Horton

Re: Faster "SET search_path"

Jeff Davis <pgsql@j-davis.com>

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From: Jeff Davis <pgsql@j-davis.com>
To: Isaac Morland <isaac.morland@gmail.com>
Cc: pgsql-hackers@postgresql.org
Date: 2023-08-01T05:28:31Z
Lists: pgsql-hackers 
On Sat, 2023-07-29 at 12:44 -0400, Isaac Morland wrote:
> Essentially, "just" observe efficiently (somehow) that no change is
> needed, and skip changing it?

I gave this a try and it speeds things up some more.

There might be a surprise factor with an optimization like that,
though. If someone becomes accustomed to the function running fast,
then changing the search_path in the caller could slow things down a
lot and it would be hard for the user to understand what happened.

Also, there are a few implementation complexities because I think we
need to still trigger the same invalidation that happens in
assign_search_path().

Regards,
	Jeff Davis

Commits

  1. Fix missing invalidations for search_path cache.

  2. Optimize SearchPathCache by saving the last entry.

  3. Optimize check_search_path() by using SearchPathCache.

  4. Be more paranoid about OOM in search_path cache.

  5. Add cache for recomputeNamespacePath().

  6. Transform proconfig for faster execution.