 22:29
  • Hello,I talk about threads in YCSB. What means number oh threads = 2 or number of threads = 64 in YCSB. Thanks. – user11222729 Jul 17 '22 at 11:51
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    Look up the definition of thread in Operating Systems textbooks. Each thread executes concurrently. In YCSB, that would mean simulating multiple simultaneous clients issuing requests. – cabad Jul 17 '22 at 14:16