Skip to content

Reported rate can be higher than actual when latency is high #80

Open
@tgrabiec

Description

@tgrabiec

In the following output, reported rate is close to 4k rows/s but the actual rate is half that.

scylla-bench executes requests concurrently according to the configured concurrency and emits a partial result from each concurrent fiber if more than a second has elapsed. Those partial results are then summed up together and assumed to have been produced over a period of a second. When latency is high, the period is actually larger than a second, and actual rate lower.

time                operations/s   rows/s   errors  max              99.9th           99th             95th             90th             median           mean             
2.416392808s                4027     4027        0  1.023410175s     1.013972991s     1.007681535s     999.817215ms     996.147199ms     966.262783ms     747.089756ms     
4.448323544s                3485     3485        0  1.035468799s     1.031274495s     1.020788735s     1.014497279s     1.010827263s     993.525759ms     993.77632ms      
6.339966315s                3630     3630        0  1.040711679s     1.029177343s     1.019740159s     1.010302975s     1.002438655s     974.651391ms     964.700896ms     
8.189235084s                3734     3734        0  1.029177343s     1.024458751s     1.013972991s     1.004535807s     998.768639ms     923.271167ms     929.854113ms     

Metadata

Metadata

Assignees

No one assigned

    Labels

    Type

    No type

    Projects

    No projects

    Milestone

    No milestone

    Relationships

    None yet

    Development

    No branches or pull requests

    Issue actions