Re: Faster "SET search_path"

Noah Misch <noah@leadboat.com>

From: Noah Misch <noah@leadboat.com>
To: Jeff Davis <pgsql@j-davis.com>
Cc: Nathan Bossart <nathandbossart@gmail.com>, Isaac Morland <isaac.morland@gmail.com>, pgsql-hackers@postgresql.org
Date: 2024-07-09T00:20:11Z
Lists: pgsql-hackers
On Mon, Jul 08, 2024 at 04:39:21PM -0700, Jeff Davis wrote:
> On Sun, 2024-06-30 at 15:30 -0700, Noah Misch wrote:
> > You're caching the result of object_aclcheck(NamespaceRelationId,
> > ...), so
> > pg_auth_members changes
> 
> Thank you for the report.
> 
> Question: to check for changes to pg_auth_members, it seems like either
> AUTHMEMROLEMEM or AUTHMEMMEMROLE work, and to use both would be
> redundant. Am I missing something, or should I just pick one
> arbitrarily (or by some convention)?

One suffices.  initialize_acl() is the only other place that invals on this
catalog, so consider it a fine convention to mimic.

> >  and pg_database changes also need to invalidate this
> > cache.  (pg_database affects the ACL_CREATE_TEMP case in
> > pg_namespace_aclmask_ext()
> 
> I am having trouble finding an actual problem with ACL_CREATE_TEMP.
> search_path ACL checks are normally bypassed for the temp namespace, so
> it can only happen when the actual temp namespace name (e.g.
> pg_temp_NNN) is explicitly included. In that case, the mask is
> ACL_USAGE, so the two branches in pg_namespace_aclmask_ext() are
> equivalent, right?

I don't know.

> This question is not terribly important for the fix, because
> invalidating for each pg_database change is still necessary as you
> point out



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.