Uploaded image for project: 'WiredTiger'
  1. WiredTiger
  2. WT-9864

Improve compact messages about "skipped" pages

    • Storage Engines
    • 3
    • Storage Engines - 2022-10-03

      Summary

      When compact runs, it prints several types of messages that describe the work it has done. These messages describe the number of pages "reviewed", "skipped", and "rewritten". Several times recently customers and/or TSEs have misinterpreted the use of "skipped" here, inferring that it means that compact is somehow not copying a page that it should. 

      We should reword these messages to eliminate this ambiguity.

      In this context, "skipped" pages are pages that where compact looked at the address and decided that the page should not be rewritten because the page is not on the end part of the file. So it is completely normal to have a large number of skipped pages.

      We could try to find a less ambiguous wording, but my recommendation would be to simply not report on "skipped" pages. It doesn't seem like useful information in this context. A user might want to know how many pages (i.e, what fraction of the file) have been examined (i.e., "reviewed") and how many pages have been copied (i.e., "rewritten"). But I can't see a reason the remaining pages are interesting. And if a user really wants that information, they can figure it out by subtracting "rewritten" from "reviewed".

            Assignee:
            ruby.chen@mongodb.com Ruby Chen
            Reporter:
            keith.smith@mongodb.com Keith Smith
            Votes:
            1 Vote for this issue
            Watchers:
            4 Start watching this issue

              Created:
              Updated:
              Resolved: