In this post, I am sharing few important parameters for configuring the Query planner of PostgreSQL.

I found this help on official PostgreSQL page, so I am sharing from there.
Reference link:

For the Query optimization, these parameters are very important, so I copied and sharing same information from the official page.

Made list of few important parameters:

These configuration parameters provide a crude method of influencing the query plans chosen by the query optimizer.

If the default plan chosen by the optimizer for a particular query is not optimal, a temporary solution is to use one of these configuration parameters to force the optimizer to choose a different plan.

enable_indexscan (boolean): Enables or disables the query planner’s use of index-scan plan types. The default is on

enable_hashjoin (boolean): Enables or disables the query planner’s use of hash-join plan types. The default is on

enable_hashagg (boolean): Enables or disables the query planner’s use of hashed aggregation plan types. The default is on

enable_mergejoin (boolean): Enables or disables the query planner’s use of merge-join plan types. The default is on

enable_nestloop (boolean): Enables or disables the query planner’s use of nested-loop join plans. It is impossible to suppress nested-loop joins entirely, but turning this variable off discourages the planner from using one if there are other methods available. The default is on

enable_seqscan (boolean): Enables or disables the query planner’s use of sequential scan plan types. It is impossible to suppress sequential scans entirely, but turning this variable off discourages the planner from using one if there are other methods available. The default is on

enable_sort (boolean): Enables or disables the query planner’s use of explicit sort steps. It is impossible to suppress explicit sorts entirely, but turning this variable off discourages the planner from using one if there are other methods available. The default is on