That seems to explain the library cache issue as well that I don't get with
my own DBA account. Since its going through a package to execute SQL
commands, the library cache issues could be in a few places. (Reminds me
of dynamic SQL performance problems seen in the past)
Chris
On Tue, Apr 2, 2019 at 10:16 AM Howard Latham <howard.latham@xxxxxxxxx>
wrote:
Here is the link to the Article!
https://dsavenko.me/how-apex-executes-sql-statements-without-having-permissions/
Howard A. Latham
On Tue, 2 Apr 2019 at 16:11, Chris Taylor <
christopherdtaylor1994@xxxxxxxxx> wrote:
Env:
Exadata Cloud @ Customer
RAC DB: 12.1.0.2 (Multi-tenant)
Ok team, I'll be the first to admit I don't know a lot about APEX and how
it plays with the database.
We have a query that runs from a middleware server where the page is
built in APEX and connects to the DB as APEX_PUBLIC_USER to execute queries.
This one query (which is really ugly and annoying) involves SEVERAL
views from another schema like so:
(Owners & Names changed to protect the innocent)
USERNAME.VIEW_1
USERNAME.VIEW_2
USERNAME.VIEW_3
The APEX_PUBLIC_USER session goes into a spin on library cache
lock/library cache pin waits when trying to run this particular query.
I spent all day yesterday trying to tune the query from my DBA account
and couldn't figure it out.
Today I logged in as the APEX_PUBLIC_USER account and I figure out that
there are NO grants on these views to ANYONE. Yet, the query will
eventually return when executed from the middleware server.
The query will error if I login as APEX_PUBLIC_USER directly with "Object
does not exist" (because no grants).
Gathering FIXED_OBJECT_STATISTICS & GATHER_DICTIONARY_STATS seems to fix
the problem but I'm super confused about how this query can even run when
its executing as APEX_PUBLIC_USER when it doesn't have privileges on the
VIEWs used by the query.
TL;DR:
1. Gathering FIXED_OBJECT_STATISTICS & GATHER_DICTIONARY_STATS helps
resolve the library cache lock/library cache pin spins and query returns
2. How does APEX_PUBLIC_USER get the necessary rights to the Views if
there are no grants on the views in the database?
Chris Taylor