Strange query by oracle_fdw

Question

I am using oracle_fdw 2.2.0devel, PostgreSQL 10.13, Oracle client 18.3.0.0.0

We have a foreign table in Postgres defined as this:

CREATE FOREIGN TABLE public.tickers
(
   ticker_id         INTEGER,
   ticker            VARCHAR,
)
SERVER oracle
OPTIONS (table 'TICKERS', schema 'COMMENTARY', readonly 'true');

This is connecting to as 12c SE database. This works fine, however, I've noticed that the query in Oracle is actually looking like this:

SELECT  
   /*618157932326e692807010156f98ddac*/  
   r2."TICKER_ID",  
   r2."TICKER"  
FROM "COMMENTARY"."TICKERS" r2  
WHERE (upper(r2."TICKER") = upper(:p1))

Why would it automatically be adding the "UPPER" clause? This slows the Oracle query and does not use an index, unless I create a FBI using "upper".

Was wondering if there was some option I'm supposed to disable.......

Answer 1

The only way that oracle_fdw will generate an Oracle query that uses the upper function is if the original PostgreSQL query already had upper in it.