[SERVER-63740] Investigate pushing down $lookup stages against a regular collection even if other secondary collections are sharded or are views Created: 16/Feb/22 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: | Improvement | Priority: | Major - P3 |
| Reporter: | Mihai Andrei | Assignee: | Backlog - Query Execution |
| Resolution: | Unresolved | Votes: | 0 |
| Labels: | post-rc0, read-only-views | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Assigned Teams: |
Query Execution
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| Participants: |
| Description |
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Suppose we have an aggregate pipeline consisting of two $lookups, the first of which targets a ‘from’ collection that is neither sharded nor a view, but the second of which is a view (or sharded). Currently, when the AutoGet for multiple collections is acquired, the fact that one of the secondary namespaces is sharded/a view will inhibit the pushdown of any $lookup stages in the front of the pipeline that target regular collections . This ticket tracks the work to relax this restriction so that any $lookup stage in the front of the pipeline can be pushed down, even if later $lookup stages target views or sharded collections. |