perf: reduce memory consumption across services#1047
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nledez wants to merge 2 commits intocgwire:mainfrom
Open
perf: reduce memory consumption across services#1047nledez wants to merge 2 commits intocgwire:mainfrom
nledez wants to merge 2 commits intocgwire:mainfrom
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| assignees = db.relationship( | ||
| "Person", secondary=TaskPersonLink.__table__, lazy="selectin" | ||
| ) | ||
| assignees = db.relationship("Person", secondary=TaskPersonLink.__table__) |
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Please keep the selectin selection. It is more adapted to our case, where most consuming queries need it.
- Fix N+1 queries in get_comments() by batch-fetching persons - Stream preview files in backup_service with yield_per(500) - Use with_entities for preview file lookup in playlists_service - Replace manual dict init patterns with defaultdict - Flush index documents in batches instead of accumulating - Change Task.assignees from eager selectin to lazy loading, add explicit selectinload only where assignees are accessed
Use yield_per(500) and Flask streaming response to avoid loading entire query results and building the full CSV string in memory.
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Problem
Several SQLAlchemy patterns cause excessive memory usage: Task.assignees is eagerly loaded via selectin on every query (70-80% don't need it), get_comments() triggers N+1 queries fetching persons one by one, backup_service loads all preview files into memory at once, and playlists_service fetches full ORM objects when only 2 fields are needed.
Solution