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**Use case**
I'd like to use `chdb` as a query engine for a custom storage engine implemented in Python.
**Describe the solution you'd like**
Pass some kind of filters to `PyReader#read` meth…
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When someone projects an expression from values node, we should be able to inline and simplify those into the value node itself. Today we don't do that:
```
presto:di> explain select substr(x, 1,2…
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### Problem description
Filter pushdown (in the database often called predicate pushdown but that is confusing in RDF ;) ) is way to move filter evaluation into the equivalent of the [getStatement](h…
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It currently appears that predicate pushdown isn't applied before calculating what Parquet files are included in scanning the table's data.
The AVRO manifest files include statistics about each Par…
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## Enhancement
tidb_opt_projection_push_down is introduced by #27029 , and is set 'off' by default, still not GA now.
It aimed to improve performance in two sides:
1. Utilize distributed tikv nod…
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I don't think it's currently possible to efficiently filter by a [DBRef](https://www.mongodb.com/docs/manual/reference/database-references/) field.
While dereference pushdown is supported it is [ex…
nsaje updated
2 months ago
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A window function (`OVER` clause) is currently translated to a complicated pattern in the HIR-to-MIR lowering. This prevents `ProjectionPushdown` from realizing if a window function and later operatio…
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### What happens?
The query plan for the query mentioned below rearranges the predicate `WHERE position('*' in b) = 0` such that it is executed *after* the cast which leads to an error. Since predica…
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Follow up tasks from https://github.com/MaterializeInc/incidents-and-escalations/issues/24:
* [ ] Consider making stats best effort, so that we never need to block. Then there's no cancellation i…