shahidki31 opened a new pull request #32659:
URL: https://github.com/apache/spark/pull/32659
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### What changes were proposed in this pull request?
If the grouping keys contains substring, Aggregate doesn't use CBO for
computing stats and fall back to sizeInBytes based estimation. So we will be
missing row count and col stats after that. Many TPCDS queries has substring in
their group by expressions, like Query8, Query23a etc.
### Why are the changes needed?
CBO cannot estimate rowcount if the groupby clause of a query involves the
expression substring. For example, we can not estimate the row count of the
following query, extracted from TPC-DS queries and based on the TPC-DS schema:
**Eg: Query**
`SELECT item.i_brand, count(1), date_dim.d_year, item.i_brand_id,
sum(store_sales.ss_ext_sales_price) AS ext_price, item.i_item_sk
FROM store_sales INNER JOIN date_dim ON (date_dim.d_date_sk =
store_sales.ss_sold_date_sk) INNER JOIN item ON (store_sales.ss_item_sk =
item.i_item_sk)
GROUP BY item.i_brand, date_dim.d_date, substring(item.i_item_desc, 1, 30),
date_dim.d_year, item.i_brand_id, item.i_item_sk`
**Before:**
No rowcount
**After:**
Rowcount exists
### Does this PR introduce _any_ user-facing change?
No
### How was this patch tested?
Added UTs, manual testing
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