[SERVER-59444] Enable lock-free reads with multi-document transactions Created: 19/Aug/21 Updated: 06/Dec/22 |
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| Status: | Backlog |
| Project: | Core Server |
| Component/s: | None |
| Affects Version/s: | None |
| Fix Version/s: | None |
| Type: | Task | Priority: | Major - P3 |
| Reporter: | Dianna Hohensee (Inactive) | Assignee: | Backlog - Storage Execution Team |
| Resolution: | Unresolved | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Issue Links: |
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| Assigned Teams: |
Storage Execution
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| Description |
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In theory, this should not be too difficult, but would take some work. Multi-document transactions save the RecoveryUnit (and thus snapshot) and locks held (LockerImpl) across operations/commands. Lock-free reads store the CollectionCatalog on the opCtx, so any new collections accessed can be from the same point-in-time view of the catalog: we would need to save this for the multi-doc transaction like the RecoveryUnit and LockerImpl is saved today. The part I'm unfamiliar with is how storage snapshots are handled in multi-document transactions, whether they can ever be reset. If snapshot resets happen, then that would make it a little trickier to handle a stored CollectionCatalog – the CollectionCatalog would need refreshing, too, to maintain the same catalog view in-memory and on-disk. |
| Comments |
| Comment by Yuhong Zhang [ 19/Aug/21 ] |
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We would want to prototype on the project and timebox it in one sprint. |
| Comment by Dianna Hohensee (Inactive) [ 19/Aug/21 ] |
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Note:
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