geqo_threshold
Use genetic query optimization to plan queries with at least this many FROM items involved. (Note that a FULL OUTER JOIN construct counts as only one FROM item.) The default is 12. For simpler queries it is usually best to use the regular, exhaustive-search planner, but for queries with many tables the exhaustive search takes too long, often longer than the penalty of executing a suboptimal plan. Thus, a threshold on the size of the query is a convenient way to manage use of GEQO.
英文手册覆盖始于 PostgreSQL 7.4. 来源历史与运行验证各自保留独立版本边界。
当前阅读 PG 18·选择有来源记录的版本
此版本暂无所选语言的定义，以下显示原始英文内容。
- boot val
- 12
- category
- Query Tuning / Genetic Query Optimizer
- context
- user
- documented
- true
- enumvals
- 未知
- extra desc
- 未知
- lang
- en
- max val
- 2147483647
- metadata version
- 18
- min val
- 2
- name
- geqo_threshold
- short desc
- Sets the threshold of FROM items beyond which GEQO is used.
- source
- pg-settings-source-snapshot
- unit
- 未知
- vartype
- integer
版本定义 PG 18
Use genetic query optimization to plan queries with at least this many FROM items involved. (Note that a FULL OUTER JOIN construct counts as only one FROM item.) The default is 12. For simpler queries it is usually best to use the regular, exhaustive-search planner, but for queries with many tables the exhaustive search takes too long, often longer than the penalty of executing a suboptimal plan. Thus, a threshold on the size of the query is a convenient way to manage use of GEQO.
比较版本
来源引用
定义来源
center · PostgreSQL 18 · english-manuals:5acb90a6e7888c81d644fb17938537b9f7b77409440da689d78745a7042fcd72
正文语言: en · english-manuals:5acb90a6e7888c81d644fb17938537b9f7b77409440da689d78745a7042fcd72