Materialized view scalar subqueries #32811
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This way we can reuse scalars from other queries (non MVs) and leave the door open for future improvements
robot-clickhouse
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pr-bugfix
vdimir
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Dec 16, 2021
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Changelog category (leave one):
Changelog entry (a user-readable short description of the changes that goes to CHANGELOG.md):
Avoid reusing the scalar subquery cache when processing MV blocks. This fixes a bug when the scalar query reference the source table but it means that all subscalar queries in the MV definition will be calculated for each block.
Detailed description / Documentation draft:
Related to the issue reported in #9587 (comment)
I'm not super happy with the solution. As I mentioned in a comment the ideal situation would be that we only discard scalar results if the source table was involved.