Select in read only transaction mode / insert in write mode

Question

hello,
i have a following question: i have 2 db, one is rdb and one oracle
im extracting data out of table out of rdb and inserting them into oracle via OWB;
however this is run in read-write mode and causes locks in rdb; the only way to prevent locks is to run a select statement that accesses rdb in 'read only' transaction mode;
my question is: is this possible to split up the select and insert statements of oracle into 2 different transaction modes, so that select statement is run in 'read-only' mode and insert in 'write' mode?
i appreicate tips on how this could be achieved
thx
rgds

Answer 1

Hello,
is this something like:
insert into oracle_table (select * from rdb_table@rdb_link);
Then it is easy, you just need to use an sql init file for your OCI Service. Create a file, e.g. sql_init.ini that contains this line:
declare transaction read only;
Then alter your service so that it sees the sql init file, e.g.:
SQLSRV> alter service <your OCI service> sql_init_file sql_init.ini
The service owner must have the privileges to read the file. You need to restart the OCI service.
Then a statement of the above kind results in a read only transaction on Rdb side, and the insert on Oracle side is done.
I hope your SQL/Services version is a recent one (actual version is 7.3.1), because of this (from the SQL/Services Release Notes 7.2.0.1):
5.4.25 Declare Transaction in SQL Init File Being Overridden
In releases of OCI Services for Oracle Rdb prior to 7.2.0.1, if a DECLARE
TRANSACTION statement was executed in the SQL initialization file of a service, it would
be overridden by a DECLARE TRANSACTION statement executed later by OCI Services
for Oracle Rdb. Toward the end of the connection setup, OCI Services for Oracle Rdb would
execute a DECLARE TRANSACTION statement to set the default transaction
characteristics to be close to Oracle default transaction characteristics. This would supersede
any DECLARE TRANSACTION statement in the SQL initialization file. Starting with
release 7.2.0.1, OCI Services for Oracle Rdb recognizes that a DECLARE TRANSACTION
statement has been executed and will not execute another one.
Regards
Wolfgang
P.S.: It is always better to place Rdb related questions in our communities at https://communities.oracle.com/portal/server.pt/community/rdb_product_family_on_openvms . Those are watched by Rdb Engineering and Support. It was by pure chance that I saw this forum thread.