HANA: xsodata: Huge performance gap between first and 2nd request execution - odata

Question

If I expose a VIEW
CREATE VIEW myView AS
SELECT ...
FROM ...
via xsodata
service namespace "oData" {
entity "mySchema"."myView" as "myView";
}
and GET /myView for the first time after VIEW creation the performance is very low:
However: After performing the same request again (and everytime after that) the performance is what I want it to be:
Questions:
Why?
How to avoid the first long-running request?
Already tried:
Execution of the sql profiler-output (without statement preparation) in HANA Studios SQL console gives good performance always
Table hotloading (LOAD myTable ALL;) had no effect
Update
We found out the "Why"-Part: xs-engine is running the query as a prepared statement even if there are no parameters in the request. On first execution (within the user's context) the query gets perpared, resulting in an entry in M_SQL_PLAN_CACHE (SELECT * FROM M_SQL_PLAN_CACHE WHERE USER_NAME = 'myUser'). Clearing the plan cache (ALTER SYSTEM CLEAR SQL PLAN CACHE) makes the oData request slow again, leading to the assumption that the performance gap lies in the re-preparation of the query.
We are now stuck with the 2nd question: How to avoid that? Our approach to mark certain plan cache entries for recompilation (ALTER SYSTEM RECOMPILE SQL PLAN CACHE ENTRY 123) just invalidated the entry and did not update it automatically...

Answer 1

I'm not to sure you can REMOVE the first execution long time, but you can try changing the view to a Calculation View executed in the SQL Engine.
HANA is been super optimized for using its Calculation Views, and the Plan Cache should run faster with them, maybe reducing the first execution time significantly. Also, Plan Cache of Calc. Views should be shared between users (since _SYS_REPO is the one who generates them).
If you use the script version I believe you could reuse a lot of your current SQL, but you can also try using the graphical approach as well.
Let us know if you had any luck. Modeling with Big Data is always a surprise.