[core] Fast return if rollback verion equals lastest version #4467
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| @@ -625,14 +630,19 @@ public void rollbackTo(String tagName) { | |||
| checkArgument(tagManager.tagExists(tagName), "Rollback tag '%s' doesn't exist.", tagName); | |||
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| Snapshot taggedSnapshot = tagManager.taggedSnapshot(tagName); | |||
| SnapshotManager snapshotManager = snapshotManager(); | |||
| @@ -512,6 +512,11 @@ public void rollbackTo(long snapshotId) { | |||
| "Rollback snapshot '%s' doesn't exist.", | |||
| snapshotId); | |||
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| // fast return | |||
| if (new Long(snapshotId).equals(snapshotManager.latestSnapshotId())) { | |||
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I think new Long has a little strange.
Why not:
Long latestSnapshotId = snapshotManager.latestSnapshotId();
if (latestSnapshotId == null) {
exception or error log
}
if (taggedSnapshot.id() == latestSnapshotId) {
fast return
}
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A question: |
In this case, the result is not what the user wants. But although there does not fast return, this case may also occur. For example, the rollback snapshot is 1 and the latest snapshot of table is also 1, before rollback ends the lastest snapshot of table changes to 2 or 3, the rollback logic gets the lastest shotshot is diffcult to keep always the newest, this will cause some new snapshots not to be processed. |
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Hi @askwang , what is this PR aims to? just for performance? |
yes, juse fast return, no need to execute RollbackHelper#cleanLargerThan. |
Do we need to care about the speed of this operation? I think it should be very fast even no optimization. |
Purpose
If the rollback snapshot version is equal to the lastest snapshot version, we should fast return.
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