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Add a system variable to control whether to inline CTE or not #36514

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fixdb opened this issue Jul 25, 2022 · 3 comments · Fixed by #37626 · May be fixed by #37040
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Add a system variable to control whether to inline CTE or not #36514

fixdb opened this issue Jul 25, 2022 · 3 comments · Fixed by #37626 · May be fixed by #37040
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@fixdb
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fixdb commented Jul 25, 2022 •
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Enhancement

Currently, CTE can only be inlined through MERGE() hint. But for those queries that have many CTEs, and queries that are generated by BI, it is better to have a system variable to control whether to inline CTE or not.
Suggested var name:
tidb_opt_inline_cte

NB. MERGE() hint can override the tidb_opt_inline_cte variable.
@fixdb fixdb added the type/enhancement The issue or PR belongs to an enhancement. label Jul 25, 2022
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/assign @dayicklp

@dayicklp dayicklp mentioned this issue Jul 25, 2022
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@dayicklp dayicklp mentioned this issue Aug 11, 2022
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@elsa0520 elsa0520 mentioned this issue Sep 5, 2022
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elsa0520 commented Sep 5, 2022

docs: https://github.com/pingcap/docs/pull/10343

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elsa0520 commented Sep 5, 2022

please assign to me ~

@elsa0520 elsa0520 mentioned this issue Sep 5, 2022
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elsa0520 added a commit to elsa0520/tidb that referenced this issue Sep 7, 2022
@elsa0520
planner: add a session variable "tidb_opt_inline_cte"
9bfa8f2 
This pr adds a new session variable,
which is mainly used to control whether all CTEs in the entire session are inlined or not.
The default value is false, which means that inline cte is not enabled by default.
(But if the user directly specifies the merge hint, it can still be turned on)
If the variable is set to true, it means that all CTEs for this session try to enable inlining.

Fixed pingcap#36514
ti-chi-bot pushed a commit that referenced this issue Sep 8, 2022
@elsa0520
session, planner: add a session variable "tidb_opt_force_inline_cte" (#…
ca5de89 
…37626)

close #36514
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@fixdb @dayicklp @elsa0520