How to Confirm if PostgreSQL Used GEQO for a Specific Query? - Stack Overflow

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How can we verify if PostgreSQL used GEQO for a specific query execution? Are there specific log entries, EXPLAIN output indicators, or planner statistics that explicitly confirm GEQO was used?"

I want to determine whether PostgreSQL's Genetic Query Optimizer (GEQO) was applied to a particular query, especially when dealing with complex joins exceeding the geqo_threshold.

Are there log messages that explicitly indicate GEQO was used? Can EXPLAIN (ANALYZE, VERBOSE) reveal GEQO-related details in the plan? Do planner statistics provide any concrete way to confirm GEQO usage? Are there other methods to verify if GEQO influenced the join order selection? I am looking for a definitive way to confirm whether PostgreSQL engaged GEQO for optimizing a specific query

I have tried get if geqo was used in logs.I have also changed the geqo_treshold=2.I have checked the geqo is ON.I am joing more than 12 tables.I have tried to check if there are any changes in the query plan by using EXPLAIN ANALYZE function.

How can we verify if PostgreSQL used GEQO for a specific query execution? Are there specific log entries, EXPLAIN output indicators, or planner statistics that explicitly confirm GEQO was used?"

I want to determine whether PostgreSQL's Genetic Query Optimizer (GEQO) was applied to a particular query, especially when dealing with complex joins exceeding the geqo_threshold.

Are there log messages that explicitly indicate GEQO was used? Can EXPLAIN (ANALYZE, VERBOSE) reveal GEQO-related details in the plan? Do planner statistics provide any concrete way to confirm GEQO usage? Are there other methods to verify if GEQO influenced the join order selection? I am looking for a definitive way to confirm whether PostgreSQL engaged GEQO for optimizing a specific query

I have tried get if geqo was used in logs.I have also changed the geqo_treshold=2.I have checked the geqo is ON.I am joing more than 12 tables.I have tried to check if there are any changes in the query plan by using EXPLAIN ANALYZE function.

• postgresql
• query-optimization
• query-planner

Share Improve this question Follow asked Mar 13 at 10:18 Mridula KurneMridula Kurne 1111 bronze badge

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PostgreSQL won't emit a message or show anything special in the EXPLAIN output if the genetic query optimizer was used to generate the plan.

There are only two things that can indicate the use of GEQO:

1. if you run EXPLAIN several times, you end up with different plans because of the randomness involved (but if you see no variation, that's not a proof that GEQO was not used)

2. if the query joins more than geqo_threshold relations.

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