Avoid checking permission of Babelfish temp tables on parallel worker

[Deepesh125]

Consider following facts,

1. Babelfish temp tables are implemented using ENR which is not shared between different backends. So if Parallel worker tries to check permissions on Babelfish then it will fail.
2. Any user should be able to access Babelfish temp tables under given session.
3. Postgres by default does not allow parallel operations on temp tables. Attempt to do so will result in run time error.

Due to above facts, we should avoid permission check on temp tables within parallel workers while ensuring that leader does required permission check on other tables. This commits achieves this behaviour by introducing following three hooks,

ParallelQueryMain_hook -- Hook that allows other extensions to pass on additional details from Leader node to parallel worker. For example, Babelfish extension can pass details of Babelfish temp table defined under current session with Parallel workers.

ExecInitParallelPlan_hook -- Hook that allows Parallel worker to gather additional details passed by Leader node. For example, Babelfish extension can collect the details of Babelfish temp table shared by Leader node so that it can avoid permission checks.

ExecCheckOneRelPerms_hook -- Hook that allows extension control permission checking on given relation/table. For example, Babelfish can use it to avoid permission check on temp tables under parallel worker.

Task: BABEL-5703
Signed-off-by: Dipesh Dhameliya [email protected]
(cherry picked from commit 5e62ffa)

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[Deepesh125]

Merge conflicts -

--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@@ -224,7 -227,10 +227,14 @@@ extern void standard_ExecutorEnd(QueryD
  extern void ExecutorRewind(QueryDesc *queryDesc);
  extern bool ExecCheckPermissions(List *rangeTable,
                                                                 List *rteperminfos, bool ereport_on_violation);
++<<<<<<< HEAD
 +extern void CheckValidResultRel(ResultRelInfo *resultRelInfo, CmdType operation);
++=======
+ /* Wrapper around ExecCheckOneRelPerms */
+ extern bool ExecCheckOneRelPerms_wrapper(RTEPermissionInfo *perminfo);
+ extern void CheckValidResultRel(ResultRelInfo *resultRelInfo, CmdType operation,
+                                                               List *mergeActions);
++>>>>>>> 5e62ffa9bd5 (Avoid checking permission of Babelfish temp tables on parallel worker (#560))

[jsudrik]

Approved.