Chengpeng Yan

## Enhancement Now, there are less logs for the binding operation. We should add more logs for it. That may help us to trouble shooting easily.

add a cbo Introduction document

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### What issue does this PR solve? - close https://github.com/pingcap/tidb-dev-guide/issues/80 ### What is changed: Add an introduction to cost-based optimization.

Shouldn't push down the topN when the result for the order by item is uncertain

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## Bug Report Please answer these questions before submitting your issue. Thanks! ### 1. Minimal reproduce step (Required) ``` drop table if exists t3; CREATE TABLE t3(c0 INT, primary key(c0));...

planner: don't push down topN when the expressions in projection is mutable effective

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…utable effective ### What problem does this PR solve? Issue Number: close https://github.com/pingcap/tidb/issues/37986 Problem Summary: planner: don't push down topN when the expressions in projection is mutable effective ### What...

planner: don't push down some conditions to projections

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### What problem does this PR solve? Issue Number: close https://github.com/pingcap/tidb/issues/35623 close https://github.com/pingcap/tidb/issues/37971 Problem Summary: Some conditions shouldn't be pushed down to projection. ### What is changed and how it...

Some statements may be too long and consume too much memory when using the Plan Cache

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## Enhancement Some queries may be too long and consume too much memory when using the Plan Cache. For example, `in` with large lists. For a single query that consumes...

support extended list types

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Related to https://github.com/duckdb/pg_duckdb/issues/101 This pull request adds more array types. The changes include: 1. Extended Array Type Support: * Added support for additional array types including CHAR, SMALLINT, VARCHAR, TIMESTAMP,...

planner: add more test cases for plan cache aware of binding

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### What problem does this PR solve? Issue Number: ref https://github.com/pingcap/tidb/issues/29539 Problem Summary: add more test cases for plan cache aware of binding ### What is changed and how it...