Handle mispredictions cleanly. #12
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In the real world, we might mess up when naming a partition. This should be rare if partitionmanager is running often, since it'll rename partitions to match reality, but when it's running only rarely, things get out of date. This change avoids attempting to calculate rates-of-change using partitions that don't make sense - e.g., today is July 1, and our active partition says it starts in a week. That is plainly wrong, but we can still use our current rate-of-change.
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This was rolled into PR #4 |
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Turns out this was only partially rolled into PR #4, and there was another edge case uncovered. |
jcjones
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Sep 20, 2021
In the real world, we might mess up when naming a partition. This should be rare if partitionmanager is running often, since it'll rename partitions to match reality, but when it's running only rarely, things get out of date. This change avoids attempting to calculate rates-of-change using partitions that don't make sense - e.g., today is July 1, and our active partition says it starts in a week. That is plainly wrong, but we can still use our current rate-of-change. This expands on PR #12 by changing what the start-datetime is for new partitions after we mispredicted - without this change, if we had partitions through to December, but it's only August and we need more, the new partitions would be named for January instead of reflecting reality that they need to be named for Right Now. This also catches a bug where we could get timestamp name collisions. This is a lot less of an issue when I implement Tim's suggestion in #19, but for now this just increases dates by a day to avoid a collision, and that works well.
jcjones
added a commit
that referenced
this pull request
Sep 21, 2021
In the real world, we might mess up when naming a partition. This should be rare if partitionmanager is running often, since it'll rename partitions to match reality, but when it's running only rarely, things get out of date. This change avoids attempting to calculate rates-of-change using partitions that don't make sense - e.g., today is July 1, and our active partition says it starts in a week. That is plainly wrong, but we can still use our current rate-of-change. This expands on PR #12 by changing what the start-datetime is for new partitions after we mispredicted - without this change, if we had partitions through to December, but it's only August and we need more, the new partitions would be named for January instead of reflecting reality that they need to be named for Right Now. This also catches a bug where we could get timestamp name collisions. This is a lot less of an issue when I implement Tim's suggestion in #19, but for now this just increases dates by a day to avoid a collision, and that works well.
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In the real world, we might mess up when naming a partition. This should be
rare if partitionmanager is running often, since it'll rename partitions
to match reality, but when it's running only rarely, things get out of date.
This change avoids attempting to calculate rates-of-change using partitions
that don't make sense - e.g., today is July 1, and our active partition
says it starts in a week. That is plainly wrong, but we can still use our
current rate-of-change.