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  1. WiredTiger
  2. WT-2746

track checkpoint I/O separately from eviction I/O

    Details

    • Type: Improvement
    • Status: Closed
    • Priority: Minor - P4
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: WT2.9.0, 3.3.11, 3.2.10
    • Labels:
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      Description

      Alexander Gorrod writes:

      Something I've been interested in a number of times is knowing how much I/O is done in service of checkpoints versus "normal" eviction. I've always chickened out, since the information isn't available down in __wt_block_write_off where we know how much is being written. The checkpoint I/O smoothing project (WT-2389) would be easier to handle if we tracked the information, so I took a look today.

      How would you feel if I made a change to __wt_block_write so that it takes a set of flags, rather than a bool. At the moment those flags would be:
      WT_BLOCK_WRITE_CKSUM
      WT_BLOCK_WRITE_CALLER_LOCKED
      WT_BLOCK_WRITE_FOR_CHECKPOINT

      I'd also need to pass a flag from __sync_file through reconciliation, indicating that the operation is being done in service of a checkpoint.

      There are other alternatives. For example we could add a check for a (new) checkpointing flag in a session handle down in the block manager.

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            • Assignee:
              keith.bostic Keith Bostic
              Reporter:
              keith.bostic Keith Bostic
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