It may be useful to implement universal method for creating all possible standard indexes for any table

[konard]

https://github.com/deepcase/materialized-path/blob/011c8b6b7464097357d2435b6822aa4003887837/migrations/1633562151439-multidirectional.ts#L158-L182

PostgreSQL limits the number of columns for each index with 32 columns.
Indexes can be created for all possible combination of 1, 2, ... N columns. Where N is not greater than 32, but is configurable by user.
It is well-defined for each of PostgreSQL type which indexes are better suited for that type.
So this stored procedure should have two optional arguments - the maximum number of columns for combined indexes and the restricted set of applied index types (B-tree, hash, etc.).

Once this stored procedure is done, the next step will be to implement a stored procedure that will delete all unused indexes. Used indexes can be checked using stats.

On the second thought, I think it should be a good idea to have a mandatory limitation on the maximum number of columns for combined indexes. If we do not limit it and use 32, we will end up with this number of possible combinations:

Sum[CatalanNumber[i], {i, 1, 32}] = 75 254 198 337 177 847

https://www.wolframalpha.com/input/?i=Sum%5BCatalanNumber%5Bi%5D%2C+%7Bi%2C+1%2C+32%7D%5D

We can use smaller numbers:

Sum[CatalanNumber[i], {i, 1, 16}] = 48760366
Sum[CatalanNumber[i], {i, 1, 8}] = 2055
Sum[CatalanNumber[i], {i, 1, 4}] = 22
Sum[CatalanNumber[i], {i, 1, 2}] = 3