Have you tried locking the APEX procedures in memory using
DBMS_SHARED_POOL.KEEP? That is the usual way of dealing with library
latches.
Regards
On 4/2/19 11:10 AM, Chris Taylor 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
