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  1. WiredTiger
  2. WT-1839

Add an initial implementation of named, in-memory snapshots

    Details

    • Type: Task
    • Status: Closed
    • Priority: Major - P3
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: WT2.6.1
    • Labels:
      None

      Description

      This implementation is mainly intended to flesh out the API. It won't cope well with very large numbers of active snapshots, ignores some misuses of the interface and doesn't deal at all with the problem of converting snapshots to on-disk checkpoints.

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          agorrod Alex Gorrod added a comment -

          @RedBeard0531 says:

          > We don't need to write to a snapshot but it would be ideal if a single session/transaction could read from a snapshot but still do writes.

          I'd been assuming snapshots would re-use some transaction ID state from the sessions transaction. It's possible that we can implement snapshots in a way that is decoupled from transactions, but I'm not sure yet. This comment is to keep the goal in mind while implementing the functionality.

          The alternative would be for applications to have multiple sessions open, but it would be good to avoid session handle bloat if possible.

          Show
          agorrod Alex Gorrod added a comment - @RedBeard0531 says: > We don't need to write to a snapshot but it would be ideal if a single session/transaction could read from a snapshot but still do writes. I'd been assuming snapshots would re-use some transaction ID state from the sessions transaction. It's possible that we can implement snapshots in a way that is decoupled from transactions, but I'm not sure yet. This comment is to keep the goal in mind while implementing the functionality. The alternative would be for applications to have multiple sessions open, but it would be good to avoid session handle bloat if possible.
          Show
          ramon.fernandez Ramon Fernandez added a comment - Additional ticket information from GitHub Commits in this ticket: 7f1998be92d49435a23f7f42ef5b438a133f881f 03c624158110c5190c965a5be057993a9afb8853 0fb36c67305c3219bda25ba189c951b5bac72821 cddde3c0d0e98a16eea40a0596d7f01c78566045 0a590331fdf5176ebbfbc6cb73a84c98b78d7af3 7609a565a11952c2ca14642dc2c837552dc1e86a
          Hide
          xgen-internal-githook Githook User added a comment -

          Author:

          {u'username': u'michaelcahill', u'name': u'Michael Cahill', u'email': u'michael.cahill@mongodb.com'}

          Message: Fix the default values for named snapshot drop before/to.

          refs WT-1839
          Branch: develop
          https://github.com/wiredtiger/wiredtiger/commit/c8452143a5f79f320592f2c10150b4e7341ff731

          Show
          xgen-internal-githook Githook User added a comment - Author: {u'username': u'michaelcahill', u'name': u'Michael Cahill', u'email': u'michael.cahill@mongodb.com'} Message: Fix the default values for named snapshot drop before/to. refs WT-1839 Branch: develop https://github.com/wiredtiger/wiredtiger/commit/c8452143a5f79f320592f2c10150b4e7341ff731

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              Dates

              • Created:
                Updated:
                Resolved:
                Days since reply:
                2 years, 1 week ago
                Date of 1st Reply: