SAP instance communication with Oracle processes

[Former Member]

Can anybody please explain me how SAP instance communicate with Oracle processes ?

Also some details on OPS$, SID.ADM etc accounts - how they are created and communication between them.

Please provide some details to understand the basics. Appreciate if hyperlinks are given as I already a no. of links but able get the exact picutre on this.

[former_member204746 · Accepted solution]

when SAP starts, it uses OPS$ mechanism to connect to Oracle and retrieve password for Oracle user SAPR3, SAPSR3 or SAP[SID]. for proof of that, check dev_w0 or trans.log.

once this is done, the rest of communications are done that that user (SAPR3, SAPSR3 or SAP[SID]).

Oracle client uses tnsnames.ora at client level and listener.ora at server level.

Good luck.

[Former Member · Accepted solution]

Like to know some details on these OPS$ mechnism.

Found the following details in dev_w0 :-

kernel runs with dp version 232(ext=109) (@(#) DPLIB-INT-VERSION-232)

M length of sys_adm_ext is 364 bytes

M ***LOG Q01=> ThInit, WPStart (Workproc 0 122773782) [thxxhead.c 1281]

M ThInit: running on host sap<SID>

M calling db_connect ...

C Got LIBPATH=/usr/lib:/lib:/usr/sap/<SID>/SYS/exe/run:/oracle/client/10x_64/instantclient from environment

C Oracle Client Version: '10.2.0.2.0'

C Client NLS settings: AMERICAN_AMERICA.WE8DEC

C Logon as OPS$-user to get SAPSR3's password

C Connecting as /@<SID> on connection 0 (nls_hdl 0) ... (dbsl 700 250407)

C Nls CharacterSet NationalCharSet C EnvHp ErrHp ErrHpBatch

C 0 WE8DEC 1 112859e40 112865178 112864a28

C Attaching to DB Server <SID> (con_hdl=0,svchp=112862858,srvhp=1128674d8)

C Starting user session (con_hdl=0,svchp=112862858,srvhp=1128674d8,usrhp=112861c60)

C Now '/@<SID>' is connected (con_hdl 0, nls_hdl 0).

C Got SAPSR3's password from OPS$-user

C Disconnecting from connection 0 ...

C Closing user session (con_hdl=0,svchp=112862858,usrhp=112861c60)

C Now I'm disconnected from ORACLE

C Connecting as SAPSR3/<pwd>@<SID> on connection 0 (nls_hdl 0) ... (dbsl 700 250407)

C Nls CharacterSet NationalCharSet C EnvHp ErrHp ErrHpBatch

C 0 WE8DEC 1 112859e40 112865178 112864a28

C Starting user session (con_hdl=0,svchp=112862858,srvhp=1128674d8,usrhp=112861c60)

C Now 'SAPSR3/<pwd>@<SID>' is connected (con_hdl 0, nls_hdl 0).

C Database NLS settings: AMERICAN_AMERICA.WE8DEC

C DB instance <SID> is running on sap<SID> with ORACLE version 10.2.0.4.0 since JAN 28, 2010, 00:55:44

B Connection 0 opened (DBSL handle 0)

B Wp Hdl ConName ConId ConState TX PRM RCT TIM MAX OPT Date Time DBHost

B 000 000 R/3 000000000 ACTIVE NO YES NO 000 255 255 20100128 012909 sap<SID>

M db_connect o.k.

Basically how authentication between SAP and Oracle takes place. What are the a/c that comes with SAP inst and what relevant a/c for these communication comes by default with Oracle Db installation.

[former_member204746 · Accepted solution]

in your case,

SAPINST creates OPS$<SID>ADM

SAPINST created SAPSR3

that's all. SAPINST does not create any other users at Oracle level.

[stefan_koehler · Accepted solution]

Hello Mike,

if you want to know how the oracle db connect mechanisms works .. there is a tiny blog series about this written by Michael Braunstein.

[DB connect mechanisms in Oracle and SAP - Part I|http://www.sdn.sap.com/irj/scn/weblogs?blog=/pub/wlg/7676] [original link is broken] [original link is broken] [original link is broken];

[DB connect mechanisms in Oracle and SAP - Part II|http://www.sdn.sap.com/irj/scn/weblogs?blog=/pub/wlg/7699] [original link is broken] [original link is broken] [original link is broken];

[DB connect mechanisms in Oracle and SAP - Part III|http://www.sdn.sap.com/irj/scn/weblogs?blog=/pub/wlg/7739] [original link is broken] [original link is broken] [original link is broken];

Regards

Stefan

[former_member204746 · Accepted solution]

one more thing, a SAP note also answers this:

SAP note 562863 - FAQ: Logon mechanisms

[Former Member · Accepted solution]

Thanks Stefan and Eric. Excellent blog, notes.

Lots of stuff for me..let me go through it. ..:)

Thanks a ton guys.

[Former Member · Accepted solution]

Question answered.