Initial sync must copy in-progress index builds along with built indexes for two-phase index builds. v4.0 Index builds write a createIndexes oplog entry upon completion, which allows v4.0 initial sync to ignore in-progress index builds and instead rely on seeing the oplog entry during the oplog catch-up phase. Two-phase index builds, however, write oplog entries prior to completion that will not exist in the part of the oplog that initial sync reads during catch-up.
- is related to
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SERVER-25175 listIndexes shouldn't include in-progress background index builds on primary nodes
- Closed
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SERVER-37839 Identify in-progress index builds as building in the index specs that the listIndexes command returns
- Closed